1
|
Huang R, Zhi N, Yu L, Li Y, Wu X, He J, Zhu H, Qiao J, Liu X, Tian C, Wang J, Dong M. Genetically Encoded Photosensitizer Protein Reduces Iron–Sulfur Clusters of Radical SAM Enzymes. ACS Catal 2023. [DOI: 10.1021/acscatal.2c05143] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/07/2023]
Affiliation(s)
- Rongrong Huang
- Frontiers Science Center for Synthetic Biology, Key Laboratory of Systems Bioengineering (MOE), School of Chemical Engineering and Technology, Tianjin University, Tianjin 300072, China
| | - Ning Zhi
- Frontiers Science Center for Synthetic Biology, Key Laboratory of Systems Bioengineering (MOE), School of Chemical Engineering and Technology, Tianjin University, Tianjin 300072, China
| | - Lu Yu
- High Magnetic Field Laboratory, Chinese Academy of Sciences, Hefei, Anhui 230031, China
| | - Yaoyang Li
- Frontiers Science Center for Synthetic Biology, Key Laboratory of Systems Bioengineering (MOE), School of Chemical Engineering and Technology, Tianjin University, Tianjin 300072, China
| | - Xiangyu Wu
- Frontiers Science Center for Synthetic Biology, Key Laboratory of Systems Bioengineering (MOE), School of Chemical Engineering and Technology, Tianjin University, Tianjin 300072, China
| | - Jiale He
- Frontiers Science Center for Synthetic Biology, Key Laboratory of Systems Bioengineering (MOE), School of Chemical Engineering and Technology, Tianjin University, Tianjin 300072, China
| | - Hongji Zhu
- Frontiers Science Center for Synthetic Biology, Key Laboratory of Systems Bioengineering (MOE), School of Chemical Engineering and Technology, Tianjin University, Tianjin 300072, China
| | - Jianjun Qiao
- Frontiers Science Center for Synthetic Biology, Key Laboratory of Systems Bioengineering (MOE), School of Chemical Engineering and Technology, Tianjin University, Tianjin 300072, China
| | - Xiaohong Liu
- Laboratory of RNA Biology, Institute of Biophysics, Chinese Academy of Sciences, Beijing 100101, China
| | - Changlin Tian
- High Magnetic Field Laboratory, Chinese Academy of Sciences, Hefei, Anhui 230031, China
- The First Affiliated Hospital of USTC, School of Life Sciences, Division of Life Sciences and Medicine, Joint Center for Biological Analytical Chemistry, University of Science and Technology of China, Hefei, Anhui 230026, China
| | - Jiangyun Wang
- Laboratory of RNA Biology, Institute of Biophysics, Chinese Academy of Sciences, Beijing 100101, China
| | - Min Dong
- Frontiers Science Center for Synthetic Biology, Key Laboratory of Systems Bioengineering (MOE), School of Chemical Engineering and Technology, Tianjin University, Tianjin 300072, China
| |
Collapse
|
2
|
Nguyen TQ, Nicolet Y. Structure and Catalytic Mechanism of Radical SAM Methylases. Life (Basel) 2022; 12:1732. [PMID: 36362886 PMCID: PMC9692996 DOI: 10.3390/life12111732] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/23/2022] [Revised: 10/25/2022] [Accepted: 10/26/2022] [Indexed: 08/14/2023] Open
Abstract
Methyl transfer is essential in myriad biological pathways found across all domains of life. Unlike conventional methyltransferases that catalyze this reaction through nucleophilic substitution, many members of the radical S-adenosyl-L-methionine (SAM) enzyme superfamily use radical-based chemistry to methylate unreactive carbon centers. These radical SAM methylases reductively cleave SAM to generate a highly reactive 5'-deoxyadenosyl radical, which initiates a broad range of transformations. Recently, crystal structures of several radical SAM methylases have been determined, shedding light on the unprecedented catalytic mechanisms used by these enzymes to overcome the substantial activation energy barrier of weakly nucleophilic substrates. Here, we review some of the discoveries on this topic over the last decade, focusing on enzymes for which three-dimensional structures are available to identify the key players in the mechanisms, highlighting the dual function of SAM as a methyl donor and a 5'-deoxyadenosyl radical or deprotonating base source. We also describe the role of the protein matrix in orchestrating the reaction through different strategies to catalyze such challenging methylations.
Collapse
Affiliation(s)
| | - Yvain Nicolet
- Metalloproteins Unit, Univ. Grenoble Alpes, CEA, CNRS, IBS, F-38000 Grenoble, France
| |
Collapse
|
3
|
Jäger C, Croft AK. If It Is Hard, It Is Worth Doing: Engineering Radical Enzymes from Anaerobes. Biochemistry 2022; 62:241-252. [PMID: 36121716 PMCID: PMC9850924 DOI: 10.1021/acs.biochem.2c00376] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/02/2023]
Abstract
With a pressing need for sustainable chemistries, radical enzymes from anaerobes offer a shortcut for many chemical transformations and deliver highly sought-after functionalizations such as late-stage C-H functionalization, C-C bond formation, and carbon-skeleton rearrangements, among others. The challenges in handling these oxygen-sensitive enzymes are reflected in their limited industrial exploitation, despite what they may deliver. With an influx of structures and mechanistic understanding, the scope for designed radical enzymes to deliver wanted processes becomes ever closer. Combined with new advances in computational methods and workflows for these complex systems, the outlook for an increased use of radical enzymes in future processes is exciting.
Collapse
|
4
|
McLean JT, Benny A, Nolan MD, Swinand G, Scanlan EM. Cysteinyl radicals in chemical synthesis and in nature. Chem Soc Rev 2021; 50:10857-10894. [PMID: 34397045 DOI: 10.1039/d1cs00254f] [Citation(s) in RCA: 12] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/11/2022]
Abstract
Nature harnesses the unique properties of cysteinyl radical intermediates for a diverse range of essential biological transformations including DNA biosynthesis and repair, metabolism, and biological photochemistry. In parallel, the synthetic accessibility and redox chemistry of cysteinyl radicals renders them versatile reactive intermediates for use in a vast array of synthetic applications such as lipidation, glycosylation and fluorescent labelling of proteins, peptide macrocyclization and stapling, desulfurisation of peptides and proteins, and development of novel therapeutics. This review provides the reader with an overview of the role of cysteinyl radical intermediates in both chemical synthesis and biological systems, with a critical focus on mechanistic details. Direct insights from biological systems, where applied to chemical synthesis, are highlighted and potential avenues from nature which are yet to be explored synthetically are presented.
Collapse
Affiliation(s)
- Joshua T McLean
- Trinity Biomedical Sciences Institute, Trinity College Dublin, The University of Dublin, 152-160 Pearse St., Dublin, D02 R590, Ireland.
| | - Alby Benny
- Trinity Biomedical Sciences Institute, Trinity College Dublin, The University of Dublin, 152-160 Pearse St., Dublin, D02 R590, Ireland.
| | - Mark D Nolan
- Trinity Biomedical Sciences Institute, Trinity College Dublin, The University of Dublin, 152-160 Pearse St., Dublin, D02 R590, Ireland.
| | - Glenna Swinand
- Trinity Biomedical Sciences Institute, Trinity College Dublin, The University of Dublin, 152-160 Pearse St., Dublin, D02 R590, Ireland.
| | - Eoin M Scanlan
- Trinity Biomedical Sciences Institute, Trinity College Dublin, The University of Dublin, 152-160 Pearse St., Dublin, D02 R590, Ireland.
| |
Collapse
|
5
|
Benjdia A, Berteau O. Radical SAM Enzymes and Ribosomally-Synthesized and Post-translationally Modified Peptides: A Growing Importance in the Microbiomes. Front Chem 2021; 9:678068. [PMID: 34350157 PMCID: PMC8326336 DOI: 10.3389/fchem.2021.678068] [Citation(s) in RCA: 17] [Impact Index Per Article: 5.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/08/2021] [Accepted: 06/07/2021] [Indexed: 11/13/2022] Open
Abstract
To face the current antibiotic resistance crisis, novel strategies are urgently required. Indeed, in the last 30 years, despite considerable efforts involving notably high-throughput screening and combinatorial libraries, only few antibiotics have been launched to the market. Natural products have markedly contributed to the discovery of novel antibiotics, chemistry and drug leads, with more than half anti-infective and anticancer drugs approved by the FDA being of natural origin or inspired by natural products. Among them, thanks to their modular structure and simple biosynthetic logic, ribosomally synthesized and posttranslationally modified peptides (RiPPs) are promising scaffolds. In addition, recent studies have highlighted the pivotal role of RiPPs in the human microbiota which remains an untapped source of natural products. In this review, we report on recent developments in radical SAM enzymology and how these unique biocatalysts have been shown to install complex and sometimes unprecedented posttranslational modifications in RiPPs with a special focus on microbiome derived enzymes.
Collapse
Affiliation(s)
- Alhosna Benjdia
- Université Paris-Saclay, INRAE, AgroParisTech, Micalis Institute, ChemSyBio, Jouy-en-Josas, France
| | - Olivier Berteau
- Université Paris-Saclay, INRAE, AgroParisTech, Micalis Institute, ChemSyBio, Jouy-en-Josas, France
| |
Collapse
|
6
|
Joshi S, Fedoseyenko D, Sharma V, Nesbit MA, Britt RD, Begley TP. Menaquinone Biosynthesis: New Strategies to Trap Radical Intermediates in the MqnE-Catalyzed Reaction. Biochemistry 2021; 60:1642-1646. [PMID: 33999605 DOI: 10.1021/acs.biochem.1c00181] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/14/2022]
Abstract
Aminofutalosine synthase (MqnE) is a radical SAM enzyme that catalyzes the conversion of 3-((1-carboxyvinyl)oxy)benzoic acid to aminofutalosine during the futalosine-dependent menaquinone biosynthesis. In this Communication, we report the trapping of a radical intermediate in the MqnE-catalyzed reaction using sodium dithionite, molecular oxygen, or 5,5-dimethyl-1-pyrroline-N-oxide. These radical trapping strategies are potentially of general utility in the study of other radical SAM enzymes.
Collapse
Affiliation(s)
- Sumedh Joshi
- Department of Chemistry, Texas A&M University, College Station, Texas 77842, United States
| | - Dmytro Fedoseyenko
- Department of Chemistry, Texas A&M University, College Station, Texas 77842, United States
| | - Vishav Sharma
- Department of Chemistry, Texas A&M University, College Station, Texas 77842, United States
| | - Mark A Nesbit
- Department of Chemistry, University of California, Davis, Davis, California 95616, United States
| | - R David Britt
- Department of Chemistry, University of California, Davis, Davis, California 95616, United States
| | - Tadhg P Begley
- Department of Chemistry, Texas A&M University, College Station, Texas 77842, United States
| |
Collapse
|
7
|
Honarmand Ebrahimi K, Rowbotham JS, McCullagh J, James WS. Mechanism of Diol Dehydration by a Promiscuous Radical-SAM Enzyme Homologue of the Antiviral Enzyme Viperin (RSAD2). Chembiochem 2020; 21:1605-1612. [PMID: 31951306 DOI: 10.1002/cbic.201900776] [Citation(s) in RCA: 14] [Impact Index Per Article: 3.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/20/2019] [Indexed: 12/30/2022]
Abstract
3'-Deoxynucleotides are an important class of drugs because they interfere with the metabolism of nucleotides, and their incorporation into DNA or RNA terminates cell division and viral replication. These compounds are generally produced by multi-step chemical synthesis, and an enzyme with the ability to catalyse the removal of the 3'-deoxy group from different nucleotides has yet to be described. Here, using a combination of HPLC, HRMS and NMR spectroscopy, we demonstrate that a thermostable fungal radical S-adenosylmethionine (SAM) enzyme, with similarity to the vertebrate antiviral enzyme viperin (RSAD2), can catalyse the transformation of CTP, UTP and 5-bromo-UTP to their 3'-deoxy-3',4'-didehydro (ddh) analogues. We show that, unlike the fungal enzyme, human viperin only catalyses the transformation of CTP to ddhCTP. Using electron paramagnetic resonance spectroscopy and molecular docking and dynamics simulations in combination with mutagenesis studies, we provide insight into the origin of the unprecedented substrate promiscuity of the enzyme and the mechanism of dehydration of a nucleotide. Our findings highlight the evolution of substrate specificity in a member of the radical-SAM enzymes. We predict that our work will help in using a new class of the radical-SAM enzymes for the biocatalytic synthesis of 3'-deoxy nucleotide/nucleoside analogues.
Collapse
Affiliation(s)
- Kourosh Honarmand Ebrahimi
- Department of Chemistry, University of Oxford, Chemistry Research Laboratory, Mansfield Road, OX1 3TA, Oxford, UK
| | - Jack S Rowbotham
- Department of Chemistry, University of Oxford, Chemistry Research Laboratory, Mansfield Road, OX1 3TA, Oxford, UK
| | - James McCullagh
- Department of Chemistry, University of Oxford, Chemistry Research Laboratory, Mansfield Road, OX1 3TA, Oxford, UK
| | - William S James
- Sir William Dunn School of Pathology, University of Oxford, South Parks Road, OX1 3RE, Oxford, UK
| |
Collapse
|
8
|
Ruszczycky MW, Zhong A, Liu HW. Following the electrons: peculiarities in the catalytic cycles of radical SAM enzymes. Nat Prod Rep 2019; 35:615-621. [PMID: 29485151 DOI: 10.1039/c7np00058h] [Citation(s) in RCA: 30] [Impact Index Per Article: 6.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022]
Abstract
Radical SAM enzymes use S-adenosyl-l-methionine as an oxidant to initiate radical-mediated transformations that would otherwise not be possible with Lewis acid/base chemistry alone. These reactions are either redox neutral or oxidative leading to certain expectations regarding the role of SAM as either a reusable cofactor or the ultimate electron acceptor during each turnover. However, these expectations are frequently not realized resulting in fundamental questions regarding the redox handling and movement of electrons associated with these biological catalysts. Herein we provide a focused perspective on several of these questions and associated hypotheses with an emphasis on recently discovered radical SAM enzymes.
Collapse
Affiliation(s)
- Mark W Ruszczycky
- Division of Chemical Biology & Medicinal Chemistry, College of Pharmacy, University of Texas at Austin, USA.
| | | | | |
Collapse
|
9
|
Yokoyama K, Lilla EA. C-C bond forming radical SAM enzymes involved in the construction of carbon skeletons of cofactors and natural products. Nat Prod Rep 2018; 35:660-694. [PMID: 29633774 PMCID: PMC6051890 DOI: 10.1039/c8np00006a] [Citation(s) in RCA: 70] [Impact Index Per Article: 11.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022]
Abstract
Covering: up to the end of 2017 C-C bond formations are frequently the key steps in cofactor and natural product biosynthesis. Historically, C-C bond formations were thought to proceed by two electron mechanisms, represented by Claisen condensation in fatty acids and polyketide biosynthesis. These types of mechanisms require activated substrates to create a nucleophile and an electrophile. More recently, increasing number of C-C bond formations catalyzed by radical SAM enzymes are being identified. These free radical mediated reactions can proceed between almost any sp3 and sp2 carbon centers, allowing introduction of C-C bonds at unconventional positions in metabolites. Therefore, free radical mediated C-C bond formations are frequently found in the construction of structurally unique and complex metabolites. This review discusses our current understanding of the functions and mechanisms of C-C bond forming radical SAM enzymes and highlights their important roles in the biosynthesis of structurally complex, naturally occurring organic molecules. Mechanistic consideration of C-C bond formation by radical SAM enzymes identifies the significance of three key mechanistic factors: radical initiation, acceptor substrate activation and radical quenching. Understanding the functions and mechanisms of these characteristic enzymes will be important not only in promoting our understanding of radical SAM enzymes, but also for understanding natural product and cofactor biosynthesis.
Collapse
Affiliation(s)
- Kenichi Yokoyama
- Department of Biochemistry, Duke University Medical Center, Durham, NC 27710, USA.
| | | |
Collapse
|
10
|
Parent A, Benjdia A, Guillot A, Kubiak X, Balty C, Lefranc B, Leprince J, Berteau O. Mechanistic Investigations of PoyD, a Radical S-Adenosyl-l-methionine Enzyme Catalyzing Iterative and Directional Epimerizations in Polytheonamide A Biosynthesis. J Am Chem Soc 2018; 140:2469-2477. [PMID: 29253341 PMCID: PMC5824343 DOI: 10.1021/jacs.7b08402] [Citation(s) in RCA: 42] [Impact Index Per Article: 7.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
Abstract
Ribosomally synthesized and post-translationally modified peptides (RiPPs) are a growing family of bioactive peptides. Among RiPPs, the bacterial toxin polytheonamide A is characterized by a unique set of post-translational modifications catalyzed by novel radical S-adenosyl-l-methionine (SAM) enzymes. Here we show that the radical SAM enzyme PoyD catalyzes in vitro polytheonamide epimerization in a C-to-N directional manner. By combining mutagenesis experiments with labeling studies and investigating the enzyme substrate promiscuity, we deciphered in detail the mechanism of PoyD. We notably identified a critical cysteine residue as a likely key H atom donor and demonstrated that PoyD belongs to a distinct family of radical SAM peptidyl epimerases. In addition, our study shows that the core peptide directly influences the epimerization pattern allowing for production of peptides with unnatural epimerization patterns.
Collapse
Affiliation(s)
- Aubérie Parent
- Micalis Institute, ChemSyBio, INRA, AgroParisTech, Université Paris-Saclay , 78350 Jouy-en-Josas, France
| | - Alhosna Benjdia
- Micalis Institute, ChemSyBio, INRA, AgroParisTech, Université Paris-Saclay , 78350 Jouy-en-Josas, France
| | - Alain Guillot
- Micalis Institute, ChemSyBio, INRA, AgroParisTech, Université Paris-Saclay , 78350 Jouy-en-Josas, France
| | - Xavier Kubiak
- Micalis Institute, ChemSyBio, INRA, AgroParisTech, Université Paris-Saclay , 78350 Jouy-en-Josas, France
| | - Clémence Balty
- Micalis Institute, ChemSyBio, INRA, AgroParisTech, Université Paris-Saclay , 78350 Jouy-en-Josas, France
| | - Benjamin Lefranc
- Inserm U1239, PRIMACEN, University of Rouen Normandy , 76000 Rouen, France
| | - Jérôme Leprince
- Inserm U1239, PRIMACEN, University of Rouen Normandy , 76000 Rouen, France
| | - Olivier Berteau
- Micalis Institute, ChemSyBio, INRA, AgroParisTech, Université Paris-Saclay , 78350 Jouy-en-Josas, France
| |
Collapse
|
11
|
Benjdia A, Balty C, Berteau O. Radical SAM Enzymes in the Biosynthesis of Ribosomally Synthesized and Post-translationally Modified Peptides (RiPPs). Front Chem 2017; 5:87. [PMID: 29167789 PMCID: PMC5682303 DOI: 10.3389/fchem.2017.00087] [Citation(s) in RCA: 64] [Impact Index Per Article: 9.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/25/2017] [Accepted: 10/11/2017] [Indexed: 11/13/2022] Open
Abstract
Ribosomally-synthesized and post-translationally modified peptides (RiPPs) are a large and diverse family of natural products. They possess interesting biological properties such as antibiotic or anticancer activities, making them attractive for therapeutic applications. In contrast to polyketides and non-ribosomal peptides, RiPPs derive from ribosomal peptides and are post-translationally modified by diverse enzyme families. Among them, the emerging superfamily of radical SAM enzymes has been shown to play a major role. These enzymes catalyze the formation of a wide range of post-translational modifications some of them having no counterparts in living systems or synthetic chemistry. The investigation of radical SAM enzymes has not only illuminated unprecedented strategies used by living systems to tailor peptides into complex natural products but has also allowed to uncover novel RiPP families. In this review, we summarize the current knowledge on radical SAM enzymes catalyzing RiPP post-translational modifications and discuss their mechanisms and growing importance notably in the context of the human microbiota.
Collapse
Affiliation(s)
- Alhosna Benjdia
- Micalis Institute, ChemSyBio, INRA, AgroParisTech, Université Paris-Saclay, Jouy-en-Josas, France
| | - Clémence Balty
- Micalis Institute, ChemSyBio, INRA, AgroParisTech, Université Paris-Saclay, Jouy-en-Josas, France
| | - Olivier Berteau
- Micalis Institute, ChemSyBio, INRA, AgroParisTech, Université Paris-Saclay, Jouy-en-Josas, France
| |
Collapse
|
12
|
Yang L, Li L. Insights into the Activity Change of Spore Photoproduct Lyase Induced by Mutations at a Peripheral Glycine Residue. Front Chem 2017; 5:14. [PMID: 28401144 PMCID: PMC5368176 DOI: 10.3389/fchem.2017.00014] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/14/2016] [Accepted: 02/28/2017] [Indexed: 12/19/2022] Open
Abstract
UV radiation triggers the formation of 5-thyminyl-5,6-dihydrothymine, i.e., the spore photoproduct (SP), in the genomic DNA of bacterial endospores. These SPs, if not repaired in time, may lead to genome instability and cell death. SP is mainly repaired by spore photoproduct lyase (SPL) during spore outgrowth via an unprecedented protein-harbored radical transfer pathway that is composed of at least a cysteine and two tyrosine residues. This mechanism is consistent with the recently solved SPL structure that shows all three residues are located in proximity and thus able to participate in the radical transfer process during the enzyme catalysis. In contrast, an earlier in vivo mutational study identified a glycine to arginine mutation at the position 168 on the B. subtilis SPL that is >15 Å away from the enzyme active site. This mutation appears to abolish the enzyme activity because endospores carrying this mutant were sensitive to UV light. To understand the molecular basis for this rendered enzyme activity, we constructed two SPL mutations G168A and G168R, examined their repair of dinucleotide SP TpT, and found that both mutants exhibit reduced enzyme activity. Comparing with the wildtype (WT) SPL enzyme, the G168A mutant slows down the SP TpT repair by 3~4-fold while the G168R mutant by ~ 80-fold. Both mutants exhibit a smaller apparent (DV) kinetic isotope effect (KIE) but a bigger competitive (DV/K) KIE than that by the WT SPL. Moreover, the G168R mutant also produces a large portion of the abortive repair product TpT-[Formula: see text]; the formation of which indicates that cysteine 141 is no longer well positioned as the H-donor to the thymine allylic radical intermediate. All these data imply that the mutation at the remote glycine 168 residue alters the enzyme 3D structure, subsequently reducing the SPL activity by changing the positions of the essential amino acids involved in the radical transfer process.
Collapse
Affiliation(s)
- Linlin Yang
- Department of Chemistry and Chemical Biology, Indiana University-Purdue University IndianapolisIndianapolis, IN, USA
| | - Lei Li
- Department of Chemistry and Chemical Biology, Indiana University-Purdue University IndianapolisIndianapolis, IN, USA
- Department of Dermatology, Indiana University School of MedicineIndianapolis, IN, USA
| |
Collapse
|
13
|
Yang L, Jian Y, Setlow P, Li L. Spore photoproduct within DNA is a surprisingly poor substrate for its designated repair enzyme-The spore photoproduct lyase. DNA Repair (Amst) 2017; 53:31-42. [PMID: 28320593 DOI: 10.1016/j.dnarep.2016.11.005] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/01/2015] [Revised: 05/23/2016] [Accepted: 11/15/2016] [Indexed: 12/15/2022]
Abstract
DNA repair enzymes typically recognize their substrate lesions with high affinity to ensure efficient lesion repair. In UV irradiated endospores, a special thymine dimer, 5-thyminyl-5,6-dihydrothymine, termed the spore photoproduct (SP), is the dominant DNA photolesion, which is rapidly repaired during spore outgrowth mainly by spore photoproduct lyase (SPL) using an unprecedented protein-harbored radical transfer process. Surprisingly, our in vitro studies using SP-containing short oligonucleotides, pUC 18 plasmid DNA, and E. coli genomic DNA found that they are all poor substrates for SPL in general, exhibiting turnover numbers of 0.01-0.2min-1. The faster turnover numbers are reached under single turnover conditions, and SPL activity is low with oligonucleotide substrates at higher concentrations. Moreover, SP-containing oligonucleotides do not go past one turnover. In contrast, the dinucleotide SP TpT exhibits a turnover number of 0.3-0.4min-1, and the reaction may reach up to 10 turnovers. These observations distinguish SPL from other specialized DNA repair enzymes. To the best of our knowledge, SPL represents an unprecedented example of a major DNA repair enzyme that cannot effectively repair its substrate lesion within the normal DNA conformation adopted in growing cells. Factors such as other DNA binding proteins, helicases or an altered DNA conformation may cooperate with SPL to enable efficient SP repair in germinating spores. Therefore, both SP formation and SP repair are likely to be tightly controlled by the unique cellular environment in dormant and outgrowing spore-forming bacteria, and thus SP repair may be extremely slow in non-spore-forming organisms.
Collapse
Affiliation(s)
- Linlin Yang
- Department of Chemistry and Chemical Biology, Indiana University-Purdue University Indianapolis (IUPUI), 402 North Blackford Street, Indianapolis, IN 46202, United States
| | - Yajun Jian
- Department of Chemistry and Chemical Biology, Indiana University-Purdue University Indianapolis (IUPUI), 402 North Blackford Street, Indianapolis, IN 46202, United States
| | - Peter Setlow
- Department of Molecular Biology and Biophysics, UConn Health, Farmington, CT 06030, United States
| | - Lei Li
- Department of Chemistry and Chemical Biology, Indiana University-Purdue University Indianapolis (IUPUI), 402 North Blackford Street, Indianapolis, IN 46202, United States; Department of Dermatology, Indiana University School of Medicine, Indianapolis, IN 46202, United States.
| |
Collapse
|
14
|
Post-translational modification of ribosomally synthesized peptides by a radical SAM epimerase in Bacillus subtilis. Nat Chem 2017. [PMID: 28644475 DOI: 10.1038/nchem.2714] [Citation(s) in RCA: 75] [Impact Index Per Article: 10.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/06/2023]
Abstract
Ribosomally synthesized peptides are built out of L-amino acids, whereas D-amino acids are generally the hallmark of non-ribosomal synthetic processes. Here we show that the model bacterium Bacillus subtilis is able to produce a novel type of ribosomally synthesized and post-translationally modified peptide that contains D-amino acids, and which we propose to call epipeptides. We demonstrate that a two [4Fe-4S]-cluster radical S-adenosyl-L-methionine (SAM) enzyme converts L-amino acids into their D-counterparts by catalysing Cα-hydrogen-atom abstraction and using a critical cysteine residue as the hydrogen-atom donor. Unexpectedly, these D-amino acid residues proved to be essential for the activity of a peptide that induces the expression of LiaRS, a major component of the bacterial cell envelope stress-response system. Present in B. subtilis and in several members of the human microbiome, these epipeptides and radical SAM epimerases broaden the landscape of peptidyl structures accessible to living organisms.
Collapse
|
15
|
Berteau O, Benjdia A. DNA Repair by the Radical SAM Enzyme Spore Photoproduct Lyase: From Biochemistry to Structural Investigations. Photochem Photobiol 2017; 93:67-77. [DOI: 10.1111/php.12702] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/20/2016] [Accepted: 12/19/2016] [Indexed: 10/20/2022]
Affiliation(s)
- Olivier Berteau
- Micalis Institute; INRA; ChemSyBio; AgroParisTech; Université Paris-Saclay; Jouy-en-Josas France
| | - Alhosna Benjdia
- Micalis Institute; INRA; ChemSyBio; AgroParisTech; Université Paris-Saclay; Jouy-en-Josas France
| |
Collapse
|
16
|
Douki T, von Koschembahr A, Cadet J. Insight in DNA Repair of UV-induced Pyrimidine Dimers by Chromatographic Methods. Photochem Photobiol 2017; 93:207-215. [PMID: 27935042 DOI: 10.1111/php.12685] [Citation(s) in RCA: 22] [Impact Index Per Article: 3.1] [Reference Citation Analysis] [Abstract] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/06/2016] [Accepted: 11/21/2016] [Indexed: 01/15/2023]
Abstract
UV-induced formation of pyrimidine dimers in DNA is a major deleterious event in both eukaryotic and prokaryotic cells. Accumulation of cyclobutane pyrimidine dimers and pyrimidine (6-4) pyrimidone photoproducts can lead to cell death or be at the origin of mutations. In skin, UV induction of DNA damage is a major initiating event in tumorigenesis. To counteract these deleterious effects, all cell types possess DNA repair machinery, such as nucleotide excision repair and, in some cell types, direct reversion. Different analytical approaches were used to assess the efficiency of repair and decipher the enzymatic mechanisms. We presently review the information provided by chromatographic methods, which are complementary to biochemical assays, such as immunological detection and electrophoresis-based techniques. Chromatographic assays are interesting in their ability to provide quantitative data on a wide range of damage and are also valuable tools for the identification of repair intermediates.
Collapse
Affiliation(s)
- Thierry Douki
- Univ. Grenoble Alpes, INAC, LCIB, LAN, Grenoble, France.,CEA, INAC, SyMMES, LAN, Grenoble, France
| | - Anne von Koschembahr
- Univ. Grenoble Alpes, INAC, LCIB, LAN, Grenoble, France.,CEA, INAC, SyMMES, LAN, Grenoble, France
| | - Jean Cadet
- Département de Médecine Nucléaire et Radiobiologie, Faculté de Médecine, Université de Sherbrooke, Sherbrooke, QC, Canada
| |
Collapse
|
17
|
Yang L, Adhikari J, Gross ML, Li L. Kinetic Isotope Effects and Hydrogen/Deuterium Exchange Reveal Large Conformational Changes During the Catalysis of the Clostridium acetobutylicum Spore Photoproduct Lyase. Photochem Photobiol 2017; 93:331-342. [PMID: 27992649 PMCID: PMC5315627 DOI: 10.1111/php.12697] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/25/2016] [Accepted: 11/29/2016] [Indexed: 11/30/2022]
Abstract
Spore photoproduct lyase (SPL) catalyzes the direct reversal of a thymine dimer 5-thyminyl-5,6-dihydrothymine (i.e. the spore photoproduct (SP)) to two thymine residues in germinating endospores. Previous studies suggest that SPL from the bacterium Bacillus subtilis (Bs) harbors an unprecedented radical-transfer pathway starting with cysteine 141 proceeding through tyrosine 99. However, in SPL from the bacterium Clostridium acetobutylicum (Ca), the cysteine (at position 74) and the tyrosine are located on the opposite sides of a substrate-binding pocket that has to collapse to bring the two residues into proximity, enabling the C→Y radical passage as implied in SPL(Bs) . To test this hypothesis, we adopted hydrogen/deuterium exchange mass spectrometry (HDX-MS) to show that C74(Ca) is located at a highly flexible region. The repair of dinucleotide SP TpT by SPL(Ca) is eight-fold to 10-fold slower than that by SPL(Bs) ; the process also generates a large portion of the aborted product TpTSO2- . SPL(Ca) exhibits apparent (D V) kinetic isotope effects (KIEs) of ~6 and abnormally large competitive (D V/K) KIEs (~20), both of which are much larger than the KIEs observed for SPL(Bs) . All these observations indicate that SPL(Ca) possesses a flexible active site and readily undergoes conformational changes during catalysis.
Collapse
Affiliation(s)
- Linlin Yang
- Department of Chemistry and Chemical Biology, Indiana University-Purdue University Indianapolis (IUPUI), 402 North Blackford Street, Indianapolis, Indiana, 46202, USA
| | - Jagat Adhikari
- Department of Chemistry, Washington University in St. Louis, One Brookings Dr., St. Louis, MO 63130, USA
| | - Michael L. Gross
- Department of Chemistry, Washington University in St. Louis, One Brookings Dr., St. Louis, MO 63130, USA
| | - Lei Li
- Department of Chemistry and Chemical Biology, Indiana University-Purdue University Indianapolis (IUPUI), 402 North Blackford Street, Indianapolis, Indiana, 46202, USA
- Department of Biochemistry and Molecular Biology & Department of Dermatology, Indiana University School of Medicine, Indianapolis, Indiana 46202, USA
| |
Collapse
|
18
|
Heidinger L, Kneuttinger AC, Kashiwazaki G, Weber S, Carell T, Schleicher E. Direct observation of a deoxyadenosyl radical in an active enzyme environment. FEBS Lett 2016; 590:4489-4494. [PMID: 27878994 DOI: 10.1002/1873-3468.12498] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/26/2016] [Revised: 11/16/2016] [Accepted: 11/17/2016] [Indexed: 11/11/2022]
Abstract
5'-deoxyadenosyl radicals have been proposed as the first common intermediate in the molecular reaction mechanism of the family of radical S-adenosyl-l-methionine (SAM) enzymes. However, this radical species has not yet been directly observed in a catalytically active enzyme environment. In a reduced and SAM-containing C140A mutant of the spore photoproduct lyase from Geobacillus thermodenitrificans, a mutant with altered catalytic activity, we were able to identify an organic radical with pronounced hyperfine structure using electron paramagnetic resonance spectroscopy. Guided by quantum-chemical computations at the density functional theory level of theory, this radical could be tentatively assigned to a deoxyadenosyl radical, which provides first experimental evidence for this intermediate in the reaction mechanism of radical SAM enzymes.
Collapse
Affiliation(s)
- Lorenz Heidinger
- Institut für Physikalische Chemie, Albert-Ludwigs-Universität Freiburg, Germany
| | - Andrea C Kneuttinger
- Department für Chemie, Ludwig-Maximilians-Universität München, Germany.,Institute of Biophysics and Physical Biochemistry, University of Regensburg, Germany
| | - Gengo Kashiwazaki
- Department für Chemie, Ludwig-Maximilians-Universität München, Germany
| | - Stefan Weber
- Institut für Physikalische Chemie, Albert-Ludwigs-Universität Freiburg, Germany
| | - Thomas Carell
- Department für Chemie, Ludwig-Maximilians-Universität München, Germany
| | - Erik Schleicher
- Institut für Physikalische Chemie, Albert-Ludwigs-Universität Freiburg, Germany
| |
Collapse
|
19
|
Bhandari DM, Fedoseyenko D, Begley TP. Tryptophan Lyase (NosL): A Cornucopia of 5′-Deoxyadenosyl Radical Mediated Transformations. J Am Chem Soc 2016; 138:16184-16187. [DOI: 10.1021/jacs.6b06139] [Citation(s) in RCA: 37] [Impact Index Per Article: 4.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/30/2022]
Affiliation(s)
- Dhananjay M. Bhandari
- Department of Chemistry, Texas A&M University, College Station, Texas 77843, United States
| | - Dmytro Fedoseyenko
- Department of Chemistry, Texas A&M University, College Station, Texas 77843, United States
| | - Tadhg P. Begley
- Department of Chemistry, Texas A&M University, College Station, Texas 77843, United States
| |
Collapse
|
20
|
Sulfatases and radical SAM enzymes: emerging themes in glycosaminoglycan metabolism and the human microbiota. Biochem Soc Trans 2016; 44:109-15. [PMID: 26862195 DOI: 10.1042/bst20150191] [Citation(s) in RCA: 30] [Impact Index Per Article: 3.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/05/2023]
Abstract
Humans live in a permanent association with bacterial populations collectively called the microbiota. In the last 10 years, major advances in our knowledge of the microbiota have shed light on its critical roles in human physiology. The microbiota has also been shown to be a major factor in numerous pathologies including obesity or inflammatory disorders. Despite tremendous progresses, our understanding of the key functions of the human microbiota and the molecular basis of its interactions with the host remain still poorly understood. Among the factors involved in host colonization, two enzymes families, sulfatases and radical S-adenosyl-L-methionine enzymes, have recently emerged as key enzymes.
Collapse
|
21
|
Hayes EC, Jian Y, Li L, Stoll S. EPR Study of UV-Irradiated Thymidine Microcrystals Supports Radical Intermediates in Spore Photoproduct Formation. J Phys Chem B 2016; 120:10923-10931. [DOI: 10.1021/acs.jpcb.6b06587] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/24/2022]
Affiliation(s)
- Ellen C. Hayes
- Department
of Chemistry, Box 351700, University of Washington, Seattle, Washington 98195, United States
| | - Yajun Jian
- Department
of Chemistry and Chemical Biology, 402 N. Blackford Street, LD 326, Indiana University—Purdue University Indianapolis, Indianapolis, Indiana 46202, United States
| | - Lei Li
- Department
of Chemistry and Chemical Biology, 402 N. Blackford Street, LD 326, Indiana University—Purdue University Indianapolis, Indianapolis, Indiana 46202, United States
| | - Stefan Stoll
- Department
of Chemistry, Box 351700, University of Washington, Seattle, Washington 98195, United States
| |
Collapse
|
22
|
Dong M, Horitani M, Dzikovski B, Pandelia ME, Krebs C, Freed JH, Hoffman BM, Lin H. Organometallic Complex Formed by an Unconventional Radical S-Adenosylmethionine Enzyme. J Am Chem Soc 2016; 138:9755-8. [PMID: 27465315 DOI: 10.1021/jacs.6b04155] [Citation(s) in RCA: 21] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/14/2023]
Abstract
Pyrococcus horikoshii Dph2 (PhDph2) is an unusual radical S-adenosylmethionine (SAM) enzyme involved in the first step of diphthamide biosynthesis. It catalyzes the reaction by cleaving SAM to generate a 3-amino-3-carboxypropyl (ACP) radical. To probe the reaction mechanism, we synthesized a SAM analogue (SAMCA), in which the ACP group of SAM is replaced with a 3-carboxyallyl group. SAMCA is cleaved by PhDph2, yielding a paramagnetic (S = 1/2) species, which is assigned to a complex formed between the reaction product, α-sulfinyl-3-butenoic acid, and the [4Fe-4S] cluster. Electron-nuclear double resonance (ENDOR) measurements with (13)C and (2)H isotopically labeled SAMCA support a π-complex between the C═C double bond of α-sulfinyl-3-butenoic acid and the unique iron of the [4Fe-4S] cluster. This is the first example of a radical SAM-related [4Fe-4S](+) cluster forming an organometallic complex with an alkene, shedding additional light on the mechanism of PhDph2 and expanding our current notions for the reactivity of [4Fe-4S] clusters in radical SAM enzymes.
Collapse
Affiliation(s)
- Min Dong
- Department of Chemistry and Chemical Biology, Cornell University , Ithaca, New York 14853, United States
| | - Masaki Horitani
- Department of Chemistry, Northwestern University , Evanston, Illinois 60208, United States
| | - Boris Dzikovski
- Department of Chemistry and Chemical Biology, Cornell University , Ithaca, New York 14853, United States
| | - Maria-Eirini Pandelia
- Department of Biochemistry, Brandeis University , Waltham, Massachusetts 02453, United States
| | - Carsten Krebs
- Department of Chemistry and Department of Biochemistry and Molecular Biology, The Pennsylvania State University , University Park, Pennsylvania 16802, United States
| | - Jack H Freed
- Department of Chemistry and Chemical Biology, Cornell University , Ithaca, New York 14853, United States
| | - Brian M Hoffman
- Department of Chemistry, Northwestern University , Evanston, Illinois 60208, United States
| | - Hening Lin
- Department of Chemistry and Chemical Biology, Cornell University , Ithaca, New York 14853, United States.,Howard Hughes Medical Institute, Cornell University , Ithaca, New York 14853, United States
| |
Collapse
|
23
|
Setlow P, Li L. Photochemistry and Photobiology of the Spore Photoproduct: A 50-Year Journey. Photochem Photobiol 2015; 91:1263-90. [PMID: 26265564 PMCID: PMC4631623 DOI: 10.1111/php.12506] [Citation(s) in RCA: 38] [Impact Index Per Article: 4.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/05/2015] [Accepted: 07/21/2015] [Indexed: 02/06/2023]
Abstract
Fifty years ago, a new thymine dimer was discovered as the dominant DNA photolesion in UV-irradiated bacterial spores [Donnellan, J. E. & Setlow R. B. (1965) Science, 149, 308-310], which was later named the spore photoproduct (SP). Formation of SP is due to the unique environment in the spore core that features low hydration levels favoring an A-DNA conformation, high levels of calcium dipicolinate that acts as a photosensitizer, and DNA saturation with small, acid-soluble proteins that alters DNA structure and reduces side reactions. In vitro studies reveal that any of these factors alone can promote SP formation; however, SP formation is usually accompanied by the production of other DNA photolesions. Therefore, the nearly exclusive SP formation in spores is due to the combined effects of these three factors. Spore photoproduct photoreaction is proved to occur via a unique H-atom transfer mechanism between the two involved thymine residues. Successful incorporation of SP into an oligonucleotide has been achieved via organic synthesis, which enables structural studies that reveal minor conformational changes in the SP-containing DNA. Here, we review the progress on SP photochemistry and photobiology in the past 50 years, which indicates a very rich SP photobiology that may exist beyond endospores.
Collapse
Affiliation(s)
- Peter Setlow
- Department of Molecular Biology and Biophysics, UConn Health, Farmington, Connecticut, USA
| | - Lei Li
- Department of Chemistry and Chemical Biology, Indiana University-Purdue University Indianapolis (IUPUI), Indianapolis, Indiana, 46202
- Department of Biochemistry and Molecular Biology & Department of Dermatology, Indiana University School of Medicine, Indianapolis, Indiana 46202
| |
Collapse
|
24
|
Benjdia A, Heil K, Winkler A, Carell T, Schlichting I. Rescuing DNA repair activity by rewiring the H-atom transfer pathway in the radical SAM enzyme, spore photoproduct lyase. Chem Commun (Camb) 2015; 50:14201-4. [PMID: 25285338 DOI: 10.1039/c4cc05158k] [Citation(s) in RCA: 16] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022]
Abstract
The radical SAM enzyme, spore photoproduct lyase, requires an H-atom transfer (HAT) pathway to catalyze DNA repair. By rational engineering, we demonstrate that it is possible to rewire its HAT pathway, a first step toward the development of novel catalysts based on the radical SAM enzyme scaffold.
Collapse
Affiliation(s)
- Alhosna Benjdia
- Department of Biomolecular Mechanisms, Max-Planck Institute for Medical Research, Jahnstrasse 29, 69120 Heidelberg, Germany
| | | | | | | | | |
Collapse
|
25
|
Ko Y, Ruszczycky MW, Choi SH, Liu HW. Mechanistic studies of the radical S-adenosylmethionine enzyme DesII with TDP-D-fucose. Angew Chem Int Ed Engl 2015; 54:860-3. [PMID: 25418063 PMCID: PMC4293265 DOI: 10.1002/anie.201409540] [Citation(s) in RCA: 22] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/26/2014] [Indexed: 11/06/2022]
Abstract
DesII is a radical S-adenosylmethionine (SAM) enzyme that catalyzes the C4-deamination of TDP-4-amino-4,6-dideoxyglucose through a C3 radical intermediate. However, if the C4 amino group is replaced with a hydroxy group (to give TDP-quinovose), the hydroxy group at C3 is oxidized to a ketone with no C4-dehydration. It is hypothesized that hyperconjugation between the C4 C-N/O bond and the partially filled p orbital at C3 of the radical intermediate modulates the degree to which elimination competes with dehydrogenation. To investigate this hypothesis, the reaction of DesII with the C4-epimer of TDP-quinovose (TDP-fucose) was examined. The reaction primarily results in the formation of TDP-6-deoxygulose and likely regeneration of TDP-fucose. The remainder of the substrate radical partitions roughly equally between C3-dehydrogenation and C4-dehydration. Thus, changing the stereochemistry at C4 permits a more balanced competition between elimination and dehydrogenation.
Collapse
Affiliation(s)
- Yeonjin Ko
- Division of Medicinal Chemistry, College of Pharmacy, and Department of Chemistry, University of Texas at Austin, Austin, Texas 78712, United States
| | - Mark W. Ruszczycky
- Division of Medicinal Chemistry, College of Pharmacy, and Department of Chemistry, University of Texas at Austin, Austin, Texas 78712, United States
| | - Sei-Hyun Choi
- Division of Medicinal Chemistry, College of Pharmacy, and Department of Chemistry, University of Texas at Austin, Austin, Texas 78712, United States
| | - Hung-wen Liu
- Division of Medicinal Chemistry, College of Pharmacy, and Department of Chemistry, University of Texas at Austin, Austin, Texas 78712, United States
| |
Collapse
|
26
|
Abstract
Spore photoproduct lyase (SPL) repairs 5-thyminyl-5,6-dihydrothymine, a thymine dimer that is also called the spore photoproduct (SP), in germinating endospores. SPL is a radical S-adenosylmethionine (SAM) enzyme, utilizing the 5'-deoxyadenosyl radical generated by SAM reductive cleavage reaction to revert SP to two thymine residues. Here we review the current progress in SPL mechanistic studies. Protein radicals are known to be involved in SPL catalysis; however, how these radicals are quenched to close the catalytic cycle is under debate.
Collapse
Affiliation(s)
- Linlin Yang
- From the Department of Chemistry and Chemical Biology, Indiana University-Purdue University Indianapolis (IUPUI), Indianapolis, Indiana, 46202 and
| | - Lei Li
- From the Department of Chemistry and Chemical Biology, Indiana University-Purdue University Indianapolis (IUPUI), Indianapolis, Indiana, 46202 and Department of Biochemistry and Molecular Biology, Indiana University School of Medicine (IUSM), Indianapolis, Indiana 46202
| |
Collapse
|
27
|
Ko Y, Ruszczycky MW, Choi SH, Liu HW. Mechanistic Studies of the RadicalS-Adenosylmethionine Enzyme DesII with TDP-D-Fucose. Angew Chem Int Ed Engl 2014. [DOI: 10.1002/ange.201409540] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/11/2022]
|
28
|
Wang J, Woldring RP, Román-Meléndez GD, McClain AM, Alzua BR, Marsh ENG. Recent advances in radical SAM enzymology: new structures and mechanisms. ACS Chem Biol 2014; 9:1929-38. [PMID: 25009947 PMCID: PMC4168785 DOI: 10.1021/cb5004674] [Citation(s) in RCA: 55] [Impact Index Per Article: 5.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/03/2023]
Abstract
![]()
The radical S-adenosylmethionine
(SAM) superfamily of enzymes catalyzes
an amazingly diverse variety of reactions ranging from simple hydrogen
abstraction to complicated multistep rearrangements and insertions.
The reactions they catalyze are important for a broad range of biological
functions, including cofactor and natural product biosynthesis, DNA
repair, and tRNA modification. Generally conserved features of the
radical SAM superfamily include a CX3CX2C motif
that binds an [Fe4S4] cluster essential for
the reductive cleavage of SAM. Here, we review recent advances in
our understanding of the structure and mechanisms of these enzymes
that, in some cases, have overturned widely accepted mechanisms.
Collapse
Affiliation(s)
- Jiarui Wang
- Department
of Chemistry, University of Michigan, Ann Arbor, Michigan 48109, United States
| | - Rory P. Woldring
- Department
of Chemistry, University of Michigan, Ann Arbor, Michigan 48109, United States
| | | | - Alan M. McClain
- Department
of Chemistry, University of Michigan, Ann Arbor, Michigan 48109, United States
| | - Brian R. Alzua
- Department
of Chemistry, University of Michigan, Ann Arbor, Michigan 48109, United States
| | - E. Neil G. Marsh
- Department
of Chemistry, University of Michigan, Ann Arbor, Michigan 48109, United States
| |
Collapse
|
29
|
Ames DM, Lin G, Jian Y, Cadet J, Li L. Unusually large deuterium discrimination during spore photoproduct formation. J Org Chem 2014; 79:4843-51. [PMID: 24820206 PMCID: PMC4049236 DOI: 10.1021/jo500775b] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/12/2022]
Abstract
The deuterium-labeling strategy has been widely used and proved highly effective in mechanistic investigation of chemical and biochemical reactions. However, it is often hampered by the incomplete label transfer, which subsequently obscures the mechanistic conclusion. During the study of photoinduced generation of 5-thyminyl-5,6-dihydrothymine, which is commonly called the spore photoproduct (SP), the Cadet laboratory found an incomplete (~67%) deuterium transfer in SP formation, which contrasts to the exclusive transfer observed by the Li laboratory. Here, we investigated this discrepancy by re-examining the SP formation using d3-thymidine. We spiked the d3-thymidine with varying amounts of unlabeled thymidine before the SP photochemistry is performed. Strikingly, our data show that the reaction is highly sensitive to the trace protiated thymidine in the starting material. As many as 17-fold enrichment is detected in the formed SP, which may explain the previously observed one-third protium incorporation. Although commercially available deuterated reagents are generally satisfactory as mechanistic probes, our results argue that attention is still needed to the possible interference from the trace protiated impurity, especially when the reaction yield is low and large isotopic discrimination is involved.
Collapse
Affiliation(s)
- David M Ames
- Department of Chemistry and Chemical Biology, Indiana University-Purdue University Indianapolis (IUPUI) , 402 North Blackford Street, Indianapolis, Indiana 46202, United States
| | | | | | | | | |
Collapse
|
30
|
Broderick JB, Duffus B, Duschene KS, Shepard EM. Radical S-adenosylmethionine enzymes. Chem Rev 2014; 114:4229-317. [PMID: 24476342 PMCID: PMC4002137 DOI: 10.1021/cr4004709] [Citation(s) in RCA: 589] [Impact Index Per Article: 58.9] [Reference Citation Analysis] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/25/2013] [Indexed: 12/22/2022]
Affiliation(s)
- Joan B. Broderick
- Department of Chemistry and
Biochemistry, Montana State University, Bozeman, Montana 59717, United States
| | - Benjamin
R. Duffus
- Department of Chemistry and
Biochemistry, Montana State University, Bozeman, Montana 59717, United States
| | - Kaitlin S. Duschene
- Department of Chemistry and
Biochemistry, Montana State University, Bozeman, Montana 59717, United States
| | - Eric M. Shepard
- Department of Chemistry and
Biochemistry, Montana State University, Bozeman, Montana 59717, United States
| |
Collapse
|
31
|
Silver SC, Gardenghi DJ, Naik SG, Shepard EM, Huynh BH, Szilagyi RK, Broderick JB. Combined Mössbauer spectroscopic, multi-edge X-ray absorption spectroscopic, and density functional theoretical study of the radical SAM enzyme spore photoproduct lyase. J Biol Inorg Chem 2014; 19:465-83. [PMID: 24532333 PMCID: PMC4089880 DOI: 10.1007/s00775-014-1104-y] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/18/2013] [Accepted: 01/13/2014] [Indexed: 11/30/2022]
Abstract
Spore photoproduct lyase (SPL), a member of the radical S-adenosyl-L-methionine (SAM) superfamily, catalyzes the direct reversal of the spore photoproduct, a thymine dimer specific to bacterial spores, to two thymines. SPL requires SAM and a redox-active [4Fe-4S] cluster for catalysis. Mössbauer analysis of anaerobically purified SPL indicates the presence of a mixture of cluster states with the majority (40 %) as [2Fe-2S](2+) clusters and a smaller amount (15 %) as [4Fe-4S](2+) clusters. On reduction, the cluster content changes to primarily (60 %) [4Fe-4S](+). The speciation information from Mössbauer data allowed us to deconvolute iron and sulfur K-edge X-ray absorption spectra to uncover electronic (X-ray absorption near-edge structure, XANES) and geometric (extended X-ray absorption fine structure, EXAFS) structural features of the Fe-S clusters, and their interactions with SAM. The iron K-edge EXAFS data provide evidence for elongation of a [2Fe-2S] rhomb of the [4Fe-4S] cluster on binding SAM on the basis of an Fe···Fe scatterer at 3.0 Å. The XANES spectra of reduced SPL in the absence and presence of SAM overlay one another, indicating that SAM is not undergoing reductive cleavage. The X-ray absorption spectroscopy data for SPL samples and data for model complexes from the literature allowed the deconvolution of contributions from [2Fe-2S] and [4Fe-4S] clusters to the sulfur K-edge XANES spectra. The analysis of pre-edge features revealed electronic changes in the Fe-S clusters as a function of the presence of SAM. The spectroscopic findings were further corroborated by density functional theory calculations that provided insights into structural and electronic perturbations that can be correlated by considering the role of SAM as a catalyst or substrate.
Collapse
Affiliation(s)
| | | | | | | | - Boi Hanh Huynh
- Department of Physics, Emory University, Atlanta, Georgia 30322
| | - Robert K. Szilagyi
- NAI Astrobiology Biogeocatalysis Research Center, Department of Chemistry & Biochemistry, Montana State University, Bozeman, MT, 59718
| | - Joan B. Broderick
- NAI Astrobiology Biogeocatalysis Research Center, Department of Chemistry & Biochemistry, Montana State University, Bozeman, MT, 59718
| |
Collapse
|
32
|
Kneuttinger AC, Kashiwazaki G, Prill S, Heil K, Müller M, Carell T. Formation and Direct Repair of UV-induced Dimeric DNA Pyrimidine Lesions. Photochem Photobiol 2013; 90:1-14. [PMID: 24354557 DOI: 10.1111/php.12197] [Citation(s) in RCA: 48] [Impact Index Per Article: 4.4] [Reference Citation Analysis] [Abstract] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/06/2013] [Accepted: 10/17/2013] [Indexed: 12/11/2022]
Abstract
Direct repair of UV-induced DNA lesions represents an elegant method for many organisms to deal with these highly mutagenic and cytotoxic compounds. Although the participating proteins are structurally well investigated, the exact repair mechanism of the photolyase enzymes remains a vivid subject of current research. In this review, we summarize and highlight the recent contributions to this exciting field.
Collapse
Affiliation(s)
- Andrea Christa Kneuttinger
- Center for Integrated Protein Sciences at the Department of Chemistry, Ludwig-Maximilians Universität München, Munich, Germany
| | - Gengo Kashiwazaki
- Center for Integrated Protein Sciences at the Department of Chemistry, Ludwig-Maximilians Universität München, Munich, Germany
| | - Stefan Prill
- Center for Integrated Protein Sciences at the Department of Chemistry, Ludwig-Maximilians Universität München, Munich, Germany
| | - Korbinian Heil
- Center for Integrated Protein Sciences at the Department of Chemistry, Ludwig-Maximilians Universität München, Munich, Germany
| | - Markus Müller
- Center for Integrated Protein Sciences at the Department of Chemistry, Ludwig-Maximilians Universität München, Munich, Germany
| | - Thomas Carell
- Center for Integrated Protein Sciences at the Department of Chemistry, Ludwig-Maximilians Universität München, Munich, Germany
| |
Collapse
|
33
|
Biogenesis of [Fe–S] cluster in Firmicutes: an unexploited field of investigation. Antonie Van Leeuwenhoek 2013; 104:283-300. [DOI: 10.1007/s10482-013-9966-5] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/23/2013] [Accepted: 06/28/2013] [Indexed: 10/26/2022]
|
34
|
Yang L, Li L. The enzyme-mediated direct reversal of a dithymine photoproduct in germinating endospores. Int J Mol Sci 2013; 14:13137-53. [PMID: 23799365 PMCID: PMC3742179 DOI: 10.3390/ijms140713137] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/02/2013] [Revised: 06/04/2013] [Accepted: 06/07/2013] [Indexed: 11/16/2022] Open
Abstract
Spore photoproduct lyase (SPL) repairs a special thymine dimer, 5-thyminyl-5,6-dihydrothymine, which is commonly called spore photoproduct, or SP, in germinating endospores. SP is the exclusive DNA photo-damaging product found in endospores; its generation and swift repair by SPL are responsible for the spores’ extremely high UV resistance. Early in vivo studies suggested that SPL utilizes a direct reversal strategy to repair SP in the absence of light. Recently, it has been established that SPL belongs to the radical S-adenosylmethionine (SAM) superfamily. The enzymes in this superfamily utilize a tri-cysteine CXXXCXXC motif to bind a [4Fe-4S] cluster. The cluster provides an electron to the S-adenosylmethionine (SAM) to reductively cleave its C5′-S bond, generating a reactive 5′-deoxyadenosyl (5′-dA) radical. This 5′-dA radical abstracts the proR hydrogen atom from the C6 carbon of SP to initiate the repair process; the resulting SP radical subsequently fragments to generate a putative thymine methyl radical, which accepts a back-donated H atom to yield the repaired TpT. The H atom donor is suggested to be a conserved cysteine141 in B. subtilis SPL; the resulting thiyl radical likely interacts with a neighboring tyrosine99 before oxidizing the 5′-dA to 5′-dA radical and, subsequently, regenerating SAM. These findings suggest SPL to be the first enzyme in the large radical SAM superfamily (>44,000 members) to utilize a radical transfer pathway for catalysis; its study should shed light on the mechanistic understanding of the SAM regeneration process in other members of the superfamily.
Collapse
Affiliation(s)
- Linlin Yang
- Department of Chemistry and Chemical Biology, Indiana University-Purdue University Indianapolis (IUPUI), 402 N Blackford Street, Indianapolis, IN 46202, USA; E-Mail:
| | - Lei Li
- Department of Chemistry and Chemical Biology, Indiana University-Purdue University Indianapolis (IUPUI), 402 N Blackford Street, Indianapolis, IN 46202, USA; E-Mail:
- Department of Biochemistry and Molecular Biology, Indiana University School of Medicine (IUSM), 635 Barnhill Drive, Indianapolis, IN 46202, USA
- Author to whom correspondence should be addressed; E-Mail: ; Tel.: +1-317-278-2202; Fax: +1-317-274-4701
| |
Collapse
|
35
|
Kneuttinger AC, Heil K, Kashiwazaki G, Carell T. The radical SAM enzyme spore photoproduct lyase employs a tyrosyl radical for DNA repair. Chem Commun (Camb) 2013; 49:722-4. [PMID: 23228940 DOI: 10.1039/c2cc37735g] [Citation(s) in RCA: 16] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022]
Abstract
The spore photoproduct lyase is a radical SAM enzyme, which repairs 5-(α-thyminyl)-5,6-dihydrothymidine. Here we show that the enzyme establishes a complex radical transfer cascade and creates a cysteine and a tyrosyl radical dyade to establish repair. This allows the enzyme to solve topological and energetic problems associated with the radical based repair reaction.
Collapse
Affiliation(s)
- Andrea Christa Kneuttinger
- Center for Integrative Protein Science at the Department for Chemistry, Ludwig-Maximilians-Universität, Butenandtstr. 5-13, 81377 Munich, Germany
| | | | | | | |
Collapse
|
36
|
Lin G, Li L. Oxidation and reduction of the 5-(2'-deoxyuridinyl)methyl radical. Angew Chem Int Ed Engl 2013; 52:5594-8. [PMID: 23589226 PMCID: PMC3689432 DOI: 10.1002/anie.201209454] [Citation(s) in RCA: 23] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/27/2012] [Revised: 02/25/2013] [Indexed: 11/09/2022]
Abstract
Sleeping beauty: The 5-(2’-Deoxyuridinyl) methyl radical 1 is a key intermediate in the thymine oxidative reaction mediated by reactive oxygen species. Evidence is presented that 1 is prone to both oxidation and reduction reactions at the absence of O2. These results question the current paradigm and suggest that the redox chemistry of 1 , which has been largely overlooked in the past, may play a major role in determining the fate of 1 .
Collapse
Affiliation(s)
- Gengjie Lin
- Department of Chemistry and Chemical Biology, Indiana University-Purdue University Indianapolis (IUPUI), 402 N. Blackford St., Indianapolis, IN 46202 (USA)
| | - Lei Li
- Department of Chemistry and Chemical Biology, Indiana University-Purdue University Indianapolis (IUPUI), 402 N. Blackford St., Indianapolis, IN 46202 (USA)
| |
Collapse
|
37
|
Yang L, Nelson RS, Benjdia A, Lin G, Telser J, Stoll S, Schlichting I, Li L. A radical transfer pathway in spore photoproduct lyase. Biochemistry 2013; 52:3041-50. [PMID: 23607538 DOI: 10.1021/bi3016247] [Citation(s) in RCA: 31] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/06/2023]
Abstract
Spore photoproduct lyase (SPL) repairs a covalent UV-induced thymine dimer, spore photoproduct (SP), in germinating endospores and is responsible for the strong UV resistance of endospores. SPL is a radical S-adenosyl-l-methionine (SAM) enzyme, which uses a [4Fe-4S](+) cluster to reduce SAM, generating a catalytic 5'-deoxyadenosyl radical (5'-dA(•)). This in turn abstracts a H atom from SP, generating an SP radical that undergoes β scission to form a repaired 5'-thymine and a 3'-thymine allylic radical. Recent biochemical and structural data suggest that a conserved cysteine donates a H atom to the thymine radical, resulting in a putative thiyl radical. Here we present structural and biochemical data that suggest that two conserved tyrosines are also critical in enzyme catalysis. One [Y99(Bs) in Bacillus subtilis SPL] is downstream of the cysteine, suggesting that SPL uses a novel hydrogen atom transfer (HAT) pathway with a pair of cysteine and tyrosine residues to regenerate SAM. The other tyrosine [Y97(Bs)] has a structural role to facilitate SAM binding; it may also contribute to the SAM regeneration process by interacting with the putative (•)Y99(Bs) and/or 5'-dA(•) intermediates to lower the energy barrier for the second H abstraction step. Our results indicate that SPL is the first member of the radical SAM superfamily (comprising more than 44000 members) to bear a catalytically operating HAT chain.
Collapse
Affiliation(s)
- Linlin Yang
- Department of Chemistry and Chemical Biology, Indiana University-Purdue University Indianapolis, Indianapolis, IN 46202, USA
| | | | | | | | | | | | | | | |
Collapse
|
38
|
Lin G, Li L. Oxidation and Reduction of the 5-(2′-Deoxyuridinyl)methyl Radical. Angew Chem Int Ed Engl 2013. [DOI: 10.1002/ange.201209454] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/10/2022]
|
39
|
Abstract
5-(α-Thyminyl)-5,6-dihydrothymine, also called spore photoproduct or SP, is commonly found in the genomic DNA of UV-irradiated bacterial endospores. Despite the fact that SP was discovered nearly 50 years ago, its biochemical impact is still largely unclear due to the difficulty of preparing SP-containing oligonucleotide in high purity. Here, we report the first synthesis of the phosphoramidite derivative of dinucleotide SP TpT, which enables successful incorporation of SP TpT into oligodeoxyribonucleotides with high efficiency via standard solid-phase synthesis. This result provides the scientific community a reliable means to prepare SP-containing oligonucleotides, laying the foundation for future SP biochemical studies. Thermal denaturation studies of the SP-containing oligonucleotide found that SP destabilizes the duplex by 10-20 kJ/mol, suggesting that its presence in the spore-genomic DNA may alter the DNA local conformation.
Collapse
Affiliation(s)
- Yajun Jian
- Department of Chemistry and Chemical Biology, Indiana University-Purdue University Indianapolis (IUPUI), Indianapolis, Indiana, 46202
| | - Lei Li
- Department of Chemistry and Chemical Biology, Indiana University-Purdue University Indianapolis (IUPUI), Indianapolis, Indiana, 46202
- Department of Biochemistry and Molecular Biology, Indiana University School of Medicine (IUSM), 635 Barnhill Drive, Indianapolis, Indiana 46202
| |
Collapse
|
40
|
Benjdia A. DNA photolyases and SP lyase: structure and mechanism of light-dependent and independent DNA lyases. Curr Opin Struct Biol 2012; 22:711-20. [PMID: 23164663 DOI: 10.1016/j.sbi.2012.10.002] [Citation(s) in RCA: 24] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/09/2012] [Revised: 09/30/2012] [Accepted: 10/02/2012] [Indexed: 10/27/2022]
Abstract
Light is essential for many critical biological processes including vision, circadian rhythms, photosynthesis and DNA repair. DNA photolyases use light energy and a fully reduced flavin cofactor to repair the major UV-induced DNA damages, the cis-syn cyclobutane pyrimidine dimers (CPDs) and the pyrimidine-pyrimidone (6-4) photoproducts. Catalysis involves two photoreactions, the photoactivation which leads to the conversion of the flavin cofactor to its catalytic active form and the photorepair whose efficiency depends on a light-harvesting antenna chromophore. Very interestingly, an alternative and light-independent direct reversal mechanism to repair a distinct photolesion is found in bacterial spores, catalyzed by spore photoproduct lyase. This radical SAM enzyme uses an iron-sulfur cluster and S-adenosyl-l-methionine (SAM) to split a specific photoproduct, the so-called spore photoproduct (SP), back to two thymidine residues. The recently solved crystal structure of SP lyase provides new insights into this unique DNA repair mechanism and allows a detailed comparison with DNA photolyases. Similarities as well as divergences between DNA photolyases and SP lyase are highlighted in this review.
Collapse
Affiliation(s)
- Alhosna Benjdia
- Department of Biomolecular Mechanisms, Max-Planck Institute for Medical Research, Jahnstrasse 29, Heidelberg, Germany.
| |
Collapse
|
41
|
Hioe J, Zipse H. Hydrogen transfer in SAM-mediated enzymatic radical reactions. Chemistry 2012; 18:16463-72. [PMID: 23139189 DOI: 10.1002/chem.201202869] [Citation(s) in RCA: 24] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/10/2012] [Indexed: 11/11/2022]
Abstract
S-adenosylmethionine (SAM) plays an essential role in a variety of enzyme-mediated radical reactions. One-electron reduction of SAM is currently believed to generate the C5'-desoxyadenosyl radical, which subsequently abstracts a hydrogen atom from the actual substrate in a catalytic or a non-catalytic fashion. Using a combination of theoretical and experimental bond dissociation energy (BDE) data, the energetics of these radical processes have now been quantified. SAM-derived radicals are found to react with their respective substrates in an exothermic fashion in enzymes using SAM in a stoichiometric (non-catalytic) way. In contrast, the catalytic use of SAM appears to be linked to a sequence of moderately endothermic and exothermic reaction steps. The use of SAM in spore photoproduct lyase (SPL) appears to fit neither of these general categories and appears to constitute the first example of a SAM-initiated radical reaction propagated independently of the cofactor.
Collapse
Affiliation(s)
- Johnny Hioe
- Department of Chemistry, LMU München, Butenandtstrasse 5-13, 81377 München, Germany
| | | |
Collapse
|
42
|
Li L. Mechanistic studies of the radical SAM enzyme spore photoproduct lyase (SPL). BIOCHIMICA ET BIOPHYSICA ACTA 2012; 1824:1264-77. [PMID: 22197590 PMCID: PMC3314140 DOI: 10.1016/j.bbapap.2011.11.008] [Citation(s) in RCA: 12] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 08/29/2011] [Accepted: 11/28/2011] [Indexed: 02/06/2023]
Abstract
Spore photoproduct lyase (SPL) repairs a special thymine dimer 5-thyminyl-5,6-dihydrothymine, which is commonly called spore photoproduct or SP at the bacterial early germination phase. SP is the exclusive DNA photo-damage product in bacterial endospores; its generation and swift repair by SPL are responsible for the spores' extremely high UV resistance. The early in vivo studies suggested that SPL utilizes a direct reversal strategy to repair the SP in the absence of light. The research in the past decade further established SPL as a radical SAM enzyme, which utilizes a tri-cysteine CXXXCXXC motif to harbor a [4Fe-4S] cluster. At the 1+ oxidation state, the cluster provides an electron to the S-adenosylmethionine (SAM), which binds to the cluster in a bidentate manner as the fourth and fifth ligands, to reductively cleave the CS bond associated with the sulfonium ion in SAM, generating a reactive 5'-deoxyadenosyl (5'-dA) radical. This 5'-dA radical abstracts the proR hydrogen atom from the C6 carbon of SP to initiate the repair process; the resulting SP radical subsequently fragments to generate a putative thymine methyl radical, which accepts a back-donated H atom to yield the repaired TpT. SAM is suggested to be regenerated at the end of each catalytic cycle; and only a catalytic amount of SAM is needed in the SPL reaction. The H atom source for the back donation step is suggested to be a cysteine residue (C141 in Bacillus subtilis SPL), and the H-atom transfer reaction leaves a thiyl radical behind on the protein. This thiyl radical thus must participate in the SAM regeneration process; however how the thiyl radical abstracts an H atom from the 5'-dA to regenerate SAM is unknown. This paper reviews and discusses the history and the latest progress in the mechanistic elucidation of SPL. Despite some recent breakthroughs, more questions are raised in the mechanistic understanding of this intriguing DNA repair enzyme. This article is part of a Special Issue entitled: Radical SAM enzymes and Radical Enzymology.
Collapse
Affiliation(s)
- Lei Li
- Department of Chemistry, Indiana University-Purdue University Indianapolis (IUPUI), 402 N Blackford Street, Indianapolis, IN 46202, USA.
| |
Collapse
|
43
|
Yang L, Lin G, Nelson RS, Jian Y, Telser J, Li L. Mechanistic studies of the spore photoproduct lyase via a single cysteine mutation. Biochemistry 2012; 51:7173-88. [PMID: 22906093 PMCID: PMC3448869 DOI: 10.1021/bi3010945] [Citation(s) in RCA: 29] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/31/2022]
Abstract
5-Thyminyl-5,6-dihydrothymine (also called spore photoproduct or SP) is the exclusive DNA photodamage product in bacterial endospores. It is repaired by a radical SAM (S-adenosylmethionine) enzyme, the spore photoproduct lyase (SPL), at the bacterial early germination phase. Our previous studies proved that SPL utilizes the 5'-dA• generated by the SAM cleavage reaction to abstract the H(6proR) atom to initiate the SP repair process. The resulting thymine allylic radical was suggested to take an H atom from an unknown protein source, most likely cysteine 141. Here we show that C141 can be readily alkylated in the native SPL by an iodoacetamide treatment, suggesting that it is accessible to the TpT radical. SP repair by the SPL C141A mutant yields TpTSO(2)(-) and TpT simultaneously from the very beginning of the reaction; no lag phase is observed for TpTSO(2)(-) formation. Should any other protein residue serve as the H donor, its presence would result in TpT being the major product at least for the first enzyme turnover. These observations provide strong evidence to support C141 as the direct H atom donor. Moreover, because of the lack of this intrinsic H donor, the C141A mutant produces TpT via an unprecedented thymine cation radical reduction (proton-coupled electron transfer) process, contrasting to the H atom transfer mechanism in the wild-type (WT) SPL reaction. The C141A mutant repairs SP at a rate that is ~3-fold slower than that of the WT enzyme. Formation of TpTSO(2)(-) and TpT exhibits a V(max) deuterium kinetic isotope effect (KIE) of 1.7 ± 0.2, which is smaller than the (D)V(max) KIE of 2.8 ± 0.3 determined for the WT SPL reaction. These findings suggest that removing the intrinsic H atom donor disturbs the rate-limiting process during enzyme catalysis. As expected, the prereduced C141A mutant supports only ~0.4 turnover, which is in sharp contrast to the >5 turnovers exhibited by the WT SPL reaction, suggesting that the enzyme catalytic cycle (SAM regeneration) is disrupted by this single mutation.
Collapse
Affiliation(s)
- Linlin Yang
- Department of Chemistry and Chemical Biology, Indiana University-Purdue University Indianapolis (IUPUI), 402 N Blackford Street, Indianapolis, Indiana, 46202
| | - Gengjie Lin
- Department of Chemistry and Chemical Biology, Indiana University-Purdue University Indianapolis (IUPUI), 402 N Blackford Street, Indianapolis, Indiana, 46202
| | - Renae S. Nelson
- Department of Chemistry and Chemical Biology, Indiana University-Purdue University Indianapolis (IUPUI), 402 N Blackford Street, Indianapolis, Indiana, 46202
| | - Yajun Jian
- Department of Chemistry and Chemical Biology, Indiana University-Purdue University Indianapolis (IUPUI), 402 N Blackford Street, Indianapolis, Indiana, 46202
| | - Joshua Telser
- Department of Biological, Chemical, and Physical Sciences, Roosevelt University, Chicago, Illinois 60605
| | - Lei Li
- Department of Chemistry and Chemical Biology, Indiana University-Purdue University Indianapolis (IUPUI), 402 N Blackford Street, Indianapolis, Indiana, 46202
- Department of Biochemistry and Molecular Biology, Indiana University School of Medicine (IUSM), 635 Barnhill Drive, Indianapolis, Indiana 46202
| |
Collapse
|
44
|
Benjdia A, Heil K, Barends TRM, Carell T, Schlichting I. Structural insights into recognition and repair of UV-DNA damage by Spore Photoproduct Lyase, a radical SAM enzyme. Nucleic Acids Res 2012; 40:9308-18. [PMID: 22761404 PMCID: PMC3467042 DOI: 10.1093/nar/gks603] [Citation(s) in RCA: 67] [Impact Index Per Article: 5.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/02/2022] Open
Abstract
Bacterial spores possess an enormous resistance to ultraviolet (UV) radiation. This is largely due to a unique DNA repair enzyme, Spore Photoproduct Lyase (SP lyase) that repairs a specific UV-induced DNA lesion, the spore photoproduct (SP), through an unprecedented radical-based mechanism. Unlike DNA photolyases, SP lyase belongs to the emerging superfamily of radical S-adenosyl-l-methionine (SAM) enzymes and uses a [4Fe–4S]1+ cluster and SAM to initiate the repair reaction. We report here the first crystal structure of this enigmatic enzyme in complex with its [4Fe–4S] cluster and its SAM cofactor, in the absence and presence of a DNA lesion, the dinucleoside SP. The high resolution structures provide fundamental insights into the active site, the DNA lesion recognition and binding which involve a β-hairpin structure. We show that SAM and a conserved cysteine residue are perfectly positioned in the active site for hydrogen atom abstraction from the dihydrothymine residue of the lesion and donation to the α-thyminyl radical moiety, respectively. Based on structural and biochemical characterizations of mutant proteins, we substantiate the role of this cysteine in the enzymatic mechanism. Our structure reveals how SP lyase combines specific features of radical SAM and DNA repair enzymes to enable a complex radical-based repair reaction to take place.
Collapse
Affiliation(s)
- Alhosna Benjdia
- Department of Biomolecular Mechanisms, Max-Planck Institute for Medical Research, Jahnstrasse 29, 69120 Heidelberg, Germany.
| | | | | | | | | |
Collapse
|
45
|
Lin G, Chen CH, Pink M, Pu J, Li L. Chemical synthesis, crystal structure and enzymatic evaluation of a dinucleotide spore photoproduct analogue containing a formacetal linker. Chemistry 2011; 17:9658-68. [PMID: 21780208 PMCID: PMC3180863 DOI: 10.1002/chem.201101821] [Citation(s) in RCA: 19] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/14/2011] [Indexed: 11/11/2022]
Abstract
Spore photoproduct (SP) is the exclusive DNA photodamage product found in bacterial endospores. Its photoformation and repair by a metalloenzyme spore photoproduct lyase (SPL) composes the unique SP biochemistry. Despite the fact that the SP was discovered almost 50 years ago, its crystal structure is still unknown and the lack of structural information greatly hinders the study of SP biochemistry. Employing a formacetal linker and organic synthesis, we successfully prepared a dinucleotide SP isostere 5R-CH(2) SP, which contains a neutral CH(2) moiety between the two thymine residues instead of a phosphate. The neutral linker dramatically facilitates the crystallization process, allowing us to obtain the crystal structure for this intriguing thymine dimer half a century after its discovery. Further ROESY spectroscopic, DFT computational, and enzymatic studies of this 5R-CH(2) SP compound prove that it possesses similar properties with the 5R-SP species, suggesting that the revealed structure truly reflects that of SP generated in Nature.
Collapse
Affiliation(s)
- Gengjie Lin
- Department of Chemistry and Chemical Biology, Indiana University, Purdue University Indianapolis (IUPUI), 402 N. Blackford St., Indianapolis, IN 46202 (USA)
| | - Chun-Hsing Chen
- Indiana University Molecular Structure Center, Chemistry, A421, Indiana University, 800 E. Kirkwood Avenue, Bloomington, IN 47405 (USA)
| | - Maren Pink
- Indiana University Molecular Structure Center, Chemistry, A421, Indiana University, 800 E. Kirkwood Avenue, Bloomington, IN 47405 (USA)
| | - Jingzhi Pu
- Department of Chemistry and Chemical Biology, Indiana University, Purdue University Indianapolis (IUPUI), 402 N. Blackford St., Indianapolis, IN 46202 (USA)
| | - Lei Li
- Department of Chemistry and Chemical Biology, Indiana University, Purdue University Indianapolis (IUPUI), 402 N. Blackford St., Indianapolis, IN 46202 (USA)
- Department of Biochemistry and Molecular Biology, Indiana University School of Medicine, 635 Barnhill Drive, Indianapolis, IN 46202 (USA)
| |
Collapse
|
46
|
Heil K, Kneuttinger AC, Schneider S, Lischke U, Carell T. Crystal structures and repair studies reveal the identity and the base-pairing properties of the UV-induced spore photoproduct DNA lesion. Chemistry 2011; 17:9651-7. [PMID: 21780197 DOI: 10.1002/chem.201100177] [Citation(s) in RCA: 27] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/18/2011] [Revised: 05/05/2011] [Indexed: 11/11/2022]
Abstract
UV light is one of the major causes of DNA damage. In spore DNA, due to an unusual packing of the genetic material, a special spore photoproduct lesion (SP lesion) is formed, which is repaired by the enzyme spore photoproduct lyase (Spl), a radical S-adenosylmethionine (SAM) enzyme. We report here the synthesis and DNA incorporation of a DNA SP lesion analogue lacking the phosphodiester backbone. The oligonucleotides were used for repair studies and they were cocrystallized with a polymerase enzyme as a template to clarify the configuration of the SP lesion and to provide information about the base-pairing properties of the lesion. The structural analysis together with repair studies allowed us to clarify the identity of the preferentially repaired lesion diastereoisomer.
Collapse
Affiliation(s)
- Korbinian Heil
- Center for Integrated Protein Science (CiPSM) at the Department of Chemistry, Ludwig-Maximilians-University, Munich, Germany
| | | | | | | | | |
Collapse
|
47
|
Yang L, Lin G, Liu D, Dria KJ, Telser J, Li L. Probing the reaction mechanism of spore photoproduct lyase (SPL) via diastereoselectively labeled dinucleotide SP TpT substrates. J Am Chem Soc 2011; 133:10434-47. [PMID: 21671623 DOI: 10.1021/ja110196d] [Citation(s) in RCA: 33] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
Abstract
5-Thyminyl-5,6-dihydrothymine (commonly called spore photoproduct or SP) is the exclusive DNA photodamage product in bacterial endospores. It is generated in the bacterial sporulation phase and repaired by a radical SAM enzyme, spore photoproduct lyase (SPL), at the early germination phase. SPL utilizes a special [4Fe-4S] cluster to reductively cleave S-adenosylmethionine (SAM) to generate a reactive 5'-dA radical. The 5'-dA radical is proposed to abstract one of the two H-atoms at the C6 carbon of SP to initiate the repair process. Via organic synthesis and DNA photochemistry, we selectively labeled the 6-H(proS) or 6-H(proR) position with a deuterium in a dinucleotide SP TpT substrate. Monitoring the deuterium migration in enzyme catalysis (employing Bacillus subtilis SPL) revealed that it is the 6-H(proR) atom of SP that is abstracted by the 5'-dA radical. Surprisingly, the abstracted deuterium was not returned to the resulting TpT after enzymatic catalysis; an H-atom from the aqueous buffer was incorporated into TpT instead. This result questions the currently hypothesized SPL mechanism which excludes the involvement of protein residue(s) in SPL reaction, suggesting that some protein residue(s), which is capable of exchanging a proton with the aqueous buffer, is involved in the enzyme catalysis. Moreover, evidence has been obtained for a possible SAM regeneration after each catalytic cycle; however, such a regeneration process is more complex than currently thought, with one or even more protein residues involved as well. These observations have enabled us to propose a modified reaction mechanism for this intriguing DNA repair enzyme.
Collapse
Affiliation(s)
- Linlin Yang
- Department of Chemistry and Chemical Biology, Indiana University-Purdue University Indianapolis (IUPUI), 402 N Blackford Street, Indianapolis, Indiana 46202, USA
| | | | | | | | | | | |
Collapse
|
48
|
Lin G, Li L. Elucidation of spore-photoproduct formation by isotope labeling. Angew Chem Int Ed Engl 2011; 49:9926-9. [PMID: 21104967 DOI: 10.1002/anie.201005228] [Citation(s) in RCA: 34] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/07/2022]
Affiliation(s)
- Gengjie Lin
- Department of Chemistry and Chemical Biology, Indiana University-Purdue University Indianapolis, 402 North Blackford Street, Indianapolis, IN 46202, USA
| | | |
Collapse
|
49
|
|
50
|
Heil K, Pearson D, Carell T. Chemical investigation of light induced DNA bipyrimidine damage and repair. Chem Soc Rev 2010; 40:4271-8. [PMID: 21076781 DOI: 10.1039/c000407n] [Citation(s) in RCA: 44] [Impact Index Per Article: 3.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022]
Abstract
In all organisms, genetic information is stored in DNA and RNA. Both of these macromolecules are damaged by many exogenous and endogenous events, with UV irradiation being one of the major sources of damage. The major photolesions formed are the cyclobutane pyrimidine dimers (CPD), pyrimidine-pyrimidone-(6-4)-photoproducts, Dewar valence isomers and, for dehydrated spore DNA, 5-(α-thyminyl)-5,6-dihydrothymine (SP). In order to be able to investigate how nature's repair and tolerance mechanisms protect the integrity of genetic information, oligonucleotides containing sequence and site-specific UV lesions are essential. This tutorial review provides an overview of synthetic procedures by which these oligonucleotides can be generated, either through phosphoramidite chemistry or direct irradiation of DNA. Moreover, a brief summary on their usage in analysing repair and tolerance processes as well as their biological effects is provided.
Collapse
Affiliation(s)
- Korbinian Heil
- Center for Integrative Protein Science CiPSM at the Department of Chemistry and Biochemistry, Ludwig-Maximilians University Munich, Butenandtstr. 5-13, D-81377 Munich, Germany
| | | | | |
Collapse
|