1
|
Britt RD, Rauchfuss TB, Rao G. The H-cluster of [FeFe] Hydrogenases: Its Enzymatic Synthesis and Parallel Inorganic Semisynthesis. Acc Chem Res 2024; 57:1941-1950. [PMID: 38937148 PMCID: PMC11256358 DOI: 10.1021/acs.accounts.4c00231] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/22/2024] [Revised: 06/12/2024] [Accepted: 06/14/2024] [Indexed: 06/29/2024]
Abstract
ConspectusNature's prototypical hydrogen-forming catalysts─hydrogenases─have attracted much attention because they catalyze hydrogen evolution at near zero overpotential and ambient conditions. Beyond any possible applications in the energy sphere, the hydrogenases feature complicated active sites, which implies novel biosynthetic pathways. In terms of the variety of cofactors, the [FeFe]-hydrogenase is among the most complex.For more than a decade, we have worked on the biosynthesis of the active site of [FeFe] hydrogenases. This site, the H-cluster, is a six-iron ensemble consisting of a [4Fe-4S]H cluster linked to a [2Fe]H cluster that is coordinated to CO, cyanide, and a unique organic azadithiolate ligand. Many years ago, three enzymes, namely, HydG, HydE, and HydF, were shown to be required for the biosynthesis and the in vitro maturation of [FeFe] hydrogenases. The structures of the maturases were determined crystallographically, but still little progress was made on the biosynthetic pathway. As described in this Account, the elucidation of the biosynthetic pathway began in earnest with the identification of a molecular iron-cysteinate complex produced within HydG.In this Account, we present our most recent progress toward the molecular mechanism of [2Fe]H biosynthesis using a collaborative approach involving cell-free biosynthesis, isotope and element-sensitive spectroscopies, as well as inorganic synthesis of purported biosynthetic intermediates. Our study starts from the radical SAM enzyme HydG that lyses tyrosine into CO and cyanide and forms an Fe(CO)2(CN)-containing species. Crystallographic identification of a unique auxiliary 5Fe-4S cluster in HydG leads to a proposed catalytic cycle in which a free cysteine-chelated "dangler" Fe serves as the platform for the stepwise formation of a [4Fe-4S][Fe(CO)(CN)(cysteinate)] intermediate, which releases the [Fe(CO)2(CN)(cysteinate)] product, Complex B. Since Complex B is unstable, we applied synthetic organometallic chemistry to make an analogue, syn-B, and showed that it fully replaces HydG in the in vitro maturation of the H-cluster. Syn-B serves as the substrate for the next radical SAM enzyme HydE, where the low-spin Fe(II) center is activated by 5'-dAdo• to form an adenosylated Fe(I) intermediate. We propose that this Fe(I) species strips the carbon backbone and dimerizes in HydE to form a [Fe2(SH)2(CO)4(CN)2]2- product. This mechanistic scenario is supported by the use of a synthetic version of this dimer complex, syn-dimer, which allows for the formation of active hydrogenase with only the HydF maturase. Further application of this semisynthesis strategy shows that an [Fe2(SCH2NH2)2(CO)4(CN)2]2- complex can activate the apo hydrogenase, marking it as the last biosynthetic intermediate en route to the H-cluster. This combined enzymatic and semisynthetic approach greatly accelerates our understanding of H-cluster biosynthesis. We anticipate additional mechanistic details regarding H-cluster biosynthesis to be gleaned, and this methodology may be further applied in the study of other complex metallocofactors.
Collapse
Affiliation(s)
- R. David Britt
- Department
of Chemistry, University of California,
Davis, Davis, California 95616, United
States
| | - Thomas B. Rauchfuss
- Department
of Chemistry, University of Illinois at
Urbana−Champaign, Urbana, Illinois 61820, United States
| | - Guodong Rao
- Department
of Chemistry, University of California,
Davis, Davis, California 95616, United
States
| |
Collapse
|
2
|
Hou X, Feng J, Franklin JL, Russo R, Guo Z, Zhou J, Gao JM, Liu HW, Wang B. Mechanistic Insights from the Crystal Structure and Computational Analysis of the Radical SAM Deaminase DesII. ADVANCED SCIENCE (WEINHEIM, BADEN-WURTTEMBERG, GERMANY) 2024:e2403494. [PMID: 38943270 DOI: 10.1002/advs.202403494] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 04/03/2024] [Revised: 05/06/2024] [Indexed: 07/01/2024]
Abstract
Radical S-adenosyl-L-methionine (SAM) enzymes couple the reductive cleavage of SAM to radical-mediated transformations that have proven to be quite broad in scope. DesII is one such enzyme from the biosynthetic pathway of TDP-desosamine where it catalyzes a radical-mediated deamination. Previous studies have suggested that this reaction proceeds via direct elimination of ammonia from an α-hydroxyalkyl radical or its conjugate base (i.e., a ketyl radical) rather than 1,2-migration of the amino group to form a carbinolamine radical intermediate. However, without a crystal structure, the active site features responsible for this chemistry have remained largely unknown. The crystallographic studies described herein help to fill this gap by providing a structural description of the DesII active site. Computational analyses based on the solved crystal structure are consistent with direct elimination and indicate that an active site glutamate residue likely serves as a general base to promote deprotonation of the α-hydroxyalkyl radical intermediate and elimination of the ammonia group.
Collapse
Affiliation(s)
- Xueli Hou
- Shaanxi Key Laboratory of Natural Products & Chemical Biology, College of Chemistry & Pharmacy, Northwest A&F University, Yangling, Shaanxi, 712100, China
- Key Laboratory of Quantitative Synthetic Biology, Shenzhen Institute of Synthetic Biology, Shenzhen Institutes of Advanced Technology, Chinese Academy of Sciences, Shenzhen, 518055, China
| | - Jianqiang Feng
- State Key Laboratory of Physical Chemistry of Solid Surfaces and Fujian Provincial Key Laboratory of Theoretical and Computational Chemistry, College of Chemistry and Chemical Engineering and Innovation Laboratory for Sciences and Technologies of Energy Materials of Fujian Province (IKKEM), Xiamen University, Xiamen, 361005, China
| | - Joseph Livy Franklin
- Division of Chemical Biology & Medicinal Chemistry, College of Pharmacy, University of Texas at Austin, Austin, TX, 78712, USA
| | - Ryan Russo
- Division of Chemical Biology & Medicinal Chemistry, College of Pharmacy, University of Texas at Austin, Austin, TX, 78712, USA
| | - Zhiyong Guo
- State Key Laboratory of Biocatalysis and Enzyme Engineering, Hubei Key Laboratory of Industrial Biotechnology, School of Life Sciences, Hubei University, Wuhan, 430062, China
| | - Jiahai Zhou
- Key Laboratory of Quantitative Synthetic Biology, Shenzhen Institute of Synthetic Biology, Shenzhen Institutes of Advanced Technology, Chinese Academy of Sciences, Shenzhen, 518055, China
- School of Food Science and Pharmaceutical Engineering, Nanjing Normal University, Nanjing, 210023, China
| | - Jin-Ming Gao
- Shaanxi Key Laboratory of Natural Products & Chemical Biology, College of Chemistry & Pharmacy, Northwest A&F University, Yangling, Shaanxi, 712100, China
| | - Hung-Wen Liu
- Division of Chemical Biology & Medicinal Chemistry, College of Pharmacy, University of Texas at Austin, Austin, TX, 78712, USA
- Department of Chemistry, University of Texas at Austin, Austin, TX, 78712, USA
| | - Binju Wang
- State Key Laboratory of Physical Chemistry of Solid Surfaces and Fujian Provincial Key Laboratory of Theoretical and Computational Chemistry, College of Chemistry and Chemical Engineering and Innovation Laboratory for Sciences and Technologies of Energy Materials of Fujian Province (IKKEM), Xiamen University, Xiamen, 361005, China
| |
Collapse
|
3
|
Cronan JE. Lipoic acid attachment to proteins: stimulating new developments. Microbiol Mol Biol Rev 2024; 88:e0000524. [PMID: 38624243 DOI: 10.1128/mmbr.00005-24] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 04/17/2024] Open
Abstract
SUMMARYLipoic acid-modified proteins are essential for central metabolism and pathogenesis. In recent years, the Escherichia coli and Bacillus subtilis lipoyl assembly pathways have been modified and extended to archaea and diverse eukaryotes including humans. These extensions include a new pathway to insert the key sulfur atoms of lipoate, several new pathways of lipoate salvage, and a novel use of lipoic acid in sulfur-oxidizing bacteria. Other advances are the modification of E. coli LplA for studies of protein localization and protein-protein interactions in cell biology and in enzymatic removal of lipoate from lipoyl proteins. Finally, scenarios have been put forth for the evolution of lipoate assembly in archaea.
Collapse
Affiliation(s)
- John E Cronan
- Department of Microbiology, University of Illinois, Urbana, Illinois, USA
- Department of Biochemistry, University of Illinois, Urbana, Illinois, USA
| |
Collapse
|
4
|
Guo Q, Morinaka BI. Accessing and exploring the unusual chemistry by radical SAM-RiPP enzymes. Curr Opin Chem Biol 2024; 81:102483. [PMID: 38917731 DOI: 10.1016/j.cbpa.2024.102483] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/03/2024] [Revised: 06/02/2024] [Accepted: 06/02/2024] [Indexed: 06/27/2024]
Abstract
Radical SAM enzymes involved in the biosynthesis of ribosomally synthesized and post-translationally modified peptides catalyze unusual transformations that lead to unique peptide scaffolds and building blocks. Several natural products from these pathways show encouraging antimicrobial activities and represent next-generation therapeutics for infectious diseases. These systems are uniquely configured to benefit from genome-mining approaches because minimal substrate and cognate modifying enzyme expression can reveal unique, chemically complex transformations that outperform late-stage chemical reactions. This report highlights the main strategies used to reveal these enzymatic transformations, which have relied mainly on genome mining using enzyme-first approaches. We describe the general biosynthetic components for rSAM enzymes and highlight emerging approaches that may broaden the discovery and study of rSAM-RiPP enzymes. The large number of uncharacterized rSAM proteins, coupled with their unpredictable transformations, will continue to be an essential and exciting resource for enzyme discovery.
Collapse
Affiliation(s)
- Qianqian Guo
- Department of Pharmacy and Pharmaceutical Sciences, Faculty of Science, National University of Singapore, Singapore
| | - Brandon I Morinaka
- Department of Pharmacy and Pharmaceutical Sciences, Faculty of Science, National University of Singapore, Singapore.
| |
Collapse
|
5
|
Jain S, Ospina F, Hammer SC. A New Age of Biocatalysis Enabled by Generic Activation Modes. JACS AU 2024; 4:2068-2080. [PMID: 38938808 PMCID: PMC11200230 DOI: 10.1021/jacsau.4c00247] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 03/22/2024] [Revised: 04/17/2024] [Accepted: 04/19/2024] [Indexed: 06/29/2024]
Abstract
Biocatalysis is currently undergoing a profound transformation. The field moves from relying on nature's chemical logic to a discipline that exploits generic activation modes, allowing for novel biocatalytic reactions and, in many instances, entirely new chemistry. Generic activation modes enable a wide range of reaction types and played a pivotal role in advancing the fields of organo- and photocatalysis. This perspective aims to summarize the principal activation modes harnessed in enzymes to develop new biocatalysts. Although extensively researched in the past, the highlighted activation modes, when applied within enzyme active sites, facilitate chemical transformations that have largely eluded efficient and selective catalysis. This advance is attributed to multiple tunable interactions in the substrate binding pocket that precisely control competing reaction pathways and transition states. We will highlight cases of new synthetic methodologies achieved by engineered enzymes and will provide insights into potential future developments in this rapidly evolving field.
Collapse
Affiliation(s)
| | | | - Stephan C. Hammer
- Research Group for Organic Chemistry
and Biocatalysis, Faculty of Chemistry, Bielefeld University, Universitätsstraße 25, 33615 Bielefeld, Germany
| |
Collapse
|
6
|
Li Y, Yu T, Feng X, Zhao B, Chen H, Yang H, Chen X, Zhang XH, Anderson HR, Burns NZ, Zeng F, Tao L, Zeng Z. Biosynthesis of GMGT lipids by a radical SAM enzyme associated with anaerobic archaea and oxygen-deficient environments. Nat Commun 2024; 15:5256. [PMID: 38898040 PMCID: PMC11186832 DOI: 10.1038/s41467-024-49650-x] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/18/2024] [Accepted: 06/11/2024] [Indexed: 06/21/2024] Open
Abstract
Archaea possess characteristic membrane-spanning lipids that are thought to contribute to the adaptation to extreme environments. However, the biosynthesis of these lipids is poorly understood. Here, we identify a radical S-adenosyl-L-methionine (SAM) enzyme that synthesizes glycerol monoalkyl glycerol tetraethers (GMGTs). The enzyme, which we name GMGT synthase (Gms), catalyzes the formation of a C(sp3)-C(sp3) linkage between the two isoprenoid chains of glycerol dialkyl glycerol tetraethers (GDGTs). This conclusion is supported by heterologous expression of gene gms from a GMGT-producing species in a methanogen, as well as demonstration of in vitro activity using purified Gms enzyme. Additionally, we show that genes encoding putative Gms homologs are present in obligate anaerobic archaea and in metagenomes obtained from oxygen-deficient environments, and appear to be absent in metagenomes from oxic settings.
Collapse
Affiliation(s)
- Yanan Li
- Department of Ocean Science and Engineering, Southern University of Science and Technology, Shenzhen, China
- Department of Chemistry, Southern University of Science and Technology, Shenzhen, China
| | - Ting Yu
- Department of Systems Biology and Institute for Biological Electron Microscopy, Southern University of Science and Technology, Shenzhen, China
| | - Xi Feng
- Department of Ocean Science and Engineering, Southern University of Science and Technology, Shenzhen, China
| | - Bo Zhao
- Department of Ocean Science and Engineering, Southern University of Science and Technology, Shenzhen, China
| | - Huahui Chen
- Department of Ocean Science and Engineering, Southern University of Science and Technology, Shenzhen, China
| | - Huan Yang
- State Key Laboratory of Biogeology and Environmental Geology, China University of Geosciences, Wuhan, China
| | - Xing Chen
- Frontiers Science Center for Deep Ocean Multispheres and Earth System, College of Marine Life Sciences, Ocean University of China, Qingdao, China
| | - Xiao-Hua Zhang
- Frontiers Science Center for Deep Ocean Multispheres and Earth System, College of Marine Life Sciences, Ocean University of China, Qingdao, China
| | | | - Noah Z Burns
- Department of Chemistry, Stanford University, Stanford, USA
| | - Fuxing Zeng
- Department of Systems Biology and Institute for Biological Electron Microscopy, Southern University of Science and Technology, Shenzhen, China.
| | - Lizhi Tao
- Department of Chemistry, Southern University of Science and Technology, Shenzhen, China.
| | - Zhirui Zeng
- Department of Ocean Science and Engineering, Southern University of Science and Technology, Shenzhen, China.
| |
Collapse
|
7
|
Brischigliaro M, Sierra-Magro A, Ahn A, Barrientos A. Mitochondrial ribosome biogenesis and redox sensing. FEBS Open Bio 2024. [PMID: 38849194 DOI: 10.1002/2211-5463.13844] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/29/2024] [Revised: 05/06/2024] [Accepted: 05/29/2024] [Indexed: 06/09/2024] Open
Abstract
Mitoribosome biogenesis is a complex process involving RNA elements encoded in the mitochondrial genome and mitoribosomal proteins typically encoded in the nuclear genome. This process is orchestrated by extra-ribosomal proteins, nucleus-encoded assembly factors, which play roles across all assembly stages to coordinate ribosomal RNA processing and maturation with the sequential association of ribosomal proteins. Both biochemical studies and recent cryo-EM structures of mammalian mitoribosomes have provided insights into their assembly process. In this article, we will briefly outline the current understanding of mammalian mitoribosome biogenesis pathways and the factors involved. Special attention is devoted to the recent identification of iron-sulfur clusters as structural components of the mitoribosome and a small subunit assembly factor, the existence of redox-sensitive cysteines in mitoribosome proteins and assembly factors, and the role they may play as redox sensor units to regulate mitochondrial translation under stress.
Collapse
Affiliation(s)
| | - Ana Sierra-Magro
- Department of Neurology, University of Miami Miller School of Medicine, FL, USA
| | - Ahram Ahn
- Department of Biochemistry and Molecular Biology, University of Miami Miller School of Medicine, FL, USA
| | - Antoni Barrientos
- Department of Neurology, University of Miami Miller School of Medicine, FL, USA
- Department of Biochemistry and Molecular Biology, University of Miami Miller School of Medicine, FL, USA
- Bruce W. Carter Department of Veterans Affairs VA Medical Center, Miami, FL, USA
| |
Collapse
|
8
|
Cheek LE, Zhu W. Structural features and substrate engagement in peptide-modifying radical SAM enzymes. Arch Biochem Biophys 2024; 756:110012. [PMID: 38663796 DOI: 10.1016/j.abb.2024.110012] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/18/2024] [Revised: 04/16/2024] [Accepted: 04/17/2024] [Indexed: 05/04/2024]
Abstract
In recent years, the biological significance of ribosomally synthesized, post-translationally modified peptides (RiPPs) and the intriguing chemistry catalyzed by their tailoring enzymes has garnered significant attention. A subgroup of bacterial radical S-adenosylmethionine (rSAM) enzymes can activate C-H bonds in peptides, which leads to the production of a diverse range of RiPPs. The remarkable ability of these enzymes to facilitate various chemical processes, to generate and harbor high-energy radical species, and to accommodate large substrates with a high degree of flexibility is truly intriguing. The wide substrate scope and diversity of the chemistry performed by rSAM enzymes raise one question: how does the protein environment facilitate these distinct chemical conversions while sharing a similar structural fold? In this review, we discuss recent advances in the field of RiPP-rSAM enzymes, with a particular emphasis on domain architectures and substrate engagements identified by biophysical and structural characterizations. We provide readers with a comparative analysis of six examples of RiPP-rSAM enzymes with experimentally characterized structures. Linking the structural elements and the nature of rSAM-catalyzed RiPP production will provide insight into the functional engineering of enzyme activity to harness their catalytic power in broader applications.
Collapse
Affiliation(s)
- Lilly E Cheek
- Department of Chemistry and Biochemistry, Florida State University, Tallahassee, FL, 32306, USA
| | - Wen Zhu
- Department of Chemistry and Biochemistry, Florida State University, Tallahassee, FL, 32306, USA.
| |
Collapse
|
9
|
Kisgeropoulos EC, Artz JH, Blahut M, Peters JW, King PW, Mulder DW. Properties of the iron-sulfur cluster electron transfer relay in an [FeFe]-hydrogenase that is tuned for H 2 oxidation catalysis. J Biol Chem 2024; 300:107292. [PMID: 38636659 PMCID: PMC11126806 DOI: 10.1016/j.jbc.2024.107292] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/12/2024] [Revised: 04/09/2024] [Accepted: 04/11/2024] [Indexed: 04/20/2024] Open
Abstract
[FeFe]-hydrogenases catalyze the reversible oxidation of H2 from electrons and protons at an organometallic active site cofactor named the H-cluster. In addition to the H-cluster, most [FeFe]-hydrogenases possess accessory FeS cluster (F-cluster) relays that function in mediating electron transfer with catalysis. There is significant variation in the structural properties of F-cluster relays among the [FeFe]-hydrogenases; however, it is unknown how this variation relates to the electronic and thermodynamic properties, and thus the electron transfer properties, of enzymes. Clostridium pasteurianum [FeFe]-hydrogenase II (CpII) exhibits a large catalytic bias for H2 oxidation (compared to H2 production), making it a notable system for examining if F-cluster properties contribute to the overall function and efficiency of the enzyme. By applying a combination of multifrequency and potentiometric electron paramagnetic resonance, we resolved two electron paramagnetic resonance signals with distinct power- and temperature-dependent properties at g = 2.058 1.931 1.891 (F2.058) and g = 2.061 1.920 1.887 (F2.061), with assigned midpoint potentials of -140 ± 18 mV and -406 ± 12 mV versus normal hydrogen electrode, respectively. Spectral analysis revealed features consistent with spin-spin coupling between the two [4Fe-4S] F-clusters, and possible functional models are discussed that account for the contribution of coupling to the electron transfer landscape. The results signify the interplay of electronic coupling and free energy properties and parameters of the FeS clusters to the electron transfer mechanism through the relay and provide new insight as to how relays functionally complement the catalytic directionality of active sites to achieve highly efficient catalysis.
Collapse
Affiliation(s)
| | - Jacob H Artz
- Biosciences Center, National Renewable Energy Laboratory, Golden, Colorado, USA
| | - Matthew Blahut
- Biosciences Center, National Renewable Energy Laboratory, Golden, Colorado, USA
| | - John W Peters
- Department of Chemistry and Biochemistry, The University of Oklahoma, Norman, Oklahoma, USA
| | - Paul W King
- Biosciences Center, National Renewable Energy Laboratory, Golden, Colorado, USA; Renewable and Sustainable Energy Institute, National Renewable Energy Laboratory and University of Colorado Boulder, Boulder, Colorado, USA
| | - David W Mulder
- Biosciences Center, National Renewable Energy Laboratory, Golden, Colorado, USA.
| |
Collapse
|
10
|
Deng WH, Liao RZ. Cysteine Radical and Glutamate Collaboratively Enable C-H Bond Activation and C-N Bond Cleavage in a Glycyl Radical Enzyme HplG. J Chem Inf Model 2024; 64:4168-4179. [PMID: 38745447 DOI: 10.1021/acs.jcim.4c00122] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 05/16/2024]
Abstract
Hydroxyprolines are abundant in nature and widely utilized by many living organisms. Isomerization of trans-4-hydroxy-d-proline (t4D-HP) to generate 2-amino-4-ketopentanoate has been found to need a glycyl radical enzyme HplG, which catalyzes the cleavage of the C-N bond, while dehydration of trans-4-hydroxy-l-proline involves a homologous enzyme of HplG. Herein, molecular dynamics simulations and quantum mechanics/molecular mechanics (QM/MM) calculations are employed to understand the reaction mechanism of HplG. Two possible reaction pathways of HplG have been explored to decipher the origin of its chemoselectivity. The QM/MM calculations reveal that the isomerization proceeds via an initial hydrogen shift from the Cγ site of t4D-HP to a catalytic cysteine radical, followed by cleavage of the Cδ-N bond in t4D-HP to form a radical intermediate that captures a hydrogen atom from the cysteine. Activation of the Cδ-H bond in t4D-HP to bring about dehydration of t4D-HP possesses an extremely high energy barrier, thus rendering the dehydration pathway implausible in HplG. On the basis of the current calculations, conserved residue Glu429 plays a pivotal role in the isomerization pathway: the hydrogen bonding between it and t4D-HP weakens the hydroxyalkyl Cγ-Hγ bond, and it acts as a proton acceptor to trigger the cleavage of the C-N bond in t4D-HP. Our current QM/MM calculations rationalize the origin of the experimentally observed chemoselectivity of HplG and propose an H-bond-assisted bond activation strategy in radical-containing enzymes. These findings have general implications on radical-mediated enzymatic catalysis and expand our understanding of how nature wisely and selectively activates the C-H bond to modulate catalytic selectivity.
Collapse
Affiliation(s)
- Wen-Hao Deng
- Key Laboratory of Material Chemistry for Energy Conversion and Storage, Ministry of Education, Hubei Key Laboratory of Bioinorganic Chemistry and Materia Medica, Hubei Key Laboratory of Materials Chemistry and Service Failure, School of Chemistry and Chemical Engineering, Huazhong University of Science and Technology, Wuhan 430074, China
| | - Rong-Zhen Liao
- Key Laboratory of Material Chemistry for Energy Conversion and Storage, Ministry of Education, Hubei Key Laboratory of Bioinorganic Chemistry and Materia Medica, Hubei Key Laboratory of Materials Chemistry and Service Failure, School of Chemistry and Chemical Engineering, Huazhong University of Science and Technology, Wuhan 430074, China
| |
Collapse
|
11
|
Woodard AM, Peccati F, Navo CD, Jiménez-Osés G, Mitchell DA. Darobactin Substrate Engineering and Computation Show Radical Stability Governs Ether versus C-C Bond Formation. J Am Chem Soc 2024; 146:14328-14340. [PMID: 38728535 PMCID: PMC11225102 DOI: 10.1021/jacs.4c03994] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 05/12/2024]
Abstract
The Gram-negative selective antibiotic darobactin A has attracted interest owing to its intriguing fused bicyclic structure and unique targeting of the outer membrane protein BamA. Darobactin, a ribosomally synthesized and post-translationally modified peptide (RiPP), is produced by a radical S-adenosyl methionine (rSAM)-dependent enzyme (DarE) and contains one ether and one C-C cross-link. Herein, we analyze the substrate tolerance of DarE and describe an underlying catalytic principle of the enzyme. These efforts produced 51 enzymatically modified darobactin variants, revealing that DarE can install the ether and C-C cross-links independently and in different locations on the substrate. Notable variants with fused bicyclic structures were characterized, including darobactin W3Y, with a non-Trp residue at the twice-modified central position, and darobactin K5F, which displays a fused diether ring pattern. While lacking antibiotic activity, quantum mechanical modeling of darobactins W3Y and K5F aided in the elucidation of the requisite features for high-affinity BamA engagement. We also provide experimental evidence for β-oxo modification, which adds support for a proposed DarE mechanism. Based on these results, ether and C-C cross-link formation was investigated computationally, and it was determined that more stable and longer-lived aromatic Cβ radicals correlated with ether formation. Further, molecular docking and transition state structures based on high-level quantum mechanical calculations support the different indole connectivity observed for ether (Trp-C7) and C-C (Trp-C6) cross-links. Finally, mutational analysis and protein structural predictions identified substrate residues that govern engagement to DarE. Our work informs on darobactin scaffold engineering and further unveils the underlying principles of rSAM catalysis.
Collapse
Affiliation(s)
- Austin M Woodard
- Department of Chemistry, University of Illinois at Urbana─Champaign, Urbana, Illinois 61801, United States
- Carl R. Woese Institute for Genomic Biology, University of Illinois at Urbana─Champaign, Urbana, Illinois 61801, United States
| | - Francesca Peccati
- Center for Cooperative Research in Biosciences (CIC bioGUNE), Basque Research and Technology Alliance (BRTA), Bizkaia Technology Park, Building 801A, 48160 Derio, Spain
| | - Claudio D Navo
- Center for Cooperative Research in Biosciences (CIC bioGUNE), Basque Research and Technology Alliance (BRTA), Bizkaia Technology Park, Building 801A, 48160 Derio, Spain
| | - Gonzalo Jiménez-Osés
- Center for Cooperative Research in Biosciences (CIC bioGUNE), Basque Research and Technology Alliance (BRTA), Bizkaia Technology Park, Building 801A, 48160 Derio, Spain
- Ikerbasque, Basque Foundation for Science, 48013 Bilbao, Spain
| | - Douglas A Mitchell
- Department of Chemistry, University of Illinois at Urbana─Champaign, Urbana, Illinois 61801, United States
- Carl R. Woese Institute for Genomic Biology, University of Illinois at Urbana─Champaign, Urbana, Illinois 61801, United States
- Department of Microbiology, University of Illinois at Urbana─Champaign, Urbana, Illinois 61801, United States
| |
Collapse
|
12
|
Phan CS, Morinaka BI. Bacterial cyclophane-containing RiPPs from radical SAM enzymes. Nat Prod Rep 2024; 41:708-720. [PMID: 38047390 DOI: 10.1039/d3np00030c] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/05/2023]
Abstract
Covering: 2016 to 2023Ribosomally synthesized and posttranslationally modified peptides (RiPPs) continue to be a rich source of chemically diverse and bioactive peptide natural products. In recent years, cyclophane-containing RiPP natural products and their biosynthetic pathways have been more frequently encountered. This highlight will focus on bacterial monoaryl cyclophane-containing RiPPs. This class of RiPPs is produced by radical SAM/SPASM enzymes that form a crosslink between the aromatic ring and sidechain of two amino acid residues of the precursor peptide. Selected natural products from these pathways exhibit specific antibacterial activity against gram-negative pathogens. The approaches used to discover these pathways and products will be described and categorized as natural product-first or enzyme-first. The breadth of ring systems formed by the enzymes, enzyme mechanism, and recent reports of synthetic methods for constructing these ring systems will also be presented. Bacterial cyclophane-containing RiPPs and their biosynthetic enzymes represent an untapped source of scaffolds for drug discovery and tools for synthetic biology.
Collapse
Affiliation(s)
- Chin-Soon Phan
- Department of Pharmacy, National University of Singapore, 4 Science Dr 2, Singapore 117544, Singapore.
| | - Brandon I Morinaka
- Department of Pharmacy, National University of Singapore, 4 Science Dr 2, Singapore 117544, Singapore.
| |
Collapse
|
13
|
Sengupta S, Pabbaraja S, Mehta G. Natural products from the human microbiome: an emergent frontier in organic synthesis and drug discovery. Org Biomol Chem 2024; 22:4006-4030. [PMID: 38669195 DOI: 10.1039/d4ob00236a] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 04/28/2024]
Abstract
Often referred to as the "second genome", the human microbiome is at the epicenter of complex inter-habitat biochemical networks like the "gut-brain axis", which has emerged as a significant determinant of cognition, overall health and well-being, as well as resistance to antibiotics and susceptibility to diseases. As part of a broader understanding of the nexus between the human microbiome, diseases and microbial interactions, whether encoded secondary metabolites (natural products) play crucial signalling roles has been the subject of intense scrutiny in the recent past. A major focus of these activities involves harvesting the genomic potential of the human microbiome via bioinformatics guided genome mining and culturomics. Through these efforts, an impressive number of structurally intriguing antibiotics, with enhanced chemical diversity vis-à-vis conventional antibiotics have been isolated from human commensal bacteria, thereby generating considerable interest in their total synthesis and expanding their therapeutic space for drug discovery. These developments augur well for the discovery of new drugs and antibiotics, particularly in the context of challenges posed by mycobacterial resistance and emerging new diseases. The current landscape of various synthetic campaigns and drug discovery initiatives on antibacterial natural products from the human microbiome is captured in this review with an intent to stimulate further activities in this interdisciplinary arena among the new generation.
Collapse
Affiliation(s)
- Saumitra Sengupta
- School of Chemistry, University of Hyderabad, Hyderabad-500046, India.
- Department of Organic Synthesis and Process Chemistry, CSIR-Indian Institute of Chemical Technology, Hyderabad-500007, India
| | - Srihari Pabbaraja
- Department of Organic Synthesis and Process Chemistry, CSIR-Indian Institute of Chemical Technology, Hyderabad-500007, India
- Academy of Scientific & Innovative Research (AcSIR), Ghaziabad 201002, India
| | - Goverdhan Mehta
- School of Chemistry, University of Hyderabad, Hyderabad-500046, India.
| |
Collapse
|
14
|
Qu D, Ge P, Botella L, Park SW, Lee HN, Thornton N, Bean JM, Krieger IV, Sacchettini JC, Ehrt S, Aldrich CC, Schnappinger D. Mycobacterial biotin synthases require an auxiliary protein to convert dethiobiotin into biotin. Nat Commun 2024; 15:4161. [PMID: 38755122 PMCID: PMC11099021 DOI: 10.1038/s41467-024-48448-1] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/27/2023] [Accepted: 04/24/2024] [Indexed: 05/18/2024] Open
Abstract
Lipid biosynthesis in the pathogen Mycobacterium tuberculosis depends on biotin for posttranslational modification of key enzymes. However, the mycobacterial biotin synthetic pathway is not fully understood. Here, we show that rv1590, a gene of previously unknown function, is required by M. tuberculosis to synthesize biotin. Chemical-generic interaction experiments mapped the function of rv1590 to the conversion of dethiobiotin to biotin, which is catalyzed by biotin synthases (BioB). Biochemical studies confirmed that in contrast to BioB of Escherichia coli, BioB of M. tuberculosis requires Rv1590 (which we named "biotin synthase auxiliary protein" or BsaP), for activity. We found homologs of bsaP associated with bioB in many actinobacterial genomes, and confirmed that BioB of Mycobacterium smegmatis also requires BsaP. Structural comparisons of BsaP-associated biotin synthases with BsaP-independent biotin synthases suggest that the need for BsaP is determined by the [2Fe-2S] cluster that inserts sulfur into dethiobiotin. Our findings open new opportunities to seek BioB inhibitors to treat infections with M. tuberculosis and other pathogens.
Collapse
Affiliation(s)
- Di Qu
- Department of Microbiology and Immunology, Weill Cornell Medicine, New York, NY, USA
| | - Peng Ge
- Department of Medicinal Chemistry, University of Minnesota, Minneapolis, MN, USA
| | - Laure Botella
- Department of Microbiology and Immunology, Weill Cornell Medicine, New York, NY, USA
| | - Sae Woong Park
- Department of Microbiology and Immunology, Weill Cornell Medicine, New York, NY, USA
| | - Ha-Na Lee
- Department of Microbiology and Immunology, Weill Cornell Medicine, New York, NY, USA
| | - Natalie Thornton
- Department of Microbiology and Immunology, Weill Cornell Medicine, New York, NY, USA
| | - James M Bean
- Sloan Kettering Institute, Memorial Sloan Kettering Cancer Center, New York, NY, USA
| | - Inna V Krieger
- Department of Biochemistry and Biophysics, Texas A&M University, College Station, TX, USA
| | - James C Sacchettini
- Department of Biochemistry and Biophysics, Texas A&M University, College Station, TX, USA
| | - Sabine Ehrt
- Department of Microbiology and Immunology, Weill Cornell Medicine, New York, NY, USA
| | - Courtney C Aldrich
- Department of Medicinal Chemistry, University of Minnesota, Minneapolis, MN, USA.
| | - Dirk Schnappinger
- Department of Microbiology and Immunology, Weill Cornell Medicine, New York, NY, USA.
| |
Collapse
|
15
|
Fu H, Hyster TK. From Ground-State to Excited-State Activation Modes: Flavin-Dependent "Ene"-Reductases Catalyzed Non-natural Radical Reactions. Acc Chem Res 2024; 57:1446-1457. [PMID: 38603772 DOI: 10.1021/acs.accounts.4c00129] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 04/13/2024]
Abstract
Enzymes are desired catalysts for chemical synthesis, because they can be engineered to provide unparalleled levels of efficiency and selectivity. Yet, despite the astonishing array of reactions catalyzed by natural enzymes, many reactivity patterns found in small molecule catalysts have no counterpart in the living world. With a detailed understanding of the mechanisms utilized by small molecule catalysts, we can identify existing enzymes with the potential to catalyze reactions that are currently unknown in nature. Over the past eight years, our group has demonstrated that flavin-dependent "ene"-reductases (EREDs) can catalyze various radical-mediated reactions with unparalleled levels of selectivity, solving long-standing challenges in asymmetric synthesis.This Account presents our development of EREDs as general catalysts for asymmetric radical reactions. While we have developed multiple mechanisms for generating radicals within protein active sites, this account will focus on examples where flavin mononucleotide hydroquinone (FMNhq) serves as an electron transfer radical initiator. While our initial mechanistic hypotheses were rooted in electron-transfer-based radical initiation mechanisms commonly used by synthetic organic chemists, we ultimately uncovered emergent mechanisms of radical initiation that are unique to the protein active site. We will begin by covering intramolecular reactions and discussing how the protein activates the substrate for reduction by altering the redox-potential of alkyl halides and templating the charge transfer complex between the substrate and flavin-cofactor. Protein engineering has been used to modify the fundamental photophysics of these reactions, highlighting the opportunity to tune these systems further by using directed evolution. This section highlights the range of coupling partners and radical termination mechanisms available to intramolecular reactions.The next section will focus on intermolecular reactions and the role of enzyme-templated ternary charge transfer complexes among the cofactor, alkyl halide, and coupling partner in gating electron transfer to ensure that it only occurs when both substrates are bound within the protein active site. We will highlight the synthetic applications available to this activation mode, including olefin hydroalkylation, carbohydroxylation, arene functionalization, and nitronate alkylation. This section also discusses how the protein can favor mechanistic steps that are elusive in solution for the asymmetric reductive coupling of alkyl halides and nitroalkanes. We are aware of several recent EREDs-catalyzed photoenzymatic transformations from other groups. We will discuss results from these papers in the context of understanding the nuances of radical initiation with various substrates.These biocatalytic asymmetric radical reactions often complement the state-of-the-art small-molecule-catalyzed reactions, making EREDs a valuable addition to a chemist's synthetic toolbox. Moreover, the underlying principles studied with these systems are potentially operative with other cofactor-dependent proteins, opening the door to different types of enzyme-catalyzed radical reactions. We anticipate that this Account will serve as a guide and inspire broad interest in repurposing existing enzymes to access new transformations.
Collapse
Affiliation(s)
- Haigen Fu
- NHC Key Laboratory of Biotechnology for Microbial Drugs, Institute of Medicinal Biotechnology, Chinese Academy of Medical Sciences & Peking Union Medical College, Beijing 100050, China
| | - Todd K Hyster
- Department of Chemistry, Princeton University, Princeton, New Jersey 08544, United States
| |
Collapse
|
16
|
Phan CS, Chang L, Nguyen TQN, Suarez AFL, Ho XH, Chen H, Koh IYF, Morinaka BI. Substrate Promiscuity of the Triceptide Maturase XncB Leads to Incorporation of Various Amino Acids and Detection of Oxygenated Products. ACS Chem Biol 2024; 19:855-860. [PMID: 38452396 DOI: 10.1021/acschembio.3c00782] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 03/09/2024]
Abstract
Triceptides are cyclophane-containing ribosomally synthesized and post-translationally modified peptides. The characteristic cross-links are formed between an aromatic ring to Cβ on three-residue Ω1X2X3 motifs (Ω1 = aromatic). Here, we explored the promiscuity of the XYE family triceptide maturase, XncB from Xenorhabdus nematophila DSM 3370. Single amino acid variants were coexpressed with XncB in vivo in Escherichia coli, and we show that a variety of amino acids can be incorporated into the Phe-Gly-Asn cyclophane. Aromatic amino acids at the X3 position were accepted by the enzyme but yielded hydroxylated, rather than the typical cyclophane, products. These studies show that oxygen can be inserted but diverges in the final product formed relative to daropeptide maturases. Finally, truncations of the leader peptide showed that it is necessary for complete modification by XncB.
Collapse
Affiliation(s)
- Chin-Soon Phan
- Department of Pharmacy, National University of Singapore, Singapore 117544, Singapore
| | - Litao Chang
- Department of Pharmacy, National University of Singapore, Singapore 117544, Singapore
| | - Thi Quynh Ngoc Nguyen
- Department of Pharmacy, National University of Singapore, Singapore 117544, Singapore
| | | | - Xuen Huei Ho
- Department of Pharmacy, National University of Singapore, Singapore 117544, Singapore
| | - Huiyi Chen
- Department of Pharmacy, National University of Singapore, Singapore 117544, Singapore
| | - Ivan Yu Fan Koh
- Department of Pharmacy, National University of Singapore, Singapore 117544, Singapore
| | - Brandon I Morinaka
- Department of Pharmacy, National University of Singapore, Singapore 117544, Singapore
| |
Collapse
|
17
|
Ütkür K, Mayer K, Liu S, Brinkmann U, Schaffrath R. Functional Integrity of Radical SAM Enzyme Dph1•Dph2 Requires Non-Canonical Cofactor Motifs with Tandem Cysteines. Biomolecules 2024; 14:470. [PMID: 38672486 PMCID: PMC11048331 DOI: 10.3390/biom14040470] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/24/2024] [Revised: 04/05/2024] [Accepted: 04/09/2024] [Indexed: 04/28/2024] Open
Abstract
The Dph1•Dph2 heterodimer from yeast is a radical SAM (RS) enzyme that generates the 3-amino-3-carboxy-propyl (ACP) precursor for diphthamide, a clinically relevant modification on eukaryotic elongation factor 2 (eEF2). ACP formation requires SAM cleavage and atypical Cys-bound Fe-S clusters in each Dph1 and Dph2 subunit. Intriguingly, the first Cys residue in each motif is found next to another ill-defined cysteine that we show is conserved across eukaryotes. As judged from structural modeling, the orientation of these tandem cysteine motifs (TCMs) suggests a candidate Fe-S cluster ligand role. Hence, we generated, by site-directed DPH1 and DPH2 mutagenesis, Dph1•Dph2 variants with cysteines from each TCM replaced individually or in combination by serines. Assays diagnostic for diphthamide formation in vivo reveal that while single substitutions in the TCM of Dph2 cause mild defects, double mutations almost entirely inactivate the RS enzyme. Based on enhanced Dph1 and Dph2 subunit instability in response to cycloheximide chases, the variants with Cys substitutions in their cofactor motifs are particularly prone to protein degradation. In sum, we identify a fourth functionally cooperative Cys residue within the Fe-S motif of Dph2 and show that the Cys-based cofactor binding motifs in Dph1 and Dph2 are critical for the structural integrity of the dimeric RS enzyme in vivo.
Collapse
Affiliation(s)
- Koray Ütkür
- Institut für Biologie, Fachgebiet Mikrobiologie, Universität Kassel, 34132 Kassel, Germany;
| | - Klaus Mayer
- Roche Pharma Research and Early Development (pRED), Large Molecule Research, Roche Innovation Center Munich, 82377 Penzberg, Germany; (K.M.); (U.B.)
| | - Shihui Liu
- Division of Infectious Diseases, Department of Medicine, University of Pittsburgh, Pittsburgh, PA 15261, USA;
| | - Ulrich Brinkmann
- Roche Pharma Research and Early Development (pRED), Large Molecule Research, Roche Innovation Center Munich, 82377 Penzberg, Germany; (K.M.); (U.B.)
| | - Raffael Schaffrath
- Institut für Biologie, Fachgebiet Mikrobiologie, Universität Kassel, 34132 Kassel, Germany;
| |
Collapse
|
18
|
Nguyen DT, Mitchell DA, van der Donk WA. Genome Mining for New Enzyme Chemistry. ACS Catal 2024; 14:4536-4553. [PMID: 38601780 PMCID: PMC11002830 DOI: 10.1021/acscatal.3c06322] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/27/2023] [Revised: 02/09/2024] [Accepted: 02/13/2024] [Indexed: 04/12/2024]
Abstract
A revolution in the field of biocatalysis has enabled scalable access to compounds of high societal values using enzymes. The construction of biocatalytic routes relies on the reservoir of available enzymatic transformations. A review of uncharacterized proteins predicted from genomic sequencing projects shows that a treasure trove of enzyme chemistry awaits to be uncovered. This Review highlights enzymatic transformations discovered through various genome mining methods and showcases their potential future applications in biocatalysis.
Collapse
Affiliation(s)
- Dinh T. Nguyen
- Department
of Chemistry, Carl R. Woese Institute for Genomic Biology, University of Illinois at Urbana-Champaign, Urbana, Illinois 61801, United States
| | - Douglas A. Mitchell
- Department
of Chemistry, Carl R. Woese Institute for Genomic Biology, University of Illinois at Urbana-Champaign, Urbana, Illinois 61801, United States
| | - Wilfred A. van der Donk
- Department
of Chemistry, Carl R. Woese Institute for Genomic Biology, University of Illinois at Urbana-Champaign, Urbana, Illinois 61801, United States
- Howard
Hughes Medical Institute at the University of Illinois at Urbana-Champaign, Urbana, Illinois 61801, United States
| |
Collapse
|
19
|
Key M, Baptista CG, Bergmann A, Floyd K, Blader IJ, Dou Z. Toxoplasma gondii harbors a hypoxia-responsive coproporphyrinogen dehydrogenase-like protein. mSphere 2024; 9:e0009224. [PMID: 38411121 PMCID: PMC10964404 DOI: 10.1128/msphere.00092-24] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/05/2024] [Accepted: 02/06/2024] [Indexed: 02/28/2024] Open
Abstract
Toxoplasma gondii is an apicomplexan parasite that is the cause of toxoplasmosis, a potentially lethal disease for immunocompromised individuals. During in vivo infection, the parasites encounter various growth environments, such as hypoxia. Therefore, the metabolic enzymes in the parasites must adapt to such changes to fulfill their nutritional requirements. Toxoplasma can de novo biosynthesize some nutrients, such as heme. The parasites heavily rely on their own heme production for intracellular survival. Notably, the antepenultimate step within this pathway is facilitated by coproporphyrinogen III oxidase (CPOX), which employs oxygen to convert coproporphyrinogen III to protoporphyrinogen IX through oxidative decarboxylation. Conversely, some bacteria can accomplish this conversion independently of oxygen through coproporphyrinogen dehydrogenase (CPDH). Genome analysis found a CPDH ortholog in Toxoplasma. The mutant Toxoplasma lacking CPOX displays significantly reduced growth, implying that T. gondii CPDH (TgCPDH) potentially functions as an alternative enzyme to perform the same reaction as CPOX under low-oxygen conditions. In this study, we demonstrated that TgCPDH exhibits CPDH activity by complementing it in a heme synthesis-deficient Salmonella mutant. Additionally, we observed an increase in TgCPDH expression in Toxoplasma when it grew under hypoxic conditions. However, deleting TgCPDH in both wild-type and heme-deficient parasites did not alter their intracellular growth under both ambient and low-oxygen conditions. This research marks the first report of a CPDH-like protein in eukaryotic cells. Although TgCPDH responds to hypoxic conditions and possesses enzymatic activity, our findings revealed that it does not directly affect acute Toxoplasma infections in vitro and in vivo. IMPORTANCE Toxoplasma gondii is a ubiquitous parasite capable of infecting a wide range of warm-blooded hosts, including humans. During its life cycle, these parasites must adapt to varying environmental conditions, including situations with low-oxygen levels, such as intestine and spleen tissues. Our research, in conjunction with studies conducted by other laboratories, has revealed that Toxoplasma primarily relies on its own heme production during acute infections. Intriguingly, in addition to this classical heme biosynthetic pathway, the parasites encode a putative oxygen-independent coproporphyrinogen dehydrogenase (CPDH), suggesting its potential contribution to heme production under varying oxygen conditions, a feature typically observed in simpler organisms like bacteria. Notably, so far, CPDH has only been identified in some bacteria for heme biosynthesis. Our study discovered that Toxoplasma harbors a functional enzyme displaying CPDH activity, which alters its expression in the parasites when they face fluctuating oxygen levels in their surroundings.
Collapse
Affiliation(s)
- Melanie Key
- Department of Biological Sciences, Clemson University, Clemson, South Carolina, USA
- Eukaryotic Pathogens Innovation Center, Clemson University, Clemson, South Carolina, USA
| | - Carlos Gustavo Baptista
- Department of Microbiology and Immunology, University at Buffalo School of Medicine, The State University of New York, Buffalo, New York, USA
| | - Amy Bergmann
- Department of Biological Sciences, Clemson University, Clemson, South Carolina, USA
| | - Katherine Floyd
- Department of Biological Sciences, Clemson University, Clemson, South Carolina, USA
| | - Ira J. Blader
- Department of Microbiology and Immunology, University at Buffalo School of Medicine, The State University of New York, Buffalo, New York, USA
| | - Zhicheng Dou
- Department of Biological Sciences, Clemson University, Clemson, South Carolina, USA
- Eukaryotic Pathogens Innovation Center, Clemson University, Clemson, South Carolina, USA
| |
Collapse
|
20
|
Ma S, Chen H, Liu S, Huang X, Mo T, Liu WQ, Zhang W, Ding W, Zhang Q. A gene-encoded aldehyde tag repurposed from RiPP cyclophane-forming pathway. Bioorg Med Chem Lett 2024; 101:129653. [PMID: 38360420 DOI: 10.1016/j.bmcl.2024.129653] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/17/2023] [Revised: 01/19/2024] [Accepted: 02/08/2024] [Indexed: 02/17/2024]
Abstract
Gene-encoded aldehyde tag technology has been widely utilized in protein bioorthogonal chemistry and biotechnological application. Herein, we report utilization of the promiscuous rSAM cyclophane synthase SjiB involved in triceptide biosynthesis as a dedicated and highly efficient formylglycine synthase. The new aldehyde tag sequence in this system, YQSSI, is biosynthetically orthogonal to the known aldehyde tag (C/S)x(P/A)xR. The potential use of SjiB/YQSSI aldehyde tag system was further validated in fluorescent labelling of model proteins.
Collapse
Affiliation(s)
- Suze Ma
- Department of Chemistry, Fudan University, Shanghai 200433, China
| | - Heng Chen
- Department of Chemistry, Fudan University, Shanghai 200433, China; State Key Laboratory of Microbial Metabolism, School of Life Sciences & Biotechnology, Shanghai Jiao Tong University, Shanghai 200240, China
| | - Shuxun Liu
- Department of Chemistry, Fudan University, Shanghai 200433, China
| | - Xuedong Huang
- Department of Chemistry, Fudan University, Shanghai 200433, China
| | - Tianlu Mo
- School of Health Science and Engineering, University of Shanghai for Science and Technology, Shanghai 200093, China
| | - Wan-Qiu Liu
- School of Physical Science and Technology, ShanghaiTech University, Shanghai 201210, China
| | - Wei Zhang
- Key Laboratory of Extreme Environmental Microbial Resources and Engineering of Gansu Province, Northwest Institute of Eco-Environment and Resources, Chinese Academy of Sciences, Lanzhou, 730000, China
| | - Wei Ding
- State Key Laboratory of Microbial Metabolism, School of Life Sciences & Biotechnology, Shanghai Jiao Tong University, Shanghai 200240, China
| | - Qi Zhang
- Department of Chemistry, Fudan University, Shanghai 200433, China.
| |
Collapse
|
21
|
Ma B, Britt RD, Tao L. Radical SAM Enzyme PylB Generates a Lysyl Radical Intermediate in the Biosynthesis of Pyrrolysine by Using SAM as a Cofactor. J Am Chem Soc 2024; 146:6544-6556. [PMID: 38426740 DOI: 10.1021/jacs.3c11266] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 03/02/2024]
Abstract
Pyrrolysine, the 22nd amino acid encoded by the natural genetic code, is essential for methanogenic archaea to catabolize methylamines into methane. The structure of pyrrolysine consists of a methylated pyrroline carboxylate that is linked to the ε-amino group of the l-lysine via an amide bond. The biosynthesis of pyrrolysine requires three enzymes: PylB, PylC, and PylD. PylB is a radical S-adenosyl-l-methionine (SAM) enzyme and catalyzes the first biosynthetic step, the isomerization of l-lysine into methylornithine. PylC catalyzes an ATP-dependent ligation of methylornithine and a second l-lysine to form l-lysine-Nε-methylornithine. The last biosynthetic step is catalyzed by PylD via oxidation of the PylC product to form pyrrolysine. While enzymatic reactions of PylC and PylD have been well characterized by X-ray crystallography and in vitro studies, mechanistic understanding of PylB is still relatively limited. Here, we report the first in vitro activity of PylB to form methylornithine via the isomerization of l-lysine. We also identify a lysyl C4 radical intermediate that is trapped, with its electronic structure and geometric structure well characterized by EPR and ENDOR spectroscopy. In addition, we demonstrate that SAM functions as a catalytic cofactor in PylB catalysis rather than canonically as a cosubstrate. This work provides detailed mechanistic evidence for elucidating the carbon backbone rearrangement reaction catalyzed by PylB during the biosynthesis of pyrrolysine.
Collapse
Affiliation(s)
- Baixu Ma
- Department of Chemistry, Southern University of Science and Technology, Shenzhen 518055, China
| | - R David Britt
- Department of Chemistry, University of California, Davis, Davis, California 95616, United States
| | - Lizhi Tao
- Department of Chemistry, Southern University of Science and Technology, Shenzhen 518055, China
| |
Collapse
|
22
|
Soualmia F, Cherrier MV, Chauviré T, Mauger M, Tatham P, Guillot A, Guinchard X, Martin L, Amara P, Mouesca JM, Daghmoum M, Benjdia A, Gambarelli S, Berteau O, Nicolet Y. Radical S-Adenosyl-l-Methionine Enzyme PylB: A C-Centered Radical to Convert l-Lysine into (3 R)-3-Methyl-d-Ornithine. J Am Chem Soc 2024; 146:6493-6505. [PMID: 38426440 DOI: 10.1021/jacs.3c03747] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 03/02/2024]
Abstract
PylB is a radical S-adenosyl-l-methionine (SAM) enzyme predicted to convert l-lysine into (3R)-3-methyl-d-ornithine, a precursor in the biosynthesis of the 22nd proteogenic amino acid pyrrolysine. This protein highly resembles that of the radical SAM tyrosine and tryptophan lyases, which activate their substrate by abstracting a H atom from the amino-nitrogen position. Here, combining in vitro assays, analytical methods, electron paramagnetic resonance spectroscopy, and theoretical methods, we demonstrated that instead, PylB activates its substrate by abstracting a H atom from the Cγ position of l-lysine to afford the radical-based β-scission. Strikingly, we also showed that PylB catalyzes the reverse reaction, converting (3R)-3-methyl-d-ornithine into l-lysine and using catalytic amounts of the 5'-deoxyadenosyl radical. Finally, we identified significant in vitro production of 5'-thioadenosine, an unexpected shunt product that we propose to result from the quenching of the 5'-deoxyadenosyl radical species by the nearby [Fe4S4] cluster.
Collapse
Affiliation(s)
- Feryel Soualmia
- Université Paris-Saclay, Micalis Institute, ChemSyBio, Université Paris-Saclay, INRAE, AgroParisTech, 78350 Jouy-en-Josas, France
| | - Mickael V Cherrier
- Univ. Grenoble Alpes, CEA, CNRS, IBS, Metalloproteins Unit, F-38000 Grenoble, France
| | - Timothée Chauviré
- Univ. Grenoble Alpes, CEA, CNRS, IRIG-DIESE-SyMMES-CAMPE, F-38000 Grenoble, France
| | - Mickaël Mauger
- Université Paris-Saclay, Micalis Institute, ChemSyBio, Université Paris-Saclay, INRAE, AgroParisTech, 78350 Jouy-en-Josas, France
| | - Philip Tatham
- Université Paris-Saclay, Micalis Institute, ChemSyBio, Université Paris-Saclay, INRAE, AgroParisTech, 78350 Jouy-en-Josas, France
| | - Alain Guillot
- Université Paris-Saclay, Micalis Institute, ChemSyBio, Université Paris-Saclay, INRAE, AgroParisTech, 78350 Jouy-en-Josas, France
| | - Xavier Guinchard
- Université Paris-Saclay, CNRS, Institut de Chimie des Substances Naturelles, UPR 2301, 91198 Gif-sur-Yvette, France
| | - Lydie Martin
- Univ. Grenoble Alpes, CEA, CNRS, IBS, Metalloproteins Unit, F-38000 Grenoble, France
| | - Patricia Amara
- Univ. Grenoble Alpes, CEA, CNRS, IBS, Metalloproteins Unit, F-38000 Grenoble, France
| | - Jean-Marie Mouesca
- Univ. Grenoble Alpes, CEA, CNRS, IRIG-DIESE-SyMMES-CAMPE, F-38000 Grenoble, France
| | - Meriem Daghmoum
- Université Paris-Saclay, CNRS, Institut de Chimie des Substances Naturelles, UPR 2301, 91198 Gif-sur-Yvette, France
| | - Alhosna Benjdia
- Université Paris-Saclay, Micalis Institute, ChemSyBio, Université Paris-Saclay, INRAE, AgroParisTech, 78350 Jouy-en-Josas, France
| | - Serge Gambarelli
- Univ. Grenoble Alpes, CEA, CNRS, IRIG-DIESE-SyMMES-CAMPE, F-38000 Grenoble, France
| | - Olivier Berteau
- Université Paris-Saclay, Micalis Institute, ChemSyBio, Université Paris-Saclay, INRAE, AgroParisTech, 78350 Jouy-en-Josas, France
| | - Yvain Nicolet
- Univ. Grenoble Alpes, CEA, CNRS, IBS, Metalloproteins Unit, F-38000 Grenoble, France
| |
Collapse
|
23
|
Kubiak X, Polsinelli I, Chavas LMG, Fyfe CD, Guillot A, Fradale L, Brewee C, Grimaldi S, Gerbaud G, Thureau A, Legrand P, Berteau O, Benjdia A. Structural and mechanistic basis for RiPP epimerization by a radical SAM enzyme. Nat Chem Biol 2024; 20:382-391. [PMID: 38158457 DOI: 10.1038/s41589-023-01493-1] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/28/2022] [Accepted: 10/30/2023] [Indexed: 01/03/2024]
Abstract
D-Amino acid residues, found in countless peptides and natural products including ribosomally synthesized and post-translationally modified peptides (RiPPs), are critical for the bioactivity of several antibiotics and toxins. Recently, radical S-adenosyl-L-methionine (SAM) enzymes have emerged as the only biocatalysts capable of installing direct and irreversible epimerization in RiPPs. However, the mechanism underpinning this biochemical process is ill-understood and the structural basis for this post-translational modification remains unknown. Here we report an atomic-resolution crystal structure of a RiPP-modifying radical SAM enzyme in complex with its substrate properly positioned in the active site. Crystallographic snapshots, size-exclusion chromatography-small-angle x-ray scattering, electron paramagnetic resonance spectroscopy and biochemical analyses reveal how epimerizations are installed in RiPPs and support an unprecedented enzyme mechanism for peptide epimerization. Collectively, our study brings unique perspectives on how radical SAM enzymes interact with RiPPs and catalyze post-translational modifications in natural products.
Collapse
Affiliation(s)
- Xavier Kubiak
- Université Paris-Saclay, INRAE, AgroParisTech, Micalis Institute, ChemSyBio, Jouy-en-Josas, France
| | - Ivan Polsinelli
- Université Paris-Saclay, INRAE, AgroParisTech, Micalis Institute, ChemSyBio, Jouy-en-Josas, France
| | | | - Cameron D Fyfe
- Université Paris-Saclay, INRAE, AgroParisTech, Micalis Institute, ChemSyBio, Jouy-en-Josas, France
| | - Alain Guillot
- Université Paris-Saclay, INRAE, AgroParisTech, Micalis Institute, ChemSyBio, Jouy-en-Josas, France
| | - Laura Fradale
- Université Paris-Saclay, INRAE, AgroParisTech, Micalis Institute, ChemSyBio, Jouy-en-Josas, France
| | - Clémence Brewee
- Université Paris-Saclay, INRAE, AgroParisTech, Micalis Institute, ChemSyBio, Jouy-en-Josas, France
| | | | | | - Aurélien Thureau
- Synchrotron SOLEIL, HelioBio Group, L'Orme des Merisiers, Saint-Aubin, France
| | - Pierre Legrand
- Synchrotron SOLEIL, HelioBio Group, L'Orme des Merisiers, Saint-Aubin, France
| | - Olivier Berteau
- Université Paris-Saclay, INRAE, AgroParisTech, Micalis Institute, ChemSyBio, Jouy-en-Josas, France.
| | - Alhosna Benjdia
- Université Paris-Saclay, INRAE, AgroParisTech, Micalis Institute, ChemSyBio, Jouy-en-Josas, France.
| |
Collapse
|
24
|
Tian Y, Li XT, Liu JR, Cheng J, Gao A, Yang NY, Li Z, Guo KX, Zhang W, Wen HT, Li ZL, Gu QS, Hong X, Liu XY. A general copper-catalysed enantioconvergent C(sp 3)-S cross-coupling via biomimetic radical homolytic substitution. Nat Chem 2024; 16:466-475. [PMID: 38057367 DOI: 10.1038/s41557-023-01385-w] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/30/2023] [Accepted: 10/24/2023] [Indexed: 12/08/2023]
Abstract
Although α-chiral C(sp3)-S bonds are of enormous importance in organic synthesis and related areas, the transition-metal-catalysed enantioselective C(sp3)-S bond construction still represents an underdeveloped domain probably due to the difficult heterolytic metal-sulfur bond cleavage and notorious catalyst-poisoning capability of sulfur nucleophiles. Here we demonstrate the use of chiral tridentate anionic ligands in combination with Cu(I) catalysts to enable a biomimetic enantioconvergent radical C(sp3)-S cross-coupling reaction of both racemic secondary and tertiary alkyl halides with highly transformable sulfur nucleophiles. This protocol not only exhibits a broad substrate scope with high enantioselectivity but also provides universal access to a range of useful α-chiral alkyl organosulfur compounds with different sulfur oxidation states, thus providing a complementary approach to known asymmetric C(sp3)-S bond formation methods. Mechanistic results support a biomimetic radical homolytic substitution pathway for the critical C(sp3)-S bond formation step.
Collapse
Affiliation(s)
- Yu Tian
- Shenzhen Grubbs Institute and Department of Chemistry, Southern University of Science and Technology, Shenzhen, China
- Shenzhen Key Laboratory of Cross-Coupling Reactions, Southern University of Science and Technology, Shenzhen, China
| | - Xi-Tao Li
- Shenzhen Grubbs Institute and Department of Chemistry, Southern University of Science and Technology, Shenzhen, China
- School of Pharmaceutical Sciences (Shenzhen), Shenzhen Campus of Sun Yat-sen University, Shenzhen, Guangdong, P. R. China
| | - Ji-Ren Liu
- Shenzhen Grubbs Institute and Department of Chemistry, Southern University of Science and Technology, Shenzhen, China
- Center of Chemistry for Frontier Technologies, Department of Chemistry, State Key Laboratory of Clean Energy Utilization, Zhejiang University, Hangzhou, China
| | - Jian Cheng
- Shenzhen Grubbs Institute and Department of Chemistry, Southern University of Science and Technology, Shenzhen, China
| | - Ang Gao
- Academy for Advanced Interdisciplinary Studies and Department of Chemistry, Southern University of Science and Technology, Shenzhen, China
| | - Ning-Yuan Yang
- Shenzhen Grubbs Institute and Department of Chemistry, Southern University of Science and Technology, Shenzhen, China
| | - Zhuang Li
- Academy for Advanced Interdisciplinary Studies and Department of Chemistry, Southern University of Science and Technology, Shenzhen, China
| | - Kai-Xin Guo
- Academy for Advanced Interdisciplinary Studies and Department of Chemistry, Southern University of Science and Technology, Shenzhen, China
| | - Wei Zhang
- Shenzhen Grubbs Institute and Department of Chemistry, Southern University of Science and Technology, Shenzhen, China
| | - Han-Tao Wen
- Academy for Advanced Interdisciplinary Studies and Department of Chemistry, Southern University of Science and Technology, Shenzhen, China
| | - Zhong-Liang Li
- Academy for Advanced Interdisciplinary Studies and Department of Chemistry, Southern University of Science and Technology, Shenzhen, China
| | - Qiang-Shuai Gu
- Academy for Advanced Interdisciplinary Studies and Department of Chemistry, Southern University of Science and Technology, Shenzhen, China
| | - Xin Hong
- Center of Chemistry for Frontier Technologies, Department of Chemistry, State Key Laboratory of Clean Energy Utilization, Zhejiang University, Hangzhou, China
| | - Xin-Yuan Liu
- Shenzhen Grubbs Institute and Department of Chemistry, Southern University of Science and Technology, Shenzhen, China.
- Shenzhen Key Laboratory of Cross-Coupling Reactions, Southern University of Science and Technology, Shenzhen, China.
| |
Collapse
|
25
|
Walls WG, Vagstad AL, Delridge T, Piel J, Broderick WE, Broderick JB. Direct Detection of the α-Carbon Radical Intermediate Formed by OspD: Mechanistic Insights into Radical S-Adenosyl-l-methionine Peptide Epimerization. J Am Chem Soc 2024; 146:5550-5559. [PMID: 38364824 DOI: 10.1021/jacs.3c13829] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/18/2024]
Abstract
OspD is a radical S-adenosyl-l-methionine (SAM) peptide epimerase that converts an isoleucine (Ile) and valine (Val) of the OspA substrate to d-amino acids during biosynthesis of the ribosomally synthesized and post-translationally modified peptide (RiPP) natural product landornamide A. OspD is proposed to carry out this reaction via α-carbon (Cα) H-atom abstraction to form a peptidyl Cα radical that is stereospecifically quenched by hydrogen atom transfer (HAT) from a conserved cysteine (Cys). Here we use site-directed mutagenesis, freeze-quench trapping, isotopic labeling, and electron paramagnetic resonance (EPR) spectroscopy to provide new insights into the OspD catalytic mechanism including the direct observation of the substrate peptide Cα radical intermediate. The putative quenching Cys334 was changed to serine to generate an OspD C334S variant impaired in HAT quenching. The reaction of reduced OspD C334S with SAM and OspA freeze-quenched at 15 s exhibits a doublet EPR signal characteristic of a Cα radical coupled to a single β-H. Using isotopologues of OspA deuterated at either Ile or Val, or both Ile and Val, reveals that the initial Cα radical intermediate forms exclusively on the Ile of OspA. Time-dependent freeze quench coupled with EPR spectroscopy provided evidence for loss of the Ile Cα radical concomitant with gain of a Val Cα radical, directly demonstrating the N-to-C directionality of epimerization by OspD. These results provide direct evidence for the aforementioned OspD-catalyzed peptide epimerization mechanism via a central Cα radical intermediate during RiPP maturation of OspA, a mechanism that may extend to other proteusin peptide epimerases.
Collapse
Affiliation(s)
- William G Walls
- Department of Chemistry & Biochemistry, Montana State University, Bozeman, Montana 59717, United States
| | - Anna L Vagstad
- Institute of Microbiology, Eidgenössische Technische Hochschule (ETH) Zürich, Vladimir-Prelog-Weg 4, Zürich 8093, Switzerland
| | - Tyler Delridge
- Department of Chemistry & Biochemistry, Montana State University, Bozeman, Montana 59717, United States
| | - Jörn Piel
- Institute of Microbiology, Eidgenössische Technische Hochschule (ETH) Zürich, Vladimir-Prelog-Weg 4, Zürich 8093, Switzerland
| | - William E Broderick
- Department of Chemistry & Biochemistry, Montana State University, Bozeman, Montana 59717, United States
| | - Joan B Broderick
- Department of Chemistry & Biochemistry, Montana State University, Bozeman, Montana 59717, United States
| |
Collapse
|
26
|
Petchey MR, Ye Y, Spelling V, Finnigan JD, Gittings S, Johansson MJ, Hayes MA, Hyster TK. Regiodivergent Radical Termination for Intermolecular Biocatalytic C-C Bond Formation. J Am Chem Soc 2024; 146:5005-5010. [PMID: 38329236 PMCID: PMC10885151 DOI: 10.1021/jacs.4c00482] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/11/2024] [Revised: 01/24/2024] [Accepted: 01/24/2024] [Indexed: 02/09/2024]
Abstract
Radical hydrofunctionalizations of electronically unbiased dienes are challenging to render regioselective, because the products are nearly identical in energy. Here, we report two engineered FMN-dependent "ene"-reductases (EREDs) that catalyze regiodivergent hydroalkylations of cyclic and linear dienes. While previous studies focused exclusively on the stereoselectivity of alkene hydroalkylation, this work highlights that EREDs can control the regioselectivity of hydrogen atom transfer, providing a method for selectively preparing constitutional isomers that would be challenging to prepare using traditional synthetic methods. Engineering the ERED from Gluconabacter sp. (GluER) furnished a variant that favors the γ,δ-unsaturated ketone, while an engineered variant from a commercial ERED panel favors the δ,ε-unsaturated ketone. The effect of beneficial mutations has been investigated using substrate docking studies and the mechanism probed by isotope labeling experiments. A variety of α-bromo ketones can be coupled with cyclic and linear dienes. These interesting building blocks can also be further modified to generate difficult-to-access heterocyclic compounds.
Collapse
Affiliation(s)
- Mark R. Petchey
- Compound
Synthesis and Management, Discovery Sciences,
BioPharma R&D, AstraZeneca,
Pepparedsleden 1, 431 83 Mölndal, Sweden
| | - Yuxuan Ye
- Department
of Chemistry and Chemical Biology, Cornell
University, Ithaca 14850, New York, United States
| | - Victor Spelling
- Early
Chemical Development, Pharmaceutical Sciences, BioPharma R&D, AstraZeneca,
Pepparedsleden 1, 431 83 Mölndal, Sweden
| | - James D. Finnigan
- Prozomix
Ltd., Building 4, West
End Industrial Estate, Haltwhistle NE49 9HA, U.K.
| | - Samantha Gittings
- Prozomix
Ltd., Building 4, West
End Industrial Estate, Haltwhistle NE49 9HA, U.K.
| | - Magnus J. Johansson
- Medicinal
Chemistry, Research and Early Development, Cardiovascular, Renal and
Metabolism (CVRM), BioPharma R&D, AstraZeneca, Pepparedsleden 1, 431 83 Mölndal, Sweden
| | - Martin A. Hayes
- Compound
Synthesis and Management, Discovery Sciences,
BioPharma R&D, AstraZeneca,
Pepparedsleden 1, 431 83 Mölndal, Sweden
| | - Todd K. Hyster
- Department
of Chemistry and Chemical Biology, Cornell
University, Ithaca 14850, New York, United States
| |
Collapse
|
27
|
Ghebreamlak S, Stoian SA, Lees NS, Cronin B, Smith F, Ross MO, Telser J, Hoffman BM, Duin EC. The Active-Site [4Fe-4S] Cluster in the Isoprenoid Biosynthesis Enzyme IspH Adopts Unexpected Redox States during Ligand Binding and Catalysis. J Am Chem Soc 2024; 146:3926-3942. [PMID: 38291562 DOI: 10.1021/jacs.3c11674] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/01/2024]
Abstract
(E)-4-Hydroxy-3-methylbut-2-enyl diphosphate reductase, or IspH (formerly known as LytB), catalyzes the terminal step of the bacterial methylerythritol phosphate (MEP) pathway for isoprene synthesis. This step converts (E)-4-hydroxy-3-methylbut-2-enyl diphosphate (HMBPP) into one of two possible isomeric products, either isopentenyl diphosphate (IPP) or dimethylallyl diphosphate (DMAPP). This reaction involves the removal of the C4 hydroxyl group of HMBPP and addition of two electrons. IspH contains a [4Fe-4S] cluster in its active site, and multiple cluster-based paramagnetic species of uncertain redox and ligation states can be detected after incubation with reductant, addition of a ligand, or during catalysis. To characterize the clusters in these species, 57Fe-labeled samples of IspH were prepared and studied by electron paramagnetic resonance (EPR), 57Fe electron-nuclear double resonance (ENDOR), and Mössbauer spectroscopies. Notably, this ENDOR study provides a rarely reported, complete determination of the 57Fe hyperfine tensors for all four Fe ions in a [4Fe-4S] cluster. The resting state of the enzyme (Ox) has a diamagnetic [4Fe-4S]2+ cluster. Reduction generates [4Fe-4S]+ (Red) with both S = 1/2 and S = 3/2 spin ground states. When the reduced enzyme is incubated with substrate, a transient paramagnetic reaction intermediate is detected (Int) which is thought to contain a cluster-bound substrate-derived species. The EPR properties of Int are indicative of a 3+ iron-sulfur cluster oxidation state, and the Mössbauer spectra presented here confirm this. Incubation of reduced enzyme with the product IPP induced yet another paramagnetic [4Fe-4S]+ species (Red+P) with S = 1/2. However, the g-tensor of this state is commonly associated with a 3+ oxidation state, while Mössbauer parameters show features typical for 2+ clusters. Implications of these complicated results are discussed.
Collapse
Affiliation(s)
- Selamawit Ghebreamlak
- Department of Chemistry and Biochemistry, Auburn University, 179 Chemistry Building, Auburn, Alabama 36849, United States
| | - Sebastian A Stoian
- Department of Chemistry, University of Idaho, 875 Perimeter Drive, MS 2343 Moscow, Idaho 83844, United States
| | - Nicholas S Lees
- Department of Chemistry, Northwestern University, 2145 Sheridan Road, Evanston, Illinois 60208, United States
| | - Bryan Cronin
- Department of Chemistry and Biochemistry, Auburn University, 179 Chemistry Building, Auburn, Alabama 36849, United States
| | - Forrest Smith
- Department of Drug Discovery & Development, Auburn University, 4306 Walker Building, Auburn, Alabama 36849, United States
| | - Matthew O Ross
- Department of Chemistry, Northwestern University, 2145 Sheridan Road, Evanston, Illinois 60208, United States
| | - Joshua Telser
- Department of Biological, Chemical and Physical Sciences, Roosevelt University, 430 S. Michigan Avenue, Chicago, Illinois 60605, United States
| | - Brian M Hoffman
- Department of Chemistry, Northwestern University, 2145 Sheridan Road, Evanston, Illinois 60208, United States
| | - Evert C Duin
- Department of Chemistry and Biochemistry, Auburn University, 179 Chemistry Building, Auburn, Alabama 36849, United States
| |
Collapse
|
28
|
Johnson BA, Clark KA, Bushin LB, Spolar CN, Seyedsayamdost MR. Expanding the Landscape of Noncanonical Amino Acids in RiPP Biosynthesis. J Am Chem Soc 2024; 146:3805-3815. [PMID: 38316431 DOI: 10.1021/jacs.3c10824] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/07/2024]
Abstract
Advancements in DNA sequencing technologies and bioinformatics have enabled the discovery of new metabolic reactions from overlooked microbial species and metagenomic sequences. Using a bioinformatic co-occurrence strategy, we previously generated a network of ∼600 uncharacterized quorum-sensing-regulated biosynthetic gene clusters that code for ribosomally synthesized and post-translationally modified peptide (RiPP) natural products and are tailored by radical S-adenosylmethionine (RaS) enzymes in streptococci. The most complex of these is the GRC subfamily, named after a conserved motif in the precursor peptide and found exclusively in Streptococcus pneumoniae, the causative agent of bacterial pneumonia. In this study, using both in vivo and in vitro approaches, we have elucidated the modifications installed by the grc biosynthetic enzymes, including a ThiF-like adenylyltransferase/cyclase that generates a C-terminal Glu-to-Cys thiolactone macrocycle, and two RaS enzymes, which selectively epimerize the β-carbon of threonine and desaturate histidine to generate the first instances of l-allo-Thr and didehydrohistidine in RiPP biosynthesis. RaS-RiPPs that have been discovered thus far have stood out for their exotic macrocycles. The product of the grc cluster breaks this trend by generating two noncanonical residues rather than an unusual macrocycle in the peptide substrate. These modifications expand the landscape of nonproteinogenic amino acids in RiPP natural product biosynthesis and motivate downstream biocatalytic applications of the corresponding enzymes.
Collapse
Affiliation(s)
- Brooke A Johnson
- Department of Chemistry, Princeton University, Princeton, New Jersey 08544, United States
| | - Kenzie A Clark
- Department of Chemistry, Princeton University, Princeton, New Jersey 08544, United States
| | - Leah B Bushin
- Department of Chemistry, Princeton University, Princeton, New Jersey 08544, United States
| | - Calvin N Spolar
- Department of Chemistry, Princeton University, Princeton, New Jersey 08544, United States
| | - Mohammad R Seyedsayamdost
- Department of Chemistry, Princeton University, Princeton, New Jersey 08544, United States
- Department of Molecular Biology, Princeton University, Princeton, New Jersey 08544, United States
| |
Collapse
|
29
|
Yang H, Ho MB, Lundahl MN, Mosquera MA, Broderick WE, Broderick JB, Hoffman BM. ENDOR Spectroscopy Reveals the "Free" 5'-Deoxyadenosyl Radical in a Radical SAM Enzyme Active Site Actually is Chaperoned by Close Interaction with the Methionine-Bound [4Fe-4S] 2+ Cluster. J Am Chem Soc 2024; 146:3710-3720. [PMID: 38308759 DOI: 10.1021/jacs.3c09428] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/05/2024]
Abstract
1/2H and 13C hyperfine coupling constants to 5'-deoxyadenosyl (5'-dAdo•) radical trapped within the active site of the radical S-adenosyl-l-methionine (SAM) enzyme, pyruvate formate lyase-activating enzyme (PFL-AE), both in the absence of substrate and the presence of a reactive peptide-model of the PFL substrate, are completely characteristic of a classical organic free radical whose unpaired electron is localized in the 2pπ orbital of the sp2 C5'-carbon (J. Am. Chem. Soc. 2019, 141, 12139-12146). However, prior electron-nuclear double resonance (ENDOR) measurements had indicated that this 5'-dAdo• free radical is never truly "free": tight van der Waals contact with its target partners and active-site residues guide it in carrying out the exquisitely precise, regioselective reactions that are hallmarks of RS enzymes. Here, our understanding of how the active site chaperones 5'-dAdo• is extended through the finding that this apparently unexceptional organic free radical has an anomalous g-tensor and exhibits significant 57Fe, 13C, 15N, and 2H hyperfine couplings to the adjacent, isotopically labeled, methionine-bound [4Fe-4S]2+ cluster cogenerated with 5'-dAdo• during homolytic cleavage of cluster-bound SAM. The origin of the 57Fe couplings through nonbonded radical-cluster contact is illuminated by a formal exchange-coupling model and broken symmetry-density functional theory computations. Incorporation of ENDOR-derived distances from C5'(dAdo•) to labeled-methionine as structural constraints yields a model for active-site positioning of 5'-dAdo• with a short, nonbonded C5'-Fe distance (∼3 Å). This distance involves substantial motion of 5'-dAdo• toward the unique Fe of the [4Fe-4S]2+ cluster upon S-C(5') bond-cleavage, plausibly an initial step toward formation of the Fe-C5' bond of the organometallic complex, Ω, the central intermediate in catalysis by radical-SAM enzymes.
Collapse
Affiliation(s)
- Hao Yang
- Department of Chemistry, Northwestern University, Evanston, Illinois 60208, United States
| | - Madeline B Ho
- Department of Chemistry, Northwestern University, Evanston, Illinois 60208, United States
| | - Maike N Lundahl
- Department of Chemistry and Biochemistry, Montana State University, Bozeman, Montana 59717, United States
| | - Martín A Mosquera
- Department of Chemistry and Biochemistry, Montana State University, Bozeman, Montana 59717, United States
| | - William E Broderick
- Department of Chemistry and Biochemistry, Montana State University, Bozeman, Montana 59717, United States
| | - Joan B Broderick
- Department of Chemistry and Biochemistry, Montana State University, Bozeman, Montana 59717, United States
| | - Brian M Hoffman
- Department of Chemistry, Northwestern University, Evanston, Illinois 60208, United States
| |
Collapse
|
30
|
Lachowicz JC, Lennox-Hvenekilde D, Myling-Petersen N, Salomonsen B, Verkleij G, Acevedo-Rocha CG, Caddell B, Gronenberg LS, Almo SC, Sommer MOA, Genee HJ, Grove TL. Discovery of a Biotin Synthase That Utilizes an Auxiliary 4Fe-5S Cluster for Sulfur Insertion. J Am Chem Soc 2024; 146:1860-1873. [PMID: 38215281 PMCID: PMC10813225 DOI: 10.1021/jacs.3c05481] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/03/2023] [Revised: 12/12/2023] [Accepted: 12/13/2023] [Indexed: 01/14/2024]
Abstract
Biotin synthase (BioB) is a member of the Radical SAM superfamily of enzymes that catalyzes the terminal step of biotin (vitamin B7) biosynthesis, in which it inserts a sulfur atom in desthiobiotin to form a thiolane ring. How BioB accomplishes this difficult reaction has been the subject of much controversy, mainly around the source of the sulfur atom. However, it is now widely accepted that the sulfur atom inserted to form biotin stems from the sacrifice of the auxiliary 2Fe-2S cluster of BioB. Here, we bioinformatically explore the diversity of BioBs available in sequence databases and find an unexpected variation in the coordination of the auxiliary iron-sulfur cluster. After in vitro characterization, including the determination of biotin formation and representative crystal structures, we report a new type of BioB utilized by virtually all obligate anaerobic organisms. Instead of a 2Fe-2S cluster, this novel type of BioB utilizes an auxiliary 4Fe-5S cluster. Interestingly, this auxiliary 4Fe-5S cluster contains a ligated sulfide that we propose is used for biotin formation. We have termed this novel type of BioB, Type II BioB, with the E. coli 2Fe-2S cluster sacrificial BioB representing Type I. This surprisingly ubiquitous Type II BioB has implications for our understanding of the function and evolution of Fe-S clusters in enzyme catalysis, highlighting the difference in strategies between the anaerobic and aerobic world.
Collapse
Affiliation(s)
- Jake C. Lachowicz
- Department
of Biochemistry, Albert Einstein College
of Medicine, Bronx, New York 10461, United States
| | - David Lennox-Hvenekilde
- The
Novo Nordisk Foundation Center for Biosustainability, Technical University of Denmark, Kgs. Lyngby, 2800, Denmark
- Biosyntia
ApS, Copenhagen, 2100, Denmark
| | | | | | | | - Carlos G. Acevedo-Rocha
- The
Novo Nordisk Foundation Center for Biosustainability, Technical University of Denmark, Kgs. Lyngby, 2800, Denmark
- Biosyntia
ApS, Copenhagen, 2100, Denmark
| | | | | | - Steven C. Almo
- Department
of Biochemistry, Albert Einstein College
of Medicine, Bronx, New York 10461, United States
| | - Morten O. A. Sommer
- The
Novo Nordisk Foundation Center for Biosustainability, Technical University of Denmark, Kgs. Lyngby, 2800, Denmark
| | | | - Tyler L. Grove
- Department
of Biochemistry, Albert Einstein College
of Medicine, Bronx, New York 10461, United States
| |
Collapse
|
31
|
Zhang C, Seyedsayamdost MR. Widespread Peptide Surfactants with Post-translational C-methylations Promote Bacterial Development. BIORXIV : THE PREPRINT SERVER FOR BIOLOGY 2024:2024.01.23.576971. [PMID: 38328144 PMCID: PMC10849626 DOI: 10.1101/2024.01.23.576971] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 02/09/2024]
Abstract
Bacteria produce a variety of peptides to mediate nutrient acquisition, microbial interactions, and other physiological processes. Of special interest are surface-active peptides that aid in growth and development. Herein, we report the structure and characterization of clavusporins, unusual and hydrophobic ribosomal peptides with multiple C-methylations at unactivated carbon centers, which help drastically reduce the surface tension of water and thereby aid in Streptomyces development. The peptides are synthesized by a previously uncharacterized protein superfamily, termed DUF5825, in conjunction with a vitamin B12-dependent radical S-adenosylmethionine metalloenzyme. The operon encoding clavusporin is wide-spread among actinomycete bacteria, suggesting a prevalent role for clavusporins as morphogens in erecting aerial hyphae and thereby advancing sporulation and proliferation.
Collapse
Affiliation(s)
- Chen Zhang
- Department of Chemistry, Princeton University, Princeton, NJ 08544, United States
| | - Mohammad R. Seyedsayamdost
- Department of Chemistry, Princeton University, Princeton, NJ 08544, United States
- Department of Molecular Biology, Princeton University, Princeton, NJ 08544, United States
| |
Collapse
|
32
|
Jena S, Frenzen L, Chugh V, Wu J, Weyhermüller T, Auer AA, Werlé C. A Cooperative Cobalt-Driven System for One-Carbon Extension in the Synthesis of ( Z)-Silyl Enol Ethers from Aldehydes: Unlocking Regio- and Stereoselectivity. J Am Chem Soc 2023; 145:27922-27932. [PMID: 38086018 PMCID: PMC10755702 DOI: 10.1021/jacs.3c10491] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/22/2023] [Revised: 11/30/2023] [Accepted: 12/01/2023] [Indexed: 12/28/2023]
Abstract
The research presented herein explores a cobalt-based catalytic system, distinctively featuring a cooperative boron-centric element within its intricate ligand architecture. This system is strategically engineered to enable the integration of a singular carbon atom into aldehydes, a process culminating in the production of (Z)-silyl enol ethers. Beyond offering an efficient one-pot synthesis route, this method adeptly overcomes challenges inherent to conventional techniques, such as the need for large amounts of additives, restrictive functional group tolerance, and extreme reaction temperatures. Initial mechanistic studies suggest the potential role of a cobalt-carbene complex as a catalytically significant species and underscore the importance of the borane segment. Collectively, these observations highlight the potential of this system in advancing complex bond activation pursuits.
Collapse
Affiliation(s)
- Soumyashree Jena
- Max
Planck Institute for Chemical Energy Conversion, Stiftstr. 34−36, 45470 Mülheim an der Ruhr, Germany
- Ruhr
University Bochum, Universitätsstr.
150, 44801 Bochum, Germany
| | - Lars Frenzen
- Max
Planck Institute for Chemical Energy Conversion, Stiftstr. 34−36, 45470 Mülheim an der Ruhr, Germany
| | - Vishal Chugh
- Max
Planck Institute for Chemical Energy Conversion, Stiftstr. 34−36, 45470 Mülheim an der Ruhr, Germany
- Ruhr
University Bochum, Universitätsstr.
150, 44801 Bochum, Germany
| | - Jiajun Wu
- Max
Planck Institute for Chemical Energy Conversion, Stiftstr. 34−36, 45470 Mülheim an der Ruhr, Germany
| | - Thomas Weyhermüller
- Max
Planck Institute for Chemical Energy Conversion, Stiftstr. 34−36, 45470 Mülheim an der Ruhr, Germany
| | - Alexander A. Auer
- Max-Planck-Institut
für Kohlenforschung, Kaiser-Wilhelm-Platz 1, 45470 Mülheim an der Ruhr, Germany
| | - Christophe Werlé
- Max
Planck Institute for Chemical Energy Conversion, Stiftstr. 34−36, 45470 Mülheim an der Ruhr, Germany
- Ruhr
University Bochum, Universitätsstr.
150, 44801 Bochum, Germany
| |
Collapse
|
33
|
Eastman KS, Mifflin MC, Oblad PF, Roberts AG, Bandarian V. A Promiscuous rSAM Enzyme Enables Diverse Peptide Cross-linking. ACS BIO & MED CHEM AU 2023; 3:480-493. [PMID: 38144258 PMCID: PMC10739248 DOI: 10.1021/acsbiomedchemau.3c00043] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 06/28/2023] [Revised: 07/31/2023] [Accepted: 08/01/2023] [Indexed: 12/26/2023]
Abstract
Ribosomally produced and post-translationally modified polypeptides (RiPPs) are a diverse group of natural products that are processed by a variety of enzymes to their biologically relevant forms. PapB is a member of the radical S-adenosyl-l-methionine (rSAM) superfamily that introduces thioether cross-links between Cys and Asp residues in the PapA RiPP. We report that PapB has high tolerance for variations in the peptide substrate. Our results demonstrate that branched side chains in the thiol- and carboxylate-containing residues are processed and that lengthening of these groups to homocysteine and homoglutamate does not impair the ability of PapB to form thioether cross-links. Remarkably, the enzyme can even cross-link a peptide substrate where the native Asp carboxylate moiety is replaced with a tetrazole. We show that variations to residues embedded between the thiol- and carboxylate-containing residues are tolerated by PapB, as peptides containing both bulky (e.g., Phe) and charged (e.g., Lys) side chains in both natural L- and unnatural D-forms are efficiently cross-linked. Diastereomeric peptides bearing (2S,3R)- and (2S,3S)-methylaspartate are processed by PapB to form cyclic thioethers with markedly different rates, suggesting the enzymatic hydrogen atom abstraction event for the native Asp-containing substrate is diastereospecific. Finally, we synthesized two diastereomeric peptide substrates bearing E- and Z-configured γ,δ-dehydrohomoglutamate and show that PapB promotes addition of the deoxyadenosyl radical (dAdo•) instead of hydrogen atom abstraction. In the Z-configured γ,δ-dehydrohomoglutamate substrate, a fraction of the dAdo-adduct peptide is thioether cross-linked. In both cases, there is evidence for product inhibition of PapB, as the dAdo-adducts likely mimic the native transition state where dAdo• is poised to abstract a substrate hydrogen atom. Collectively, these findings provide critical insights into the arrangement of reacting species in the active site of the PapB, reveal unusual promiscuity, and highlight the potential of PapB as a tool in the development peptide therapeutics.
Collapse
Affiliation(s)
- Karsten
A. S. Eastman
- Department of Chemistry, University of Utah, 315 S. 1400 E, Salt Lake
City, Utah 84112, United States
| | - Marcus C. Mifflin
- Department of Chemistry, University of Utah, 315 S. 1400 E, Salt Lake
City, Utah 84112, United States
| | - Paul F. Oblad
- Department of Chemistry, University of Utah, 315 S. 1400 E, Salt Lake
City, Utah 84112, United States
| | - Andrew G. Roberts
- Department of Chemistry, University of Utah, 315 S. 1400 E, Salt Lake
City, Utah 84112, United States
| | - Vahe Bandarian
- Department of Chemistry, University of Utah, 315 S. 1400 E, Salt Lake
City, Utah 84112, United States
| |
Collapse
|
34
|
Omeiri J, Martin L, Usclat A, Cherrier MV, Nicolet Y. Maturation of the [FeFe]-Hydrogenase: Direct Transfer of the (κ 3 -cysteinate)Fe II (CN)(CO) 2 Complex B from HydG to HydE. Angew Chem Int Ed Engl 2023; 62:e202314819. [PMID: 37962296 DOI: 10.1002/anie.202314819] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/07/2023] [Revised: 11/13/2023] [Accepted: 11/14/2023] [Indexed: 11/15/2023]
Abstract
[FeFe]-hydrogenases efficiently catalyze the reversible oxidation of molecular hydrogen. Their prowess stems from the intricate H-cluster, combining a [Fe4 S4 ] center with a binuclear iron center ([2Fe]H ). In the latter, each iron atom is coordinated by a CO and CN ligand, connected by a CO and an azadithiolate ligand. The synthesis of this active site involves a unique multiprotein assembly, featuring radical SAM proteins HydG and HydE. HydG initiates the transformation of L-tyrosine into cyanide and carbon monoxide to generate complex B, which is subsequently transferred to HydE to continue the biosynthesis of the [2Fe]H -subcluster. Due to its instability, complex B isolation for structural or spectroscopic characterization has been elusive thus far. Nevertheless, the use of a biomimetic analogue of complex B allowed circumvention of the need for the HydG protein during in vitro functional investigations, implying a similar structure for complex B. Herein, we used the HydE protein as a nanocage to encapsulate and stabilize the complex B product generated by HydG. Using X-ray crystallography, we successfully determined its structure at 1.3 Å resolution. Furthermore, we demonstrated that complex B is directly transferred from HydG to HydE, thus not being released into the solution post-synthesis, highlighting a transient interaction between the two proteins.
Collapse
Affiliation(s)
- Juneina Omeiri
- Univ. Grenoble-Alpes, CEA, CNRS, IBS, Metalloproteins Unit, 38000, Grenoble, France
| | - Lydie Martin
- Univ. Grenoble-Alpes, CEA, CNRS, IBS, Metalloproteins Unit, 38000, Grenoble, France
| | - Anthony Usclat
- Univ. Grenoble-Alpes, CEA, CNRS, IBS, Metalloproteins Unit, 38000, Grenoble, France
| | - Mickael V Cherrier
- Univ. Grenoble-Alpes, CEA, CNRS, IBS, Metalloproteins Unit, 38000, Grenoble, France
| | - Yvain Nicolet
- Univ. Grenoble-Alpes, CEA, CNRS, IBS, Metalloproteins Unit, 38000, Grenoble, France
| |
Collapse
|
35
|
Lachowicz J, Lee J, Sagatova A, Jew K, Grove TL. The new epoch of structural insights into radical SAM enzymology. Curr Opin Struct Biol 2023; 83:102720. [PMID: 37862762 DOI: 10.1016/j.sbi.2023.102720] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/13/2023] [Revised: 09/21/2023] [Accepted: 09/22/2023] [Indexed: 10/22/2023]
Abstract
The Radical SAM (RS) superfamily of enzymes catalyzes a wide array of enzymatic reactions. The majority of these enzymes employ an electron from a reduced [4Fe-4S]+1 cluster to facilitate the reductive cleavage of S-adenosyl-l-methionine, thereby producing a highly reactive 5'-deoxyadenosyl radical (5'-dA⋅) and l-methionine. Typically, RS enzymes use this 5'-dA⋅ to extract a hydrogen atom from the target substrate, starting the cascade of an expansive and impressive variety of chemical transformations. While a great deal of understanding has been gleaned for 5'-dA⋅ formation, because of the chemical diversity within this superfamily, the subsequent chemical transformations have only been fully elucidated in a few examples. In addition, with the advent of new sequencing technology, the size of this family now surpasses 700,000 members, with the number of uncharacterized enzymes and domains also rapidly expanding. In this review, we outline the history of RS enzyme characterization in what we term "epochs" based on advances in technology designed for stably producing these enzymes in an active state. We propose that the state of the field has entered the fourth epoch, which we argue should commence with a protein structure initiative focused solely on RS enzymes to properly tackle this unique superfamily and uncover more novel chemical transformations that likely exist.
Collapse
Affiliation(s)
- Jake Lachowicz
- Department of Biochemistry, Albert Einstein College of Medicine, Bronx, NY 10461, USA
| | - James Lee
- Department of Biochemistry, Albert Einstein College of Medicine, Bronx, NY 10461, USA
| | - Alia Sagatova
- Department of Biochemistry, Albert Einstein College of Medicine, Bronx, NY 10461, USA
| | - Kristen Jew
- Department of Biochemistry, Albert Einstein College of Medicine, Bronx, NY 10461, USA
| | - Tyler L Grove
- Department of Biochemistry, Albert Einstein College of Medicine, Bronx, NY 10461, USA.
| |
Collapse
|
36
|
Benjdia A, Berteau O. B 12-dependent radical SAM enzymes: Ever expanding structural and mechanistic diversity. Curr Opin Struct Biol 2023; 83:102725. [PMID: 37931378 DOI: 10.1016/j.sbi.2023.102725] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/27/2023] [Revised: 09/26/2023] [Accepted: 10/03/2023] [Indexed: 11/08/2023]
Abstract
In the last decade, B12-dependent radical SAM enzymes have emerged as central biocatalysts in the biosynthesis of a myriad of natural products. Notably, these enzymes have been shown to catalyze carbon-carbon bond formation on unactivated carbon atoms leading to unusual methylations. Recently, structural studies have revealed unprecedented insights into the complex chemistry catalyzed by these enzymes. In this review, we cover recent advances in our understanding of B12-dependent radical SAM enzymes from a mechanistic and structural perspective. We discuss the unanticipated diversity of these enzymes which suggests evolutionary links between various biosynthetic and metabolic pathways from antibiotic to RiPP and methane biosynthesis.
Collapse
Affiliation(s)
- Alhosna Benjdia
- Université Paris-Saclay, INRAE, AgroParisTech, Micalis Institute, ChemSyBio, 78350, Jouy-en-Josas, France.
| | - Olivier Berteau
- Université Paris-Saclay, INRAE, AgroParisTech, Micalis Institute, ChemSyBio, 78350, Jouy-en-Josas, France.
| |
Collapse
|
37
|
Woodard AM, Peccati F, Navo CD, Jiménez-Osés G, Mitchell DA. Benzylic Radical Stabilization Permits Ether Formation During Darobactin Biosynthesis. BIORXIV : THE PREPRINT SERVER FOR BIOLOGY 2023:2023.11.29.569256. [PMID: 38076856 PMCID: PMC10705402 DOI: 10.1101/2023.11.29.569256] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Indexed: 12/22/2023]
Abstract
The Gram-negative selective antibiotic darobactin A has attracted interest owing to its intriguing fused bicyclic structure and unique mode of action. Biosynthetic studies have revealed that darobactin is a ribosomally synthesized and post-translationally modified peptide (RiPP). During maturation, the darobactin precursor peptide (DarA) is modified by a radical S-adenosyl methionine (rSAM)-dependent enzyme (DarE) to contain ether and C-C crosslinks. In this work, we describe the enzymatic tolerance of DarE using a panel of DarA variants, revealing that DarE can install the ether and C-C crosslinks independently and in different locations on DarA. These efforts produced 57 darobactin variants, 50 of which were enzymatically modified. Several new variants with fused bicyclic structures were characterized, including darobactin W3Y, which replaces tryptophan with tyrosine at the twice-modified central position, and darobactin K5F, which displays a fused diether ring pattern. Three additional darobactin variants contained fused diether macrocycles, leading us to investigate the origin of ether versus C-C crosslink formation. Computational analyses found that more stable and long-lived Cβ radicals found on aromatic amino acids correlated with ether formation. Further, molecular docking and calculated transition state structures provide support for the different indole connectivity observed for ether (Trp-C7) and C-C (Trp-C6) crosslink formation. We also provide experimental evidence for a β-oxotryptophan modification, a proposed intermediate during ether crosslink formation. Finally, mutational analysis of the DarA leader region and protein structural predictions identified which residues were dispensable for processing and others that govern substrate engagement by DarE. Our work informs on darobactin scaffold engineering and sheds additional light on the underlying principles of rSAM catalysis.
Collapse
Affiliation(s)
- Austin M. Woodard
- Department of Chemistry, University of Illinois at Urbana-Champaign, Urbana, Illinois 61801, USA
- Carl R. Woese Institute for Genomic Biology, University of Illinois at Urbana-Champaign, Urbana, Illinois 61801, USA
| | - Francesca Peccati
- Center for Cooperative Research in Biosciences (CIC bioGUNE), Basque Research and Technology Alliance (BRTA), Bizkaia Technology Park, Building 801A, 48160 Derio, Spain
| | - Claudio D. Navo
- Center for Cooperative Research in Biosciences (CIC bioGUNE), Basque Research and Technology Alliance (BRTA), Bizkaia Technology Park, Building 801A, 48160 Derio, Spain
| | - Gonzalo Jiménez-Osés
- Center for Cooperative Research in Biosciences (CIC bioGUNE), Basque Research and Technology Alliance (BRTA), Bizkaia Technology Park, Building 801A, 48160 Derio, Spain
- Ikerbasque, Basque Foundation for Science, 48013 Bilbao, Spain
| | - Douglas A. Mitchell
- Department of Chemistry, University of Illinois at Urbana-Champaign, Urbana, Illinois 61801, USA
- Carl R. Woese Institute for Genomic Biology, University of Illinois at Urbana-Champaign, Urbana, Illinois 61801, USA
- Department of Microbiology, University of Illinois at Urbana-Champaign, Urbana, Illinois 61801, USA
| |
Collapse
|
38
|
Lundahl MN, Yang H, Broderick WE, Hoffman BM, Broderick JB. Pyruvate formate-lyase activating enzyme: The catalytically active 5'-deoxyadenosyl radical caught in the act of H-atom abstraction. Proc Natl Acad Sci U S A 2023; 120:e2314696120. [PMID: 37956301 PMCID: PMC10665898 DOI: 10.1073/pnas.2314696120] [Citation(s) in RCA: 3] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/24/2023] [Accepted: 10/03/2023] [Indexed: 11/15/2023] Open
Abstract
Enzymes of the radical S-adenosyl-l-methionine (radical SAM, RS) superfamily, the largest in nature, catalyze remarkably diverse reactions initiated by H-atom abstraction. Glycyl radical enzyme activating enzymes (GRE-AEs) are a growing class of RS enzymes that generate the catalytically essential glycyl radical of GREs, which in turn catalyze essential reactions in anaerobic metabolism. Here, we probe the reaction of the GRE-AE pyruvate formate-lyase activating enzyme (PFL-AE) with the peptide substrate RVSG734YAV, which mimics the site of glycyl radical formation on the native substrate, pyruvate formate-lyase. Time-resolved freeze-quench electron paramagnetic resonance spectroscopy shows that at short mixing times reduced PFL-AE + SAM reacts with RVSG734YAV to form the central organometallic intermediate, Ω, in which the adenosyl 5'C is covalently bound to the unique iron of the [4Fe-4S] cluster. Freeze-trapping the reaction at longer times reveals the formation of the peptide G734• glycyl radical product. Of central importance, freeze-quenching at intermediate times reveals that the conversion of Ω to peptide glycyl radical is not concerted. Instead, homolysis of the Ω Fe-C5' bond generates the nominally "free" 5'-dAdo• radical, which is captured here by freeze-trapping. During cryoannealing at 77 K, the 5'-dAdo• directly abstracts an H-atom from the peptide to generate the G734• peptide radical trapped in the PFL-AE active site. These observations reveal the 5'-dAdo• radical to be a well-defined intermediate, caught in the act of substrate H-atom abstraction, providing new insights into the mechanistic steps of radical initiation by RS enzymes.
Collapse
Affiliation(s)
- Maike N. Lundahl
- Department of Chemistry and Biochemistry, Montana State University, Bozeman, MT59717
| | - Hao Yang
- Department of Chemistry, Northwestern University, Evanston, IL60208
| | - William E. Broderick
- Department of Chemistry and Biochemistry, Montana State University, Bozeman, MT59717
| | - Brian M. Hoffman
- Department of Chemistry, Northwestern University, Evanston, IL60208
| | - Joan B. Broderick
- Department of Chemistry and Biochemistry, Montana State University, Bozeman, MT59717
| |
Collapse
|
39
|
Ütkür K, Schmidt S, Mayer K, Klassen R, Brinkmann U, Schaffrath R. DPH1 Gene Mutations Identify a Candidate SAM Pocket in Radical Enzyme Dph1•Dph2 for Diphthamide Synthesis on EF2. Biomolecules 2023; 13:1655. [PMID: 38002337 PMCID: PMC10669111 DOI: 10.3390/biom13111655] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/24/2023] [Revised: 11/10/2023] [Accepted: 11/13/2023] [Indexed: 11/26/2023] Open
Abstract
In eukaryotes, the Dph1•Dph2 dimer is a non-canonical radical SAM enzyme. Using iron-sulfur (FeS) clusters, it cleaves the cosubstrate S-adenosyl-methionine (SAM) to form a 3-amino-3-carboxy-propyl (ACP) radical for the synthesis of diphthamide. The latter decorates a histidine residue on elongation factor 2 (EF2) conserved from archaea to yeast and humans and is important for accurate mRNA translation and protein synthesis. Guided by evidence from archaeal orthologues, we searched for a putative SAM-binding pocket in Dph1•Dph2 from Saccharomyces cerevisiae. We predict an SAM-binding pocket near the FeS cluster domain that is conserved across eukaryotes in Dph1 but not Dph2. Site-directed DPH1 mutagenesis and functional characterization through assay diagnostics for the loss of diphthamide reveal that the SAM pocket is essential for synthesis of the décor on EF2 in vivo. Further evidence from structural modeling suggests particularly critical residues close to the methionine moiety of SAM. Presumably, they facilitate a geometry specific for SAM cleavage and ACP radical formation that distinguishes Dph1•Dph2 from classical radical SAM enzymes, which generate canonical 5'-deoxyadenosyl (dAdo) radicals.
Collapse
Affiliation(s)
- Koray Ütkür
- Institut für Biologie, Fachgebiet Mikrobiologie, Universität Kassel, 34132 Kassel, Germany; (K.Ü.); (S.S.); (R.K.)
| | - Sarina Schmidt
- Institut für Biologie, Fachgebiet Mikrobiologie, Universität Kassel, 34132 Kassel, Germany; (K.Ü.); (S.S.); (R.K.)
| | - Klaus Mayer
- Roche Pharma Research and Early Development (pRED), Large Molecule Research, Roche Innovation Center Munich, 82377 Penzberg, Germany; (K.M.); (U.B.)
| | - Roland Klassen
- Institut für Biologie, Fachgebiet Mikrobiologie, Universität Kassel, 34132 Kassel, Germany; (K.Ü.); (S.S.); (R.K.)
| | - Ulrich Brinkmann
- Roche Pharma Research and Early Development (pRED), Large Molecule Research, Roche Innovation Center Munich, 82377 Penzberg, Germany; (K.M.); (U.B.)
| | - Raffael Schaffrath
- Roche Pharma Research and Early Development (pRED), Large Molecule Research, Roche Innovation Center Munich, 82377 Penzberg, Germany; (K.M.); (U.B.)
| |
Collapse
|
40
|
Key M, Baptista CG, Bergmann A, Floyd K, Blader IJ, Dou Z. Toxoplasma gondii harbors a hypoxia-responsive coproporphyrinogen dehydrogenase-like protein. BIORXIV : THE PREPRINT SERVER FOR BIOLOGY 2023:2023.11.16.567449. [PMID: 38014006 PMCID: PMC10680763 DOI: 10.1101/2023.11.16.567449] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/29/2023]
Abstract
Toxoplasma gondii is an apicomplexan parasite that is the cause of toxoplasmosis, a potentially lethal disease for immunocompromised individuals. During in vivo infection, the parasites encounter various growth environments, such as hypoxia. Therefore, the metabolic enzymes in the parasites must adapt to such changes to fulfill their nutritional requirements. Toxoplasma can de novo biosynthesize some nutrients, such as heme. The parasites heavily rely on their own heme production for intracellular survival. Notably, the antepenultimate step within this pathway is facilitated by coproporphyrinogen III oxidase (CPOX), which employs oxygen to convert coproporphyrinogen III to protoporphyrinogen IX through oxidative decarboxylation. Conversely, some bacteria can accomplish this conversion independently of oxygen through coproporphyrinogen dehydrogenase (CPDH). Genome analysis found a CPDH ortholog in Toxoplasma. The mutant Toxoplasma lacking CPOX displays significantly reduced growth, implying that TgCPDH potentially functions as an alternative enzyme to perform the same reaction as CPOX under low oxygen conditions. In this study, we demonstrated that TgCPDH exhibits coproporphyrinogen dehydrogenase activity by complementing it in a heme synthesis-deficient Salmonella mutant. Additionally, we observed an increase in TgCPDH expression in Toxoplasma when it grew under hypoxic conditions. However, deleting TgCPDH in both wildtype and heme-deficient parasites did not alter their intracellular growth under both ambient and low oxygen conditions. This research marks the first report of a coproporphyrinogen dehydrogenase-like protein in eukaryotic cells. Although TgCPDH responds to hypoxic conditions and possesses enzymatic activity, our findings suggest that it does not directly affect intracellular infection or the pathogenesis of Toxoplasma parasites.
Collapse
Affiliation(s)
- Melanie Key
- Department of Biological Sciences, Clemson University, Clemson, South Carolina, USA, 29634
- Eukaryotic Pathogens Innovation Center, Clemson University, Clemson, South Carolina, USA, 29634
| | - Carlos Gustavo Baptista
- Department of Microbiology and Immunology, University at Buffalo, The State University of New York, Buffalo, New York, USA 14260
| | - Amy Bergmann
- Department of Biological Sciences, Clemson University, Clemson, South Carolina, USA, 29634
| | - Katherine Floyd
- Department of Biological Sciences, Clemson University, Clemson, South Carolina, USA, 29634
| | - Ira J. Blader
- Department of Microbiology and Immunology, University at Buffalo, The State University of New York, Buffalo, New York, USA 14260
| | - Zhicheng Dou
- Department of Biological Sciences, Clemson University, Clemson, South Carolina, USA, 29634
- Eukaryotic Pathogens Innovation Center, Clemson University, Clemson, South Carolina, USA, 29634
| |
Collapse
|
41
|
Villarreal DG, Rao G, Tao L, Liu L, Rauchfuss TB, Britt RD. Characterizing the Biosynthesis of the [Fe(II)(CN)(CO) 2(cysteinate)] - Organometallic Product of the Radical-SAM Enzyme HydG by EPR and Mössbauer Spectroscopy. J Phys Chem B 2023; 127:9295-9302. [PMID: 37861415 DOI: 10.1021/acs.jpcb.3c05495] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/21/2023]
Abstract
[FeFe]-hydrogenases employ a catalytic H-cluster, consisting of a [4Fe-4S]H cluster linked to a [2Fe]H subcluster with CO, CN- ligands, and an azadithiolate bridge, which mediates the rapid redox interconversion of H+ and H2. In the biosynthesis of this H-cluster active site, the radical S-adenosyl-l-methionine (radical SAM, RS) enzyme HydG plays the crucial role of generating an organometallic [Fe(II)(CN)(CO)2(cysteinate)]- product that is en route to forming the H-cluster. Here, we report direct observation of this diamagnetic organometallic Fe(II) complex through Mössbauer spectroscopy, revealing an isomer shift of δ = 0.10 mm s-1 and quadrupole splitting of ΔEQ = 0.66 mm s-1. These Mössbauer values are a change from the starting values of δ = 1.15 mm s-1 and ΔEQ = 3.23 mm s-1 for the ferrous "dangler" Fe in HydG. These values of the observed product complex B are in good agreement with Mössbauer parameters for the low-spin Fe2+ ions in synthetic analogues, such as 57Fe Syn-B, which we report here. These results highlight the essential role that HydG plays in converting a resting-state high-spin Fe(II) to a low-spin organometallic Fe(II) product that can be transferred to the downstream maturase enzymes.
Collapse
Affiliation(s)
- David G Villarreal
- Department of Chemistry, University of California Davis, Davis, California 95616, United States
| | - Guodong Rao
- Department of Chemistry, University of California Davis, Davis, California 95616, United States
| | - Lizhi Tao
- Department of Chemistry, University of California Davis, Davis, California 95616, United States
| | - Liang Liu
- School of Chemical Sciences, University of Illinois at Urbana─Champaign, Urbana, Illinois 61801, United States
| | - Thomas B Rauchfuss
- School of Chemical Sciences, University of Illinois at Urbana─Champaign, Urbana, Illinois 61801, United States
| | - R David Britt
- Department of Chemistry, University of California Davis, Davis, California 95616, United States
| |
Collapse
|
42
|
Boucher DG, Nguyen ZA, Minteer SD. Exploring electrolyte effects on metal-alkyl bond stability: impact and implications for electrosynthesis. Faraday Discuss 2023; 247:147-158. [PMID: 37489255 DOI: 10.1039/d3fd00054k] [Citation(s) in RCA: 1] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 07/26/2023]
Abstract
Transition metal catalysis hinges on the formation of metal-carbon bonds during catalytic cycles. The stability and reactivity of these bonds are what determine product chemo-, regio-, and enantioselectivity. The advent of electrosynthetic methodologies has placed the current understanding of these metal-alkyl bonds into a new environment of charged species and electrochemically induced reactivity. In this paper, we explore the often neglected impact of supporting electrolyte on homogeneous electrocatalytic mechanisms using the catalytic reduction of benzyl chlorides via Co and Fe tetraphenylporphyrins as a model reaction. The mechanism of this reaction is confirmed to proceed through the formation of the metal-alkyl intermediates. Critically, the stability of these intermediates, in both the Co and Fe systems, is found to be affected by the hydrodynamic radius of the supporting electrolyte, leading to differences in electrolyte-solvent shell. These studies provide important information for the design of electrosynthetic reactions, and provide a starting point for the rational design of functional supporting electrolytes.
Collapse
Affiliation(s)
- Dylan G Boucher
- Department of Chemistry, University of Utah, Salt Lake City, UT, USA.
| | - Zachary A Nguyen
- Department of Chemistry, University of Utah, Salt Lake City, UT, USA.
| | - Shelley D Minteer
- Department of Chemistry, University of Utah, Salt Lake City, UT, USA.
| |
Collapse
|
43
|
Ma S, Xi W, Wang S, Chen H, Guo S, Mo T, Chen W, Deng Z, Chen F, Ding W, Zhang Q. Substrate-Controlled Catalysis in the Ether Cross-Link-Forming Radical SAM Enzymes. J Am Chem Soc 2023; 145:22945-22953. [PMID: 37769281 DOI: 10.1021/jacs.3c04355] [Citation(s) in RCA: 9] [Impact Index Per Article: 9.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 09/30/2023]
Abstract
Darobactin is a heptapeptide antibiotic featuring an ether cross-link and a C-C cross-link, and both cross-links are installed by a radical S-adenosylmethionine (rSAM) enzyme DarE. How a single DarE enzyme affords the two chemically distinct cross-links remains largely obscure. Herein, by mapping the biosynthetic landscape for darobactin-like RiPP (daropeptide), we identified and characterized two novel daropeptides that lack the C-C cross-link present in darobactin and instead are solely composed of ether cross-links. Phylogenetic and mutagenesis analyses reveal that the daropeptide maturases possess intrinsic multifunctionality, catalyzing not only the formation of ether cross-link but also C-C cross-linking and Ser oxidation. Intriguingly, the different chemical outcomes are controlled by the exact substrate motifs. Our work not only provides a roadmap for the discovery of new daropeptide natural products but also offers insights into the regulatory mechanisms that govern these remarkably versatile ether cross-link-forming rSAM enzymes.
Collapse
Affiliation(s)
- Suze Ma
- Department of Chemistry, Fudan University, Shanghai 200433, China
| | - Wenhui Xi
- Department of Chemistry, Fudan University, Shanghai 200433, China
| | - Shu Wang
- Department of Chemistry, Fudan University, Shanghai 200433, China
| | - Heng Chen
- Department of Chemistry, Fudan University, Shanghai 200433, China
| | - Sijia Guo
- State Key Laboratory of Microbial Metabolism, School of Life Sciences & Biotechnology, Shanghai Jiao Tong University, Shanghai 200240, China
| | - Tianlu Mo
- School of Health Science and Engineering, University of Shanghai for Science and Technology, Shanghai 200093, China
| | - Wenxue Chen
- Department of Chemistry, Fudan University, Shanghai 200433, China
| | - Zixin Deng
- State Key Laboratory of Microbial Metabolism, School of Life Sciences & Biotechnology, Shanghai Jiao Tong University, Shanghai 200240, China
| | - Fener Chen
- Department of Chemistry, Fudan University, Shanghai 200433, China
- National Engineering Research Center for Carbohydrate Synthesis, Jiangxi Normal University, Nanchang 330022, China
| | - Wei Ding
- State Key Laboratory of Microbial Metabolism, School of Life Sciences & Biotechnology, Shanghai Jiao Tong University, Shanghai 200240, China
| | - Qi Zhang
- Department of Chemistry, Fudan University, Shanghai 200433, China
| |
Collapse
|
44
|
Zhong G. Cytochromes P450 Associated with the Biosyntheses of Ribosomally Synthesized and Post-translationally Modified Peptides. ACS BIO & MED CHEM AU 2023; 3:371-388. [PMID: 37876494 PMCID: PMC10591300 DOI: 10.1021/acsbiomedchemau.3c00026] [Citation(s) in RCA: 3] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 04/25/2023] [Revised: 06/25/2023] [Accepted: 06/27/2023] [Indexed: 10/26/2023]
Abstract
Ribosomally synthesized and post-translationally modified peptides (RiPPs) are a class of exponentially increased natural products with characteristic chemical structures, topologies, and biosynthetic mechanisms as well as exceptional bioactivities including antibacteria, antitumors, and antiviruses. The biosynthesis of RiPP proceeds via a ribosomally assembled precursor peptide that undergoes varied post-translational modifications to generate a mature peptide. Cytochrome P450 (CYP or P450) monooxygenases are a superfamily of heme-containing enzymes that span a wide range of secondary metabolite biosynthetic pathways due to their broad substrate scopes and excellent catalytic versatility. In contrast to the enormous quantities of RiPPs and P450s, the P450 associated RiPP biosynthesis is comparatively limited, with most of their functions and timings remaining mysterious. Herein, this Review aims to provide an overview on the striking roles of P450s in RiPP biosyntheses uncovered to date and to illustrate their remarkable functions, mechanisms, as well as remaining challenges. This will shed light on novel P450 discovery and characterizations in RiPP biosyntheses.
Collapse
Affiliation(s)
- Guannan Zhong
- State
Key Laboratory of Microbial Technology, Shandong University, Qingdao 266237, China
- Suzhou
Research Institute of Shandong University, Suzhou 215123, China
| |
Collapse
|
45
|
Rao G, Yu X, Zhang Y, Rauchfuss TB, Britt RD. Fully Refined Semisynthesis of the [FeFe] Hydrogenase H-Cluster. Biochemistry 2023; 62:2868-2877. [PMID: 37691492 DOI: 10.1021/acs.biochem.3c00393] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 09/12/2023]
Abstract
[FeFe] hydrogenases contain a 6-Fe cofactor that serves as the active site for efficient redox interconversion between H2 and protons. The biosynthesis of the so-called H-cluster involves unusual enzymatic reactions that synthesize organometallic Fe complexes containing azadithiolate, CO, and CN- ligands. We have previously demonstrated that specific synthetic [Fe(CO)x(CN)y] complexes can be used to functionally replace proposed Fe intermediates in the maturation reaction. Here, we report the results from performing such cluster semisynthesis in the context of a recent fully defined cluster maturation procedure, which eliminates unknown components previously employed from Escherichia coli cell lysate and demonstrate this provides a concise route to H-cluster synthesis. We show that formaldehyde can be used as a simple reagent as the carbon source of the bridging adt ligand of H-cluster in lieu of serine/serine hydroxymethyltransferase. In addition to the actual H-cluster, we observe the formation of several H-cluster-like species, the identities of which are probed by cryogenic photolysis combined with EPR/ENDOR spectroscopy.
Collapse
Affiliation(s)
- Guodong Rao
- Department of Chemistry, University of California, Davis, Davis, California 95616, United States
| | - Xin Yu
- Department of Chemistry, University of Illinois at Urbana-Champaign, Urbana, Illinois 61820, United States
| | - Yu Zhang
- Department of Chemistry, University of Illinois at Urbana-Champaign, Urbana, Illinois 61820, United States
| | - Thomas B Rauchfuss
- Department of Chemistry, University of Illinois at Urbana-Champaign, Urbana, Illinois 61820, United States
| | - R David Britt
- Department of Chemistry, University of California, Davis, Davis, California 95616, United States
- Miller Institute for Basic Research in Science, University of California, Berkeley, Berkeley, California 94720, United States
| |
Collapse
|
46
|
Abstract
Covering: from 2000 up to the very early part of 2023S-Adenosyl-L-methionine (SAM) is a naturally occurring trialkyl sulfonium molecule that is typically associated with biological methyltransfer reactions. However, SAM is also known to donate methylene, aminocarboxypropyl, adenosyl and amino moieties during natural product biosynthetic reactions. The reaction scope is further expanded as SAM itself can be modified prior to the group transfer such that a SAM-derived carboxymethyl or aminopropyl moiety can also be transferred. Moreover, the sulfonium cation in SAM has itself been found to be critical for several other enzymatic transformations. Thus, while many SAM-dependent enzymes are characterized by a methyltransferase fold, not all of them are necessarily methyltransferases. Furthermore, other SAM-dependent enzymes do not possess such a structural feature suggesting diversification along different evolutionary lineages. Despite the biological versatility of SAM, it nevertheless parallels the chemistry of sulfonium compounds used in organic synthesis. The question thus becomes how enzymes catalyze distinct transformations via subtle differences in their active sites. This review summarizes recent advances in the discovery of novel SAM utilizing enzymes that rely on Lewis acid/base chemistry as opposed to radical mechanisms of catalysis. The examples are categorized based on the presence of a methyltransferase fold and the role played by SAM within the context of known sulfonium chemistry.
Collapse
Affiliation(s)
- Yu-Hsuan Lee
- Department of Chemistry, University of Texas at Austin, Austin, TX 78712, USA.
| | - Daan Ren
- Department of Chemistry, University of Texas at Austin, Austin, TX 78712, USA.
| | - Byungsun Jeon
- Department of Chemistry, University of Texas at Austin, Austin, TX 78712, USA.
| | - Hung-Wen Liu
- Department of Chemistry, University of Texas at Austin, Austin, TX 78712, USA.
- Division of Chemical Biology & Medicinal Chemistry, College of Pharmacy, University of Texas at Austin, Austin, TX 78712, USA
| |
Collapse
|
47
|
Dreishpoon MB, Bick NR, Petrova B, Warui DM, Cameron A, Booker SJ, Kanarek N, Golub TR, Tsvetkov P. FDX1 regulates cellular protein lipoylation through direct binding to LIAS. J Biol Chem 2023; 299:105046. [PMID: 37453661 PMCID: PMC10462841 DOI: 10.1016/j.jbc.2023.105046] [Citation(s) in RCA: 18] [Impact Index Per Article: 18.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/30/2023] [Revised: 07/03/2023] [Accepted: 07/05/2023] [Indexed: 07/18/2023] Open
Abstract
Ferredoxins are a family of iron-sulfur (Fe-S) cluster proteins that serve as essential electron donors in numerous cellular processes that are conserved through evolution. The promiscuous nature of ferredoxins as electron donors enables them to participate in many metabolic processes including steroid, heme, vitamin D, and Fe-S cluster biosynthesis in different organisms. However, the unique natural function(s) of each of the two human ferredoxins (FDX1 and FDX2) are still poorly characterized. We recently reported that FDX1 is both a crucial regulator of copper ionophore-induced cell death and serves as an upstream regulator of cellular protein lipoylation, a mitochondrial lipid-based post-translational modification naturally occurring on four mitochondrial enzymes that are crucial for TCA cycle function. Here we show that FDX1 directly regulates protein lipoylation by binding the lipoyl synthase (LIAS) enzyme promoting its functional binding to the lipoyl carrier protein GCSH and not through indirect regulation of cellular Fe-S cluster biosynthesis. Metabolite profiling revealed that the predominant cellular metabolic outcome of FDX1 loss of function is manifested through the regulation of the four lipoylation-dependent enzymes ultimately resulting in loss of cellular respiration and sensitivity to mild glucose starvation. Transcriptional profiling established that FDX1 loss-of-function results in the induction of both compensatory metabolism-related genes and the integrated stress response, consistent with our findings that FDX1 loss-of-function is conditionally lethal. Together, our findings establish that FDX1 directly engages with LIAS, promoting its role in cellular protein lipoylation, a process essential in maintaining cell viability under low glucose conditions.
Collapse
Affiliation(s)
| | - Nolan R Bick
- Broad Institute of Harvard and MIT, Cambridge, USA
| | - Boryana Petrova
- Harvard Medical School, Boston, Massachusetts, USA; Department of Pathology, Boston Children's Hospital, Boston, Massachusetts, USA
| | - Douglas M Warui
- Department of Chemistry and Biochemistry and Molecular Biology and the Howard Hughes Medical Institute, The Pennsylvania State University, State College, Pennsylvania, USA
| | | | - Squire J Booker
- Department of Chemistry and Biochemistry and Molecular Biology and the Howard Hughes Medical Institute, The Pennsylvania State University, State College, Pennsylvania, USA
| | - Naama Kanarek
- Broad Institute of Harvard and MIT, Cambridge, USA; Harvard Medical School, Boston, Massachusetts, USA; Department of Pathology, Boston Children's Hospital, Boston, Massachusetts, USA
| | - Todd R Golub
- Broad Institute of Harvard and MIT, Cambridge, USA; Harvard Medical School, Boston, Massachusetts, USA; Department of Pediatric Oncology, Dana Farber Cancer Institute, Boston, Massachusetts, USA; Division of Pediatric Hematology/Oncology, Boston Children's Hospital, Boston, Massachusetts, USA
| | | |
Collapse
|
48
|
Eastman KAS, Jochimsen AS, Bandarian V. Intermolecular electron transfer in radical SAM enzymes as a new paradigm for reductive activation. J Biol Chem 2023; 299:105058. [PMID: 37460016 PMCID: PMC10470005 DOI: 10.1016/j.jbc.2023.105058] [Citation(s) in RCA: 1] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/03/2023] [Revised: 07/10/2023] [Accepted: 07/13/2023] [Indexed: 08/26/2023] Open
Abstract
Radical S-adenosyl-L-methionine (rSAM) enzymes bind one or more Fe-S clusters and catalyze transformations that produce complex and structurally diverse natural products. One of the clusters, a 4Fe-4S cluster, binds and reductively cleaves SAM to generate the 5'-deoxyadenosyl radical, which initiates the catalytic cycle by H-atom transfer from the substrate. The role(s) of the additional auxiliary Fe-S clusters (ACs) remains largely enigmatic. The rSAM enzyme PapB catalyzes the formation of thioether cross-links between the β-carbon of an Asp and a Cys thiolate found in the PapA peptide. One of the two ACs in the protein binds to the substrate thiol where, upon formation of a thioether bond, one reducing equivalent is returned to the protein. However, for the next catalytic cycle to occur, the protein must undergo an electronic state isomerization, returning the electron to the SAM-binding cluster. Using a series of iron-sulfur cluster deletion mutants, our data support a model whereby the isomerization is an obligatorily intermolecular electron transfer event that can be mediated by redox active proteins or small molecules, likely via the second AC in PapB. Surprisingly, a mixture of FMN and NADPH is sufficient to support both the reductive and the isomerization steps. These findings lead to a new paradigm involving intermolecular electron transfer steps in the activation of rSAM enzymes that require multiple iron-sulfur clusters for turnover. The implications of these results for the biological activation of rSAM enzymes are discussed.
Collapse
Affiliation(s)
| | | | - Vahe Bandarian
- University of Utah, Department of Chemistry, Salt Lake City, Utah, USA.
| |
Collapse
|
49
|
Du Y, Thanapipatsiri A, Yokoyama K. Biosynthesis and Genome Mining Potentials of Nucleoside Natural Products. Chembiochem 2023; 24:e202300342. [PMID: 37357819 PMCID: PMC10530009 DOI: 10.1002/cbic.202300342] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/05/2023] [Revised: 06/20/2023] [Accepted: 06/22/2023] [Indexed: 06/27/2023]
Abstract
Nucleoside natural products show diverse biological activities and serve as leads for various application purposes, including human and veterinary medicine and agriculture. Studies in the past decade revealed that these nucleosides are biosynthesized through divergent mechanisms, in which early steps of the pathways can be classified into two types (C5' oxidation and C5' radical extension), while the structural diversity is created by downstream tailoring enzymes. Based on this biosynthetic logic, we investigated the genome mining discovery potentials of these nucleosides using the two enzymes representing the two types of C5' modifications: LipL-type α-ketoglutarate (α-KG) and Fe-dependent oxygenases and NikJ-type radical S-adenosyl-L-methionine (SAM) enzymes. The results suggest that this approach allows discovery of putative nucleoside biosynthetic gene clusters (BGCs) and the prediction of the core nucleoside structures. The results also revealed the distribution of these pathways in nature and implied the possibility of future genome mining discovery of novel nucleoside natural products.
Collapse
Affiliation(s)
- Yanan Du
- Department of Biochemistry, Duke University School of Medicine, 307 Research Drive, Durham, NC 27710, USA
| | - Anyarat Thanapipatsiri
- Department of Biochemistry, Duke University School of Medicine, 307 Research Drive, Durham, NC 27710, USA
| | - Kenichi Yokoyama
- Department of Biochemistry, Duke University School of Medicine, 307 Research Drive, Durham, NC 27710, USA
- Department of Chemistry, Duke University, 307 Research Drive, Durham, NC 27710, USA
| |
Collapse
|
50
|
Cheng B, Huang J, Duan Y, Liu W. Association of Radical Chemistry with LanD Flavoprotein Activity for C-Terminal Macrocyclization of a Ribosomal Peptide by Formation of an Unsaturated Thioether Residue. Angew Chem Int Ed Engl 2023; 62:e202308733. [PMID: 37431841 DOI: 10.1002/anie.202308733] [Citation(s) in RCA: 1] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/21/2023] [Revised: 07/10/2023] [Accepted: 07/11/2023] [Indexed: 07/12/2023]
Abstract
LanD flavoproteins catalyze oxidative decarboxylation of the C-terminal Cys residue of a peptide to produce an enethiol. This enethiol is highly reactive and can be coupled with an upstream dehydroamino acid through Michael addition to form S-[2-aminovinyl](3-methyl)cysteine, an unsaturated thioether residue known to be characteristic of an array of C-terminally macrocyclized, ribosomally synthesized and posttranslationally modified peptides (RiPPs). Based on a two-stage bioinformatics mining of posttranslational modifications (PTMs) related to C-terminal Cys processing, we report herein that LanD activity can couple with radical S-adenosylmethionine chemistry to provide a new unsaturated thioether residue, S-[2-aminovinyl]-3-carbamoylcysteine, by conjugating the resultant enethiol with Cβ of the Asn residue in the C-terminal NxxC motif of a peptide for macrocyclization. This study furthers our understanding of the variety of PTMs involved in creating the structure diversity of macrocyclic RiPPs.
Collapse
Affiliation(s)
- Botao Cheng
- State Key Laboratory of Bioorganic and Natural Products Chemistry, Center for Excellence in Molecular Synthesis, Shanghai Institute of Organic Chemistry, University of Chinese Academy of Sciences, 345 Lingling Road, Shanghai, 200032, China
| | - Jiwu Huang
- State Key Laboratory of Bioorganic and Natural Products Chemistry, Center for Excellence in Molecular Synthesis, Shanghai Institute of Organic Chemistry, University of Chinese Academy of Sciences, 345 Lingling Road, Shanghai, 200032, China
| | - Yuting Duan
- State Key Laboratory of Bioorganic and Natural Products Chemistry, Center for Excellence in Molecular Synthesis, Shanghai Institute of Organic Chemistry, University of Chinese Academy of Sciences, 345 Lingling Road, Shanghai, 200032, China
| | - Wen Liu
- State Key Laboratory of Bioorganic and Natural Products Chemistry, Center for Excellence in Molecular Synthesis, Shanghai Institute of Organic Chemistry, University of Chinese Academy of Sciences, 345 Lingling Road, Shanghai, 200032, China
| |
Collapse
|