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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] [What about the content of this article? (0)] [Affiliation(s)] [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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Su T, Chua WZ, Liu Y, Fan J, Tan SY, Yang DW, Sham LT. Rewiring the pneumococcal capsule pathway for investigating glycosyltransferase specificity and genetic glycoengineering. Sci Adv 2023; 9:eadi8157. [PMID: 37672581 PMCID: PMC10482335 DOI: 10.1126/sciadv.adi8157] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 05/19/2023] [Accepted: 08/03/2023] [Indexed: 09/08/2023]
Abstract
Virtually all living cells are covered with glycans. Their structures are primarily controlled by the specificities of glycosyltransferases (GTs). GTs typically adopt one of the three folds, namely, GT-A, GT-B, and GT-C. However, what defines their specificities remain poorly understood. Here, we developed a genetic glycoengineering platform by reprogramming the capsular polysaccharide pathways in Streptococcus pneumoniae to interrogate GT specificity and manipulate glycan structures. Our findings suggest that the central cleft of GT-B enzymes is important for determining acceptor specificity. The constraint of the glycoengineering platform was partially alleviated when the specificity of the precursor transporter was reduced, indicating that the transporter contributes to the overall fidelity of glycan synthesis. We also modified the pneumococcal capsule to produce several medically important mammalian glycans, as well as demonstrated the importance of regiochemistry in a glycosidic linkage on binding lung epithelial cells. Our work provided mechanistic insights into GT specificity and an approach for investigating glycan functions.
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Affiliation(s)
- Tong Su
- Infectious Diseases Translational Research Programme and Department of Microbiology and Immunology, Yong Loo Lin School of Medicine, National University of Singapore, Singapore 117545, 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
| | - Yao Liu
- Infectious Diseases Translational Research Programme and Department of Microbiology and Immunology, Yong Loo Lin School of Medicine, National University of Singapore, Singapore 117545, Singapore
| | - Jingsong Fan
- Department of Biological Sciences, Faculty of Science, National University of Singapore, Singapore 117545, Singapore
| | - Si-Yin Tan
- Infectious Diseases Translational Research Programme and Department of Microbiology and Immunology, Yong Loo Lin School of Medicine, National University of Singapore, Singapore 117545, Singapore
| | - Dai-wen Yang
- Department of Biological Sciences, Faculty of Science, National University of Singapore, Singapore 117545, 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
- Infectious Diseases Translational Research Programme and Department of Microbiology and Immunology, Yong Loo Lin School of Medicine, National University of Singapore, Singapore 117545, Singapore
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Xu X, Li J, Chua WZ, Pages MA, Shi J, Hermoso JA, Bernhardt T, Sham LT, Luo M. Mechanistic insights into the regulation of cell wall hydrolysis by FtsEX and EnvC at the bacterial division site. Proc Natl Acad Sci U S A 2023; 120:e2301897120. [PMID: 37186861 PMCID: PMC10214136 DOI: 10.1073/pnas.2301897120] [Citation(s) in RCA: 3] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/02/2023] [Accepted: 04/08/2023] [Indexed: 05/17/2023] Open
Abstract
The peptidoglycan (PG) cell wall produced by the bacterial division machinery is initially shared between the daughters and must be split to promote cell separation and complete division. In gram-negative bacteria, enzymes that cleave PG called amidases play major roles in the separation process. To prevent spurious cell wall cleavage that can lead to cell lysis, amidases like AmiB are autoinhibited by a regulatory helix. Autoinhibition is relieved at the division site by the activator EnvC, which is in turn regulated by the ATP-binding cassette (ABC) transporter-like complex called FtsEX. EnvC is also known to be autoinhibited by a regulatory helix (RH), but how its activity is modulated by FtsEX and the mechanism by which it activates the amidases have remained unclear. Here, we investigated this regulation by determining the structure of Pseudomonas aeruginosa FtsEX alone with or without bound ATP, in complex with EnvC, and in a FtsEX-EnvC-AmiB supercomplex. In combination with biochemical studies, the structures reveal that ATP binding is likely to activate FtsEX-EnvC and promote its association with AmiB. Furthermore, the AmiB activation mechanism is shown to involve a RH rearrangement. In the activated state of the complex, the inhibitory helix of EnvC is released, freeing it to associate with the RH of AmiB, which liberates its active site for PG cleavage. These regulatory helices are found in many EnvC proteins and amidases throughout gram-negative bacteria, suggesting that the activation mechanism is broadly conserved and a potential target for lysis-inducing antibiotics that misregulate the complex.
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Affiliation(s)
- Xin Xu
- Department of Biological Sciences, Faculty of Science, National University of Singapore, Singapore117543
| | - Jianwei Li
- Department of Biological Sciences, Faculty of Science, National University of Singapore, Singapore117543
| | - Wan-Zhen Chua
- Infectious Diseases Translational Research Programme, Yong Loo Lin School of Medicine, National University of Singapore, Singapore117545, Singapore
- Department of Microbiology and Immunology, Yong Loo Lin School of Medicine, National University of Singapore, Singapore117545, Singapore
| | - Martin A. Pages
- Department of Crystallography and Structural Biology, Instituto de Química-Física “Rocasolano”, Consejo Superior de Investigaciones Científicas, Madrid28006, Spain
| | - Jian Shi
- Center for Bioimaging Sciences, Department of Biological Sciences, National University of Singapore117543
| | - Juan A. Hermoso
- Department of Crystallography and Structural Biology, Instituto de Química-Física “Rocasolano”, Consejo Superior de Investigaciones Científicas, Madrid28006, Spain
| | - Thomas Bernhardt
- Department of Microbiology, Blavatnik Institute, Harvard Medical School, Boston, MA02115
- HHMI, MA02115, Boston
| | - Lok-To Sham
- Infectious Diseases Translational Research Programme, Yong Loo Lin School of Medicine, National University of Singapore, Singapore117545, Singapore
- Department of Microbiology and Immunology, Yong Loo Lin School of Medicine, National University of Singapore, Singapore117545, Singapore
| | - Min Luo
- Department of Biological Sciences, Faculty of Science, National University of Singapore, Singapore117543
- Center for Bioimaging Sciences, Department of Biological Sciences, National University of Singapore117543
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Chun YY, Tan KS, Yu L, Pang M, Wong MHM, Nakamoto R, Chua WZ, Huee-Ping Wong A, Lew ZZR, Ong HH, Chow VT, Tran T, Yun Wang D, Sham LT. Influence of glycan structure on the colonization of Streptococcus pneumoniae on human respiratory epithelial cells. Proc Natl Acad Sci U S A 2023; 120:e2213584120. [PMID: 36943879 PMCID: PMC10068763 DOI: 10.1073/pnas.2213584120] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/08/2022] [Accepted: 02/10/2023] [Indexed: 03/23/2023] Open
Abstract
Virtually all living cells are encased in glycans. They perform key cellular functions such as immunomodulation and cell-cell recognition. Yet, how their composition and configuration affect their functions remains enigmatic. Here, we constructed isogenic capsule-switch mutants harboring 84 types of capsular polysaccharides (CPSs) in Streptococcus pneumoniae. This collection enables us to systematically measure the affinity of structurally related CPSs to primary human nasal and bronchial epithelial cells. Contrary to the paradigm, the surface charge does not appreciably affect epithelial cell binding. Factors that affect adhesion to respiratory cells include the number of rhamnose residues and the presence of human-like glycomotifs in CPS. Besides, pneumococcal colonization stimulated the production of interleukin 6 (IL-6), granulocyte-macrophage colony-stimulating factor (GM-CSF), and monocyte chemoattractantprotein-1 (MCP-1) in nasal epithelial cells, which also appears to be dependent on the serotype. Together, our results reveal glycomotifs of surface polysaccharides that are likely to be important for colonization and survival in the human airway.
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Affiliation(s)
- Ye-Yu Chun
- Infectious Diseases Translational Research Programme, Yong Loo Lin School of Medicine, National University of Singapore, Singapore117545
- Department of Microbiology and Immunology, Yong Loo Lin School of Medicine, National University of Singapore, Singapore117545
| | - Kai Sen Tan
- Infectious Diseases Translational Research Programme, Yong Loo Lin School of Medicine, National University of Singapore, Singapore117545
- Department of Microbiology and Immunology, Yong Loo Lin School of Medicine, National University of Singapore, Singapore117545
- Department of Otolaryngology, Yong Loo Lin School of Medicine, National University of Singapore, Singapore117597
| | - Lisa Yu
- Infectious Diseases Translational Research Programme, Yong Loo Lin School of Medicine, National University of Singapore, Singapore117545
- Department of Microbiology and Immunology, Yong Loo Lin School of Medicine, National University of Singapore, Singapore117545
- College of Art and Sciences, Cornell University, Ithaca, NY14853
| | - Michelle Pang
- Infectious Diseases Translational Research Programme, Yong Loo Lin School of Medicine, National University of Singapore, Singapore117545
- Department of Microbiology and Immunology, Yong Loo Lin School of Medicine, National University of Singapore, Singapore117545
| | - Ming Hui Millie Wong
- Infectious Diseases Translational Research Programme, Yong Loo Lin School of Medicine, National University of Singapore, Singapore117545
- Department of Microbiology and Immunology, Yong Loo Lin School of Medicine, National University of Singapore, Singapore117545
| | - Rei Nakamoto
- Infectious Diseases Translational Research Programme, Yong Loo Lin School of Medicine, National University of Singapore, Singapore117545
- Department of Microbiology and Immunology, Yong Loo Lin School of Medicine, National University of Singapore, Singapore117545
| | - Wan-Zhen Chua
- Infectious Diseases Translational Research Programme, Yong Loo Lin School of Medicine, National University of Singapore, Singapore117545
- Department of Microbiology and Immunology, Yong Loo Lin School of Medicine, National University of Singapore, Singapore117545
| | - Amanda Huee-Ping Wong
- Infectious Diseases Translational Research Programme, Yong Loo Lin School of Medicine, National University of Singapore, Singapore117545
- Department of Microbiology and Immunology, Yong Loo Lin School of Medicine, National University of Singapore, Singapore117545
- Department of Physiology, Yong Loo Lin School of Medicine, National University of Singapore, Singapore117593
| | - Zhe Zhang Ryan Lew
- Infectious Diseases Translational Research Programme, Yong Loo Lin School of Medicine, National University of Singapore, Singapore117545
- Department of Microbiology and Immunology, Yong Loo Lin School of Medicine, National University of Singapore, Singapore117545
| | - Hsiao Hui Ong
- Infectious Diseases Translational Research Programme, Yong Loo Lin School of Medicine, National University of Singapore, Singapore117545
- Department of Microbiology and Immunology, Yong Loo Lin School of Medicine, National University of Singapore, Singapore117545
| | - Vincent T. Chow
- Infectious Diseases Translational Research Programme, Yong Loo Lin School of Medicine, National University of Singapore, Singapore117545
- Department of Microbiology and Immunology, Yong Loo Lin School of Medicine, National University of Singapore, Singapore117545
| | - Thai Tran
- Infectious Diseases Translational Research Programme, Yong Loo Lin School of Medicine, National University of Singapore, Singapore117545
- Department of Microbiology and Immunology, Yong Loo Lin School of Medicine, National University of Singapore, Singapore117545
- Department of Physiology, Yong Loo Lin School of Medicine, National University of Singapore, Singapore117593
| | - De Yun Wang
- Infectious Diseases Translational Research Programme, Yong Loo Lin School of Medicine, National University of Singapore, Singapore117545
- Department of Microbiology and Immunology, Yong Loo Lin School of Medicine, National University of Singapore, Singapore117545
| | - Lok-To Sham
- Infectious Diseases Translational Research Programme, Yong Loo Lin School of Medicine, National University of Singapore, Singapore117545
- Department of Microbiology and Immunology, Yong Loo Lin School of Medicine, National University of Singapore, Singapore117545
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