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Fukui K, Fujii Y, Yano T. Identification of a Catalytic Lysine Residue Conserved Among GHKL ATPases: MutL, GyrB, and MORC. J Mol Biol 2024; 436:168575. [PMID: 38641238 DOI: 10.1016/j.jmb.2024.168575] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/05/2024] [Revised: 04/08/2024] [Accepted: 04/12/2024] [Indexed: 04/21/2024]
Abstract
DNA mismatch repair endonuclease MutL is a member of GHKL ATPase superfamily. Mutations of MutL homologs are causative of a hereditary cancer, Lynch syndrome. We characterized MutL homologs from human and a hyperthermophile, Aquifex aeolicus, (aqMutL) to reveal the catalytic mechanism for the ATPase activity. Although involvement of a basic residue had not been conceived in the catalytic mechanism, analysis of the pH dependence of the aqMutL ATPase activity revealed that the reaction is catalyzed by a residue with an alkaline pKa. Analyses of mutant aqMutLs showed that Lys79 is the catalytic residue, and the corresponding residues were confirmed to be critical for activities of human MutL homologs, on the basis of which a catalytic mechanism for MutL ATPase is proposed. These and other results described here would contribute to evaluating the pathogenicity of Lynch syndrome-associated missense mutations. Furthermore, it was confirmed that the catalytic lysine residue is conserved among DNA gyrases and microrchidia ATPases, other members of GHKL ATPases, indicating that the catalytic mechanism proposed here is applicable to these members of the superfamily.
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Affiliation(s)
- Kenji Fukui
- Department of Biochemistry, Faculty of Medicine, Osaka Medical and Pharmaceutical University, Takatsuki, Osaka, Japan.
| | - Yuki Fujii
- Graduate School of Science, Osaka City University, Sumiyoshi-ku, Osaka, Japan
| | - Takato Yano
- Department of Biochemistry, Faculty of Medicine, Osaka Medical and Pharmaceutical University, Takatsuki, Osaka, Japan.
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2
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Yu L, Xu X, Chua WZ, Feng H, Ser Z, Shao K, Shi J, Wang Y, Li Z, Sobota RM, Sham LT, Luo M. Structural basis of peptide secretion for Quorum sensing by ComA. Nat Commun 2023; 14:7178. [PMID: 37935699 PMCID: PMC10630487 DOI: 10.1038/s41467-023-42852-9] [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: 04/12/2023] [Accepted: 10/23/2023] [Indexed: 11/09/2023] Open
Abstract
Quorum sensing (QS) is a crucial regulatory mechanism controlling bacterial signalling and holds promise for novel therapies against antimicrobial resistance. In Gram-positive bacteria, such as Streptococcus pneumoniae, ComA is a conserved efflux pump responsible for the maturation and secretion of peptide signals, including the competence-stimulating peptide (CSP), yet its structure and function remain unclear. Here, we functionally characterize ComA as an ABC transporter with high ATP affinity and determined its cryo-EM structures in the presence or absence of CSP or nucleotides. Our findings reveal a network of strong electrostatic interactions unique to ComA at the intracellular gate, a putative binding pocket for two CSP molecules, and negatively charged residues facilitating CSP translocation. Mutations of these residues affect ComA's peptidase activity in-vitro and prevent CSP export in-vivo. We demonstrate that ATP-Mg2+ triggers the outward-facing conformation of ComA for CSP release, rather than ATP alone. Our study provides molecular insights into the QS signal peptide secretion, highlighting potential targets for QS-targeting drugs.
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Affiliation(s)
- Lin Yu
- Department of Biological Sciences, Faculty of Science, National University of Singapore, Singapore, 117543, Singapore
- Institute of Translational Medicine, Medical College, Yangzhou University, Yangzhou, 225001, Jiangsu, China
| | - Xin Xu
- Department of Biological Sciences, Faculty of Science, National University of Singapore, Singapore, 117543, Singapore
| | - Wan-Zhen Chua
- Infectious Diseases Translational Research Programme and Department of Microbiology and Immunology, Yong Loo Lin School of Medicine, National University of Singapore, Singapore, 117545, Singapore
| | - Hao Feng
- Department of Biological Sciences, Faculty of Science, National University of Singapore, Singapore, 117543, Singapore
| | - Zheng Ser
- Functional Proteomics Laboratory, SingMass National Laboratory, Institute of Molecular and Cell Biology, Agency for Science, Technology and Research (A*STAR), Singapore, 138673, Singapore
| | - Kai Shao
- Department of Biological Sciences, Faculty of Science, National University of Singapore, Singapore, 117543, Singapore
| | - Jian Shi
- Department of Biological Sciences, Faculty of Science, National University of Singapore, Singapore, 117543, Singapore
- Center for Bioimaging Sciences, Department of Biological Sciences, National University of Singapore, Singapore, 117543, Singapore
| | - Yumei Wang
- Beijing National Laboratory for Condensed Matter Physics, Institute of Physics, Chinese Academy of Science, Beijing, 100190, China
| | - Zongli Li
- Harvard Cryo-EM Center for Structural Biology, Harvard Medical School, Boston, MA, 02115, USA
| | - Radoslaw M Sobota
- Functional Proteomics Laboratory, SingMass National Laboratory, Institute of Molecular and Cell Biology, Agency for Science, Technology and Research (A*STAR), Singapore, 138673, Singapore
| | - Lok-To Sham
- Infectious Diseases Translational Research Programme and Department of Microbiology and Immunology, Yong Loo Lin School of Medicine, National University of Singapore, Singapore, 117545, Singapore.
| | - Min Luo
- Department of Biological Sciences, Faculty of Science, National University of Singapore, Singapore, 117543, Singapore.
- Center for Bioimaging Sciences, Department of Biological Sciences, National University of Singapore, Singapore, 117543, Singapore.
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3
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Structural insights into the catalytic cycle of a bacterial multidrug ABC efflux pump. J Mol Biol 2022; 434:167541. [DOI: 10.1016/j.jmb.2022.167541] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/19/2022] [Revised: 03/02/2022] [Accepted: 03/09/2022] [Indexed: 12/19/2022]
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Characterization of the nucleotide-binding domain NsrF from the BceAB-type ABC-transporter NsrFP from the human pathogen Streptococcus agalactiae. Sci Rep 2020; 10:15208. [PMID: 32938989 PMCID: PMC7494861 DOI: 10.1038/s41598-020-72237-7] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/19/2020] [Accepted: 08/27/2020] [Indexed: 01/14/2023] Open
Abstract
Treatment of bacterial infections is a great challenge of our era due to the various resistance mechanisms against antibiotics. Antimicrobial peptides are considered to be potential novel compound as antibiotic treatment. However, some bacteria, especially many human pathogens, are inherently resistant to these compounds, due to the expression of BceAB-type ABC transporters. This rather new transporter family is not very well studied. Here, we report the first full characterization of the nucleotide binding domain of a BceAB type transporter from Streptococcus agalactiae, namely SaNsrF of the transporter SaNsrFP, which confers resistance against nisin and gallidermin. We determined the NTP hydrolysis kinetics and used molecular modeling and simulations in combination with small angle X-ray scattering to obtain structural models of the SaNsrF monomer and dimer. The fact that the SaNsrFH202A variant displayed no ATPase activity was rationalized in terms of changes of the structural dynamics of the dimeric interface. Kinetic data show a clear preference for ATP as a substrate, and the prediction of binding modes allowed us to explain this selectivity over other NTPs.
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Izuhara K, Fukui K, Murakawa T, Baba S, Kumasaka T, Uchiyama K, Yano T. A Lynch syndrome-associated mutation at a Bergerat ATP-binding fold destabilizes the structure of the DNA mismatch repair endonuclease MutL. J Biol Chem 2020; 295:11643-11655. [PMID: 32571878 DOI: 10.1074/jbc.ra120.013576] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/24/2020] [Revised: 06/17/2020] [Indexed: 12/14/2022] Open
Abstract
In humans, mutations in genes encoding homologs of the DNA mismatch repair endonuclease MutL cause a hereditary cancer that is known as Lynch syndrome. Here, we determined the crystal structures of the N-terminal domain (NTD) of MutL from the thermophilic eubacterium Aquifex aeolicus (aqMutL) complexed with ATP analogs at 1.69-1.73 Å. The structures revealed significant structural similarities to those of a human MutL homolog, postmeiotic segregation increased 2 (PMS2). We introduced five Lynch syndrome-associated mutations clinically found in human PMS2 into the aqMutL NTD and investigated the protein stability, ATPase activity, and DNA-binding ability of these protein variants. Among the mutations studied, the most unexpected results were obtained for the residue Ser34. Ser34 (Ser46 in PMS2) is located at a previously identified Bergerat ATP-binding fold. We found that the S34I aqMutL NTD retains ATPase and DNA-binding activities. Interestingly, CD spectrometry and trypsin-limited proteolysis indicated the disruption of a secondary structure element of the S34I NTD, destabilizing the overall structure of the aqMutL NTD. In agreement with this, the recombinant human PMS2 S46I NTD was easily digested in the host Escherichia coli cells. Moreover, other mutations resulted in reduced DNA-binding or ATPase activity. In summary, using the thermostable aqMutL protein as a model molecule, we have experimentally determined the effects of the mutations on MutL endonuclease; we discuss the pathological effects of the corresponding mutations in human PMS2.
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Affiliation(s)
- Keisuke Izuhara
- Department of Biochemistry, Osaka Medical College, Takatsuki, Osaka, Japan.,Department of General and Gastroenterological Surgery, Osaka Medical College, Takatsuki, Osaka, Japan
| | - Kenji Fukui
- Department of Biochemistry, Osaka Medical College, Takatsuki, Osaka, Japan
| | - Takeshi Murakawa
- Department of Biochemistry, Osaka Medical College, Takatsuki, Osaka, Japan
| | - Seiki Baba
- Protein Crystal Analysis Division, Japan Synchrotron Radiation Research Institute, Hyogo, Japan
| | - Takashi Kumasaka
- Protein Crystal Analysis Division, Japan Synchrotron Radiation Research Institute, Hyogo, Japan
| | - Kazuhisa Uchiyama
- Department of General and Gastroenterological Surgery, Osaka Medical College, Takatsuki, Osaka, Japan
| | - Takato Yano
- Department of Biochemistry, Osaka Medical College, Takatsuki, Osaka, Japan
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Kieuvongngam V, Olinares PDB, Palillo A, Oldham ML, Chait BT, Chen J. Structural basis of substrate recognition by a polypeptide processing and secretion transporter. eLife 2020; 9:51492. [PMID: 31934861 PMCID: PMC6959990 DOI: 10.7554/elife.51492] [Citation(s) in RCA: 19] [Impact Index Per Article: 4.8] [Reference Citation Analysis] [Abstract] [Key Words] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/30/2019] [Accepted: 12/23/2019] [Indexed: 12/28/2022] Open
Abstract
The peptidase-containing ATP-binding cassette transporters (PCATs) are unique members of the ABC transporter family that proteolytically process and export peptides and proteins. Each PCAT contains two peptidase domains that cleave off the secretion signal, two transmembrane domains forming a translocation pathway, and two nucleotide-binding domains that hydrolyze ATP. Previously the crystal structures of a PCAT from Clostridium thermocellum (PCAT1) were determined in the absence and presence of ATP, revealing how ATP binding regulates the protease activity and access to the translocation pathway. However, how the substrate CtA, a 90-residue polypeptide, is recognized by PCAT1 remained elusive. To address this question, we determined the structure of the PCAT1-CtA complex by electron cryo-microscopy (cryo-EM) to 3.4 Å resolution. The structure shows that two CtAs are bound via their N-terminal leader peptides, but only one is positioned for cleavage and translocation. Based on these results, we propose a model of how substrate cleavage, ATP hydrolysis, and substrate translocation are coordinated in a transport cycle.
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Affiliation(s)
- Virapat Kieuvongngam
- Laboratory of Membrane Biophysics and Biology, The Rockefeller University, New York, United States
| | - Paul Dominic B Olinares
- Laboratory of Mass Spectrometry and Gaseous Ion Chemistry, The Rockefeller University, New York, United States
| | - Anthony Palillo
- Laboratory of Membrane Biophysics and Biology, The Rockefeller University, New York, United States
| | - Michael L Oldham
- Laboratory of Membrane Biophysics and Biology, The Rockefeller University, New York, United States.,Howard Hughes Medical Institute, Chevy Chase, United States
| | - Brian T Chait
- Laboratory of Mass Spectrometry and Gaseous Ion Chemistry, The Rockefeller University, New York, United States
| | - Jue Chen
- Laboratory of Membrane Biophysics and Biology, The Rockefeller University, New York, United States.,Howard Hughes Medical Institute, Chevy Chase, United States
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Diversified transporters and pathways for bacteriocin secretion in gram-positive bacteria. Appl Microbiol Biotechnol 2018; 102:4243-4253. [DOI: 10.1007/s00253-018-8917-5] [Citation(s) in RCA: 19] [Impact Index Per Article: 3.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/25/2018] [Revised: 03/05/2018] [Accepted: 03/06/2018] [Indexed: 10/17/2022]
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ATPase activity regulation by leader peptide processing of ABC transporter maturation and secretion protein, NukT, for lantibiotic nukacin ISK-1. Appl Microbiol Biotechnol 2017; 102:763-772. [DOI: 10.1007/s00253-017-8645-2] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/01/2017] [Revised: 11/09/2017] [Accepted: 11/12/2017] [Indexed: 10/18/2022]
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Abstract
The main components of the quorum-sensing system are expected to be favorable targets for drug development to combat various chronic infectious diseases. ComA of Streptococcus is an ATP-binding cassette transporter containing a peptidase domain (PEP), which is essential for the quorum-sensing signal production. Using high-throughput screening, we found a potent small molecule that suppressed the S. mutans quorum-sensing pathway through inhibition of PEP activity. The compound effectively attenuated the biofilm formation and competence development of S. mutans without inhibiting cell growth. The kinetic and structural studies with this molecule and a related compound unexpectedly revealed an allosteric site of PEP. This relatively hydrophobic site is thought to undergo large structural changes during the catalytic process. These compounds inhibit PEP activity by binding to and suppressing the structural changes of this site. These results showed that PEP is a good target for inhibitors of the Streptococcus quorum-sensing system.
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Abstract
Bacteria secrete peptides and proteins to communicate, to poison competitors, and to manipulate host cells. Among the various protein-translocation machineries, the peptidase-containing ATP-binding cassette transporters (PCATs) are appealingly simple. Each PCAT contains two peptidase domains that cleave the secretion signal from the substrate, two transmembrane domains that form a translocation pathway, and two nucleotide-binding domains that hydrolyse ATP. In Gram-positive bacteria, PCATs function both as maturation proteases and exporters for quorum-sensing or antimicrobial polypeptides. In Gram-negative bacteria, PCATs interact with two other membrane proteins to form the type 1 secretion system. Here we present crystal structures of PCAT1 from Clostridium thermocellum in two different conformations. These structures, accompanied by biochemical data, show that the translocation pathway is a large α-helical barrel sufficient to accommodate small folded proteins. ATP binding alternates access to the transmembrane pathway and also regulates the protease activity, thereby coupling substrate processing to translocation.
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Kaur G, Rajesh S, Princy SA. Plausible Drug Targets in the Streptococcus mutans Quorum Sensing Pathways to Combat Dental Biofilms and Associated Risks. Indian J Microbiol 2015; 55:349-56. [PMID: 26543259 DOI: 10.1007/s12088-015-0534-8] [Citation(s) in RCA: 39] [Impact Index Per Article: 4.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/09/2015] [Accepted: 05/08/2015] [Indexed: 12/31/2022] Open
Abstract
Streptococcus mutans, a Gram positive facultative anaerobe, is one among the approximately seven hundred bacterial species to exist in human buccal cavity and cause dental caries. Quorum sensing (QS) is a cell-density dependent communication process that respond to the inter/intra-species signals and elicit responses to show behavioral changes in the bacteria to an aggressive forms. In accordance to this phenomenon, the S. mutans also harbors a Competing Stimulating Peptide (CSP)-mediated quorum sensing, ComCDE (Two-component regulatory system) to regulate several virulence-associated traits that includes the formation of the oral biofilm (dental plaque), genetic competence and acidogenicity. The QS-mediated response of S. mutans adherence on tooth surface (dental plaque) imparts antibiotic resistance to the bacterium and further progresses to lead a chronic state, known as periodontitis. In recent years, the oral streptococci, S. mutans are not only recognized for its cariogenic potential but also well known to worsen the infective endocarditis due to its inherent ability to colonize and form biofilm on heart valves. The review significantly appreciate the increasing complexity of the CSP-mediated quorum-sensing pathway with a special emphasis to identify the plausible drug targets within the system for the development of anti-quorum drugs to control biofilm formation and associated risks.
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Affiliation(s)
- Gurmeet Kaur
- Quorum Sensing Laboratory, Centre for Research on Infectious Diseases (CRID), School of Chemical and Biotechnology, SASTRA University, Thanjavur, 613 402 Tamil Nadu India
| | - Shrinidhi Rajesh
- Quorum Sensing Laboratory, Centre for Research on Infectious Diseases (CRID), School of Chemical and Biotechnology, SASTRA University, Thanjavur, 613 402 Tamil Nadu India
| | - S Adline Princy
- Quorum Sensing Laboratory, Centre for Research on Infectious Diseases (CRID), School of Chemical and Biotechnology, SASTRA University, Thanjavur, 613 402 Tamil Nadu India
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