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Natarajan L, De Sciscio ML, Nardi AN, Sekhar A, Del Giudice A, D’Abramo M, Naganathan AN. A finely balanced order-disorder equilibrium sculpts the folding-binding landscape of an antibiotic sequestering protein. Proc Natl Acad Sci U S A 2024; 121:e2318855121. [PMID: 38709926 PMCID: PMC11098121 DOI: 10.1073/pnas.2318855121] [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: 10/27/2023] [Accepted: 03/24/2024] [Indexed: 05/08/2024] Open
Abstract
TipA, a MerR family transcription factor from Streptomyces lividans, promotes antibiotic resistance by sequestering broad-spectrum thiopeptide-based antibiotics, thus counteracting their inhibitory effect on ribosomes. TipAS, a minimal binding motif which is expressed as an isoform of TipA, harbors a partially disordered N-terminal subdomain that folds upon binding multiple antibiotics. The extent and nature of the underlying molecular heterogeneity in TipAS that shapes its promiscuous folding-function landscape is an open question and is critical for understanding antibiotic-sequestration mechanisms. Here, combining equilibrium and time-resolved experiments, statistical modeling, and simulations, we show that the TipAS native ensemble exhibits a pre-equilibrium between binding-incompetent and binding-competent substates, with the fully folded state appearing only as an excited state under physiological conditions. The binding-competent state characterized by a partially structured N-terminal subdomain loses structure progressively in the physiological range of temperatures, swells on temperature increase, and displays slow conformational exchange across multiple conformations. Binding to the bactericidal antibiotic thiostrepton follows a combination of induced-fit and conformational-selection-like mechanisms, via partial binding and concomitant stabilization of the binding-competent substate. These ensemble features are evolutionarily conserved across orthologs from select bacteria that infect humans, underscoring the functional role of partial disorder in the native ensemble of antibiotic-sequestering proteins belonging to the MerR family.
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Affiliation(s)
- Lawanya Natarajan
- Department of Biotechnology, Bhupat and Jyoti Mehta School of Biosciences, Indian Institute of Technology Madras, Chennai600036, India
| | | | | | - Ashok Sekhar
- Molecular Biophysics Unit, Indian Institute of Science Bangalore, Bengaluru560 012, India
| | | | - Marco D’Abramo
- Department of Chemistry, Sapienza University of Rome, Rome00185, Italy
| | - Athi N. Naganathan
- Department of Biotechnology, Bhupat and Jyoti Mehta School of Biosciences, Indian Institute of Technology Madras, Chennai600036, India
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2
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Ji CH, Je HW, Kim H, Kang HS. Promoter engineering of natural product biosynthetic gene clusters in actinomycetes: concepts and applications. Nat Prod Rep 2024; 41:672-699. [PMID: 38259139 DOI: 10.1039/d3np00049d] [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: 01/24/2024]
Abstract
Covering 2011 to 2022Low titers of natural products in laboratory culture or fermentation conditions have been one of the challenging issues in natural products research. Many natural product biosynthetic gene clusters (BGCs) are also transcriptionally silent in laboratory culture conditions, making it challenging to characterize the structures and activities of their metabolites. Promoter engineering offers a potential solution to this problem by providing tools for transcriptional activation or optimization of biosynthetic genes. In this review, we summarize the 10 years of progress in promoter engineering approaches in natural products research focusing on the most metabolically talented group of bacteria actinomycetes.
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Affiliation(s)
- Chang-Hun Ji
- Department of Biomedical Science and Engineering, Konkuk University, Seoul 05029, Korea.
| | - Hyun-Woo Je
- Department of Biomedical Science and Engineering, Konkuk University, Seoul 05029, Korea.
| | - Hiyoung Kim
- Department of Biomedical Science and Engineering, Konkuk University, Seoul 05029, Korea.
| | - Hahk-Soo Kang
- Department of Biomedical Science and Engineering, Konkuk University, Seoul 05029, Korea.
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3
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Bailly C. The bacterial thiopeptide thiostrepton. An update of its mode of action, pharmacological properties and applications. Eur J Pharmacol 2022; 914:174661. [PMID: 34863996 DOI: 10.1016/j.ejphar.2021.174661] [Citation(s) in RCA: 4] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/15/2021] [Accepted: 11/29/2021] [Indexed: 12/20/2022]
Abstract
The bacterial thiopeptide thiostrepton (TS) is used as a veterinary medicine to treat bacterial infections. TS is a protein translation inhibitor, essentially active against Gram-positive bacteria and some Gram-negative bacteria. In procaryotes, TS abrogates binding of GTPase elongation factors to the 70S ribosome, by altering the structure of rRNA-L11 protein complexes. TS exerts also antimalarial effects by disrupting protein synthesis in the apicoplast genome of Plasmodium falciparum. Interestingly, the drug targets both the infectious pathogen (bacteria or parasite) and host cell, by inducing endoplasmic reticulum stress-mediated autophagy which contributes to enhance the host cell defense. In addition, TS has been characterized as a potent chemical inhibitor of the oncogenic transcription factor FoxM1, frequently overexpressed in cancers or other diseases. The capacity of TS to crosslink FoxM1, and a few other proteins such as peroxiredoxin 3 (PRX3) and the 19S proteasome, contributes to the anticancer effects of the thiopeptide. The anticancer activities of TS evidenced using diverse tumor cell lines, in vivo models and drug combinations are reviewed here, together with the implicated targets and mechanisms. The difficulty to formulate TS is a drag on the pharmaceutical development of the natural product. However, the design of hemisynthetic analogues and the use of micellar drug delivery systems should facilitate a broader utilization of the compound in human and veterinary medicines. This review shed light on the many pharmacological properties of TS, with the objective to promote its use as a pharmacological tool and medicinal product.
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Affiliation(s)
- Christian Bailly
- OncoWitan, Scientific Consulting Office, Lille, Wasquehal, 59290, France.
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Fang C, Zhang Y. Bacterial MerR family transcription regulators: activationby distortion. Acta Biochim Biophys Sin (Shanghai) 2021; 54:25-36. [PMID: 35130613 PMCID: PMC9909328 DOI: 10.3724/abbs.2021003] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/25/2022] Open
Abstract
Transcription factors (TFs) modulate gene expression by regulating the accessibility of promoter DNA to RNA polymerases (RNAPs) in bacteria. The MerR family TFs are a large class of bacterial proteins unique in their physiological functions and molecular action: they function as transcription repressors under normal circumstances, but rapidly transform to transcription activators under various cellular triggers, including oxidative stress, imbalance of cellular metal ions, and antibiotic challenge. The promoters regulated by MerR TFs typically contain an abnormal long spacer between the -35 and -10 elements, where MerR TFs bind and regulate transcription activity through unique mechanisms. In this review, we summarize the function, ligand reception, DNA recognition, and molecular mechanism of transcription regulation of MerR-family TFs.
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Affiliation(s)
- Chengli Fang
- Key Laboratory of Synthetic BiologyCAS Center for Excellence in Molecular Plant SciencesShanghai Institute of Plant Physiology and EcologyChinese Academy of SciencesShanghai200032China
| | - Yu Zhang
- Key Laboratory of Synthetic BiologyCAS Center for Excellence in Molecular Plant SciencesShanghai Institute of Plant Physiology and EcologyChinese Academy of SciencesShanghai200032China
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Chan DCK, Burrows LL. Thiopeptides: antibiotics with unique chemical structures and diverse biological activities. J Antibiot (Tokyo) 2020; 74:161-175. [PMID: 33349675 DOI: 10.1038/s41429-020-00387-x] [Citation(s) in RCA: 27] [Impact Index Per Article: 6.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/21/2020] [Revised: 10/05/2020] [Accepted: 10/21/2020] [Indexed: 12/13/2022]
Abstract
Thiopeptides are a class of natural product antibiotics with diverse structures and functions. Their complex structures and biosynthesis have intrigued researchers since their discovery in 1948, but not a single thiopeptide has been approved for human use. This is mainly due to their poor solubility, challenging synthesis, and low bioavailability. This review summarizes the current research on the biosynthesis and biological activity of thiopeptide antibiotics since 2015. The focus of research since 2015 has been on uncovering biosynthetic routes, developing methods for total synthesis, and understanding the biological activity of thiopeptides. Overall, there is still much to learn about this family of molecules.
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Affiliation(s)
- Derek C K Chan
- Department of Biochemistry and Biomedical Sciences, McMaster University, Hamilton, ON, Canada.,Michael G. DeGroote Institute for Infectious Diseases Research, McMaster University, Hamilton, ON, Canada
| | - Lori L Burrows
- Department of Biochemistry and Biomedical Sciences, McMaster University, Hamilton, ON, Canada. .,Michael G. DeGroote Institute for Infectious Diseases Research, McMaster University, Hamilton, ON, Canada.
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Jiang X, Zhang L, Teng M, Li X. Antibiotic binding releases autoinhibition of the TipA multidrug-resistance transcriptional regulator. J Biol Chem 2020; 295:17865-17876. [PMID: 33454020 PMCID: PMC7762955 DOI: 10.1074/jbc.ra120.016295] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/06/2020] [Revised: 10/21/2020] [Indexed: 11/29/2022] Open
Abstract
Investigations of bacterial resistance strategies can aid in the development of new antimicrobial drugs as a countermeasure to the increasing worldwide prevalence of bacterial antibiotic resistance. One such strategy involves the TipA class of transcription factors, which constitute minimal autoregulated multidrug resistance (MDR) systems against diverse antibiotics. However, we have insufficient information regarding how antibiotic binding induces transcriptional activation to design molecules that could interfere with this process. To learn more, we determined the crystal structure of SkgA from Caulobacter crescentus as a representative TipA protein. We identified an unexpected spatial orientation and location of the antibiotic-binding TipAS effector domain in the apo state. We observed that the α6–α7 region of the TipAS domain, which is canonically responsible for forming the lid of antibiotic-binding cleft to tightly enclose the bound antibiotic, is involved in the dimeric interface and stabilized via interaction with the DNA-binding domain in the apo state. Further structural and biochemical analyses demonstrated that the unliganded TipAS domain sterically hinders promoter DNA binding but undergoes a remarkable conformational shift upon antibiotic binding to release this autoinhibition via a switch of its α6–α7 region. Hence, the promoters for MDR genes including tipA and RNA polymerases become available for transcription, enabling efficient antibiotic resistance. These insights into the molecular mechanism of activation of TipA proteins advance our understanding of TipA proteins, as well as bacterial MDR systems, and may provide important clues to block bacterial resistance.
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Affiliation(s)
- Xuguang Jiang
- Hefei National Laboratory for Physical Sciences at Microscale, School of Life Sciences, National Synchrotron Radiation Laboratory, University of Science and Technology of China, Hefei, Anhui, China; Department of Cell Biology and Anatomy, Graduate School of Medicine, University of Tokyo, Tokyo, Japan.
| | - Linjuan Zhang
- Hefei National Laboratory for Physical Sciences at Microscale, School of Life Sciences, National Synchrotron Radiation Laboratory, University of Science and Technology of China, Hefei, Anhui, China
| | - Maikun Teng
- Hefei National Laboratory for Physical Sciences at Microscale, School of Life Sciences, National Synchrotron Radiation Laboratory, University of Science and Technology of China, Hefei, Anhui, China
| | - Xu Li
- Hefei National Laboratory for Physical Sciences at Microscale, School of Life Sciences, National Synchrotron Radiation Laboratory, University of Science and Technology of China, Hefei, Anhui, China.
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Burkhart BJ, Schwalen CJ, Mann G, Naismith JH, Mitchell DA. YcaO-Dependent Posttranslational Amide Activation: Biosynthesis, Structure, and Function. Chem Rev 2017; 117:5389-5456. [PMID: 28256131 DOI: 10.1021/acs.chemrev.6b00623] [Citation(s) in RCA: 138] [Impact Index Per Article: 19.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/18/2023]
Abstract
With advances in sequencing technology, uncharacterized proteins and domains of unknown function (DUFs) are rapidly accumulating in sequence databases and offer an opportunity to discover new protein chemistry and reaction mechanisms. The focus of this review, the formerly enigmatic YcaO superfamily (DUF181), has been found to catalyze a unique phosphorylation of a ribosomal peptide backbone amide upon attack by different nucleophiles. Established nucleophiles are the side chains of Cys, Ser, and Thr which gives rise to azoline/azole biosynthesis in ribosomally synthesized and posttranslationally modified peptide (RiPP) natural products. However, much remains unknown about the potential for YcaO proteins to collaborate with other nucleophiles. Recent work suggests potential in forming thioamides, macroamidines, and possibly additional post-translational modifications. This review covers all knowledge through mid-2016 regarding the biosynthetic gene clusters (BGCs), natural products, functions, mechanisms, and applications of YcaO proteins and outlines likely future research directions for this protein superfamily.
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Affiliation(s)
| | | | - Greg Mann
- Biomedical Science Research Complex, University of St Andrews , BSRC North Haugh, St Andrews KY16 9ST, United Kingdom
| | - James H Naismith
- Biomedical Science Research Complex, University of St Andrews , BSRC North Haugh, St Andrews KY16 9ST, United Kingdom.,State Key Laboratory of Biotherapy, Sichuan University , Sichuan, China
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Myers CL, Kuiper EG, Grant PC, Hernandez J, Conn GL, Honek JF. Functional roles in S-adenosyl-L-methionine binding and catalysis for active site residues of the thiostrepton resistance methyltransferase. FEBS Lett 2015; 589:3263-70. [PMID: 26450779 DOI: 10.1016/j.febslet.2015.09.028] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/14/2015] [Revised: 09/28/2015] [Accepted: 09/28/2015] [Indexed: 11/17/2022]
Abstract
Resistance to the antibiotic thiostrepton, in producing Streptomycetes, is conferred by the S-adenosyl-L-methionine (SAM)-dependent SPOUT methyltransferase Tsr. For this and related enzymes, the roles of active site amino acids have been inadequately described. Herein, we have probed SAM interactions in the Tsr active site by investigating the catalytic activity and the thermodynamics of SAM binding by site-directed Tsr mutants. Two arginine residues were demonstrated to be critical for binding, one of which appears to participate in the catalytic reaction. Additionally, evidence consistent with the involvement of an asparagine in the structural organization of the SAM binding site is presented.
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Affiliation(s)
- Cullen L Myers
- Department of Chemistry, University of Waterloo, Waterloo, Ontario N2L 3G1, Canada
| | - Emily G Kuiper
- Department of Biochemistry, Emory University School of Medicine, Atlanta, GA 30322, USA
| | - Pei C Grant
- Department of Chemistry, University of Waterloo, Waterloo, Ontario N2L 3G1, Canada
| | - Jennifer Hernandez
- Department of Biochemistry, Emory University School of Medicine, Atlanta, GA 30322, USA
| | - Graeme L Conn
- Department of Biochemistry, Emory University School of Medicine, Atlanta, GA 30322, USA
| | - John F Honek
- Department of Chemistry, University of Waterloo, Waterloo, Ontario N2L 3G1, Canada.
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Abstract
Carbon–sulfur biological chemistry encompasses a fascinating area of biochemistry and medicinal chemistry and includes the roles that methionine and S-adenosyl-l-methionine play in cells as well as the chemistry of intracellular thiols such as glutathione. This article, based on the 2014 Bernard Belleau Award lecture, provides an overview of some of the key investigations that were undertaken in this area from a bioorganic perspective. The research has ameliorated our fundamental knowledge of several of the enzymes utilizing these sulfur-containing molecules, has led to the development of several novel 19F biophysical probes, and has explored some of the medicinal chemistry associated with these processes.
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Affiliation(s)
- John F. Honek
- Department of Chemistry, University of Waterloo, 200 University Avenue West, Waterloo, ON N2L 3G1, Canada
- Department of Chemistry, University of Waterloo, 200 University Avenue West, Waterloo, ON N2L 3G1, Canada
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