1
|
Sivaramalingam SS, Jothivel D, Govindarajan DK, Kadirvelu L, Sivaramakrishnan M, Chithiraiselvan DD, Kandaswamy K. Structural and functional insights of sortases and their interactions with antivirulence compounds. Curr Res Struct Biol 2024; 8:100152. [PMID: 38989133 PMCID: PMC11231552 DOI: 10.1016/j.crstbi.2024.100152] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/31/2023] [Revised: 05/18/2024] [Accepted: 06/11/2024] [Indexed: 07/12/2024] Open
Abstract
Sortase proteins play a crucial role as integral membrane proteins in anchoring bacterial surface proteins by recognizing them through a Cell-Wall Sorting (CWS) motif and cleaving them at specific sites before initiating pilus assembly. Both sortases and their substrate proteins are major virulence factors in numerous Gram-positive pathogens, making them attractive targets for antimicrobial intervention. Recognizing the significance of virulence proteins, a comprehensive exploration of their structural and functional characteristics is essential to enhance our understanding of pilus assembly in diverse Gram-positive bacteria. Therefore, this review article discusses the structural features of different classes of sortases and pilin proteins, primarily serving as substrates for sortase-assembled pili. Moreover, it thoroughly examines the molecular-level interactions between sortases and their inhibitors, providing insights from both structural and functional perspectives. In essence, this review article will provide a contemporary and complete understanding of both sortase pathways and various strategies to target them effectively to counteract the virulence.
Collapse
Affiliation(s)
- Sowmiya Sri Sivaramalingam
- Research Center for Excellence in Microscopy, Department of Biotechnology, Kumaraguru College of Technology, Coimbatore, 641049, Tamil Nadu, India
| | - Deepsikha Jothivel
- Research Center for Excellence in Microscopy, Department of Biotechnology, Kumaraguru College of Technology, Coimbatore, 641049, Tamil Nadu, India
| | - Deenadayalan Karaiyagowder Govindarajan
- Research Center for Excellence in Microscopy, Department of Biotechnology, Kumaraguru College of Technology, Coimbatore, 641049, Tamil Nadu, India
- School of Chemistry, Chemical Engineering and Biotechnology, Nanyang Technological University, Singapore
| | - Lohita Kadirvelu
- Research Center for Excellence in Microscopy, Department of Biotechnology, Kumaraguru College of Technology, Coimbatore, 641049, Tamil Nadu, India
| | - Muthusaravanan Sivaramakrishnan
- Research Center for Excellence in Microscopy, Department of Biotechnology, Kumaraguru College of Technology, Coimbatore, 641049, Tamil Nadu, India
- Department of Biotechnology, Mepco Schlenk Engineering College, Tamil Nadu, India
| | - Dhivia Dharshika Chithiraiselvan
- Research Center for Excellence in Microscopy, Department of Biotechnology, Kumaraguru College of Technology, Coimbatore, 641049, Tamil Nadu, India
| | - Kumaravel Kandaswamy
- Research Center for Excellence in Microscopy, Department of Biotechnology, Kumaraguru College of Technology, Coimbatore, 641049, Tamil Nadu, India
| |
Collapse
|
2
|
Eigenfeld M, Lupp KFM, Schwaminger SP. Role of Natural Binding Proteins in Therapy and Diagnostics. Life (Basel) 2024; 14:630. [PMID: 38792650 PMCID: PMC11122601 DOI: 10.3390/life14050630] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/31/2024] [Revised: 05/02/2024] [Accepted: 05/08/2024] [Indexed: 05/26/2024] Open
Abstract
This review systematically investigates the critical role of natural binding proteins (NBPs), encompassing DNA-, RNA-, carbohydrate-, fatty acid-, and chitin-binding proteins, in the realms of oncology and diagnostics. In an era where cancer continues to pose significant challenges to healthcare systems worldwide, the innovative exploration of NBPs offers a promising frontier for advancing both the diagnostic accuracy and therapeutic efficacy of cancer management strategies. This manuscript provides an in-depth examination of the unique mechanisms by which NBPs interact with specific molecular targets, highlighting their potential to revolutionize cancer diagnostics and therapy. Furthermore, it discusses the burgeoning research on aptamers, demonstrating their utility as 'nucleic acid antibodies' for targeted therapy and precision diagnostics. Despite the promising applications of NBPs and aptamers in enhancing early cancer detection and developing personalized treatment protocols, this review identifies a critical knowledge gap: the need for comprehensive studies to understand the diverse functionalities and therapeutic potentials of NBPs across different cancer types and diagnostic scenarios. By bridging this gap, this manuscript underscores the importance of NBPs and aptamers in paving the way for next-generation diagnostics and targeted cancer treatments.
Collapse
Affiliation(s)
- Marco Eigenfeld
- Otto-Loewi Research Center, Division of Medicinal Chemistry, Medical University of Graz, Neue Stiftingtalstraße 6, 8010 Graz, Austria
| | - Kilian F. M. Lupp
- Otto-Loewi Research Center, Division of Medicinal Chemistry, Medical University of Graz, Neue Stiftingtalstraße 6, 8010 Graz, Austria
| | - Sebastian P. Schwaminger
- Otto-Loewi Research Center, Division of Medicinal Chemistry, Medical University of Graz, Neue Stiftingtalstraße 6, 8010 Graz, Austria
- BioTechMed-Graz, Mozartgasse 12/II, 8010 Graz, Austria
| |
Collapse
|
3
|
Goossens PL. Bacillus anthracis, "la maladie du charbon", Toxins, and Institut Pasteur. Toxins (Basel) 2024; 16:66. [PMID: 38393144 PMCID: PMC10891547 DOI: 10.3390/toxins16020066] [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: 11/08/2023] [Revised: 12/25/2023] [Accepted: 12/30/2023] [Indexed: 02/25/2024] Open
Abstract
Institut Pasteur and Bacillus anthracis have enjoyed a relationship lasting almost 120 years, starting from its foundation and the pioneering work of Louis Pasteur in the nascent fields of microbiology and vaccination, and blooming after 1986 following the molecular biology/genetic revolution. This contribution will give a historical overview of these two research eras, taking advantage of the archives conserved at Institut Pasteur. The first era mainly focused on the production, characterisation, surveillance and improvement of veterinary anthrax vaccines; the concepts and technologies with which to reach a deep understanding of this research field were not yet available. The second period saw a new era of B. anthracis research at Institut Pasteur, with the anthrax laboratory developing a multi-disciplinary approach, ranging from structural analysis, biochemistry, genetic expression, and regulation to bacterial-host cell interactions, in vivo pathogenicity, and therapy development; this led to the comprehensive unravelling of many facets of this toxi-infection. B. anthracis may exemplify some general points on how science is performed in a given society at a given time and how a scientific research domain evolves. A striking illustration can be seen in the additive layers of regulations that were implemented from the beginning of the 21st century and their impact on B. anthracis research. B. anthracis and anthrax are complex systems that raise many valuable questions regarding basic research. One may hope that B. anthracis research will be re-initiated under favourable circumstances later at Institut Pasteur.
Collapse
|
4
|
Susmitha A, Bajaj H, Madhavan Nampoothiri K. The divergent roles of sortase in the biology of Gram-positive bacteria. ACTA ACUST UNITED AC 2021; 7:100055. [PMID: 34195501 PMCID: PMC8225981 DOI: 10.1016/j.tcsw.2021.100055] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/16/2021] [Revised: 06/11/2021] [Accepted: 06/11/2021] [Indexed: 12/16/2022]
Abstract
The bacterial cell wall contains numerous surface-exposed proteins, which are covalently anchored and assembled by a sortase family of transpeptidase enzymes. The sortase are cysteine transpeptidases that catalyzes the covalent attachment of surface protein to the cell wall peptidoglycan. Among the reported six classes of sortases, each distinct class of sortase plays a unique biological role in anchoring a variety of surface proteins to the peptidoglycan of both pathogenic and non-pathogenic Gram-positive bacteria. Sortases not only exhibit virulence and pathogenesis properties to host cells, but also possess a significant role in gut retention and immunomodulation in probiotic microbes. The two main distinct functions are to attach proteins directly to the cell wall or assemble pili on the microbial surface. This review provides a compendium of the distribution of different classes of sortases present in both pathogenic and non-pathogenic Gram-positive bacteria and also the noteworthy role played by them in bacterial cell wall assembly which enables each microbe to effectively interact with its environment.
Collapse
Affiliation(s)
- Aliyath Susmitha
- Microbial Processes and Technology Division, CSIR - National Institute for Interdisciplinary Science and Technology (NIIST), Trivandrum 695019, Kerala, India.,Academy of Scientific and Innovative Research (AcSIR), Ghaziabad 201002, India
| | - Harsha Bajaj
- Microbial Processes and Technology Division, CSIR - National Institute for Interdisciplinary Science and Technology (NIIST), Trivandrum 695019, Kerala, India
| | - Kesavan Madhavan Nampoothiri
- Microbial Processes and Technology Division, CSIR - National Institute for Interdisciplinary Science and Technology (NIIST), Trivandrum 695019, Kerala, India.,Academy of Scientific and Innovative Research (AcSIR), Ghaziabad 201002, India
| |
Collapse
|
5
|
Chateau A, Van der Verren SE, Remaut H, Fioravanti A. The Bacillus anthracis Cell Envelope: Composition, Physiological Role, and Clinical Relevance. Microorganisms 2020; 8:E1864. [PMID: 33255913 PMCID: PMC7759979 DOI: 10.3390/microorganisms8121864] [Citation(s) in RCA: 9] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/09/2020] [Revised: 11/23/2020] [Accepted: 11/24/2020] [Indexed: 12/31/2022] Open
Abstract
Anthrax is a highly resilient and deadly disease caused by the spore-forming bacterial pathogen Bacillus anthracis. The bacterium presents a complex and dynamic composition of its cell envelope, which changes in response to developmental and environmental conditions and host-dependent signals. Because of their easy to access extracellular locations, B. anthracis cell envelope components represent interesting targets for the identification and development of novel therapeutic and vaccine strategies. This review will focus on the novel insights regarding the composition, physiological role, and clinical relevance of B. anthracis cell envelope components.
Collapse
Affiliation(s)
- Alice Chateau
- Avignon Université, INRAE, UMR SQPOV, F-84914 Avignon, France;
| | - Sander E. Van der Verren
- Structural and Molecular Microbiology, Structural Biology Research Center, VIB, 1050 Brussels, Belgium; (S.E.V.d.V.); (H.R.)
- Structural Biology Brussels, Vrije Universiteit Brussel, 1050 Brussels, Belgium
| | - Han Remaut
- Structural and Molecular Microbiology, Structural Biology Research Center, VIB, 1050 Brussels, Belgium; (S.E.V.d.V.); (H.R.)
- Structural Biology Brussels, Vrije Universiteit Brussel, 1050 Brussels, Belgium
| | - Antonella Fioravanti
- Structural and Molecular Microbiology, Structural Biology Research Center, VIB, 1050 Brussels, Belgium; (S.E.V.d.V.); (H.R.)
- Structural Biology Brussels, Vrije Universiteit Brussel, 1050 Brussels, Belgium
| |
Collapse
|
6
|
Miller OK, Banfield MJ, Schwarz-Linek U. A new structural class of bacterial thioester domains reveals a slipknot topology. Protein Sci 2018; 27:1651-1660. [PMID: 30052296 PMCID: PMC6194298 DOI: 10.1002/pro.3478] [Citation(s) in RCA: 12] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/02/2018] [Revised: 06/28/2018] [Accepted: 06/28/2018] [Indexed: 11/11/2022]
Abstract
An increasing number of surface-associated proteins identified in Gram-positive bacteria are characterized by intramolecular cross-links in structurally conserved thioester, isopeptide, and ester domains (TIE proteins). Two classes of thioester domains (TEDs) have been predicted based on sequence with, to date, only representatives of Class I structurally characterized. Here, we present crystal structures of three Class II TEDs from Bacillus anthracis, vancomycin-resistant Staphylococcus aureus, and vancomycin-resistant Enterococcus faecium. These proteins are structurally distinct from Class I TEDs due to a β-sandwich domain that is inserted into the conserved TED fold to form a slipknot structure. Further, the B. anthracis TED domain is presented in the context of a full-length sortase-anchored protein structure (BaTIE). This provides insight into the three-dimensional arrangement of TIE proteins, which emerge as very abundant putative adhesins of Gram-positive bacteria.
Collapse
Affiliation(s)
- Ona K Miller
- Biomedical Sciences Research Complex and School of Biology, University of St Andrews, St Andrews, KY16 9ST, United Kingdom
| | - Mark J Banfield
- John Innes Centre, Department of Biological Chemistry, Norwich Research Park, Norwich, NR4 7UH, United Kingdom
| | - Ulrich Schwarz-Linek
- Biomedical Sciences Research Complex and School of Biology, University of St Andrews, St Andrews, KY16 9ST, United Kingdom
| |
Collapse
|
7
|
Disparate subcellular location of putative sortase substrates in Clostridium difficile. Sci Rep 2017; 7:9204. [PMID: 28835650 PMCID: PMC5569036 DOI: 10.1038/s41598-017-08322-1] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/08/2017] [Accepted: 07/07/2017] [Indexed: 12/18/2022] Open
Abstract
Clostridium difficile is a gastrointestinal pathogen but how the bacterium colonises this niche is still little understood. Sortase enzymes covalently attach specific bacterial proteins to the peptidoglycan cell wall and are often involved in colonisation by pathogens. Here we show C. difficile proteins CD2537 and CD3392 are functional substrates of sortase SrtB. Through manipulation of the C-terminal regions of these proteins we show the SPKTG motif is essential for covalent attachment to the cell wall. Two additional putative substrates, CD0183 which contains an SPSTG motif, and CD2768 which contains an SPQTG motif, are not cleaved or anchored to the cell wall by sortase. Finally, using an in vivo asymmetric cleavage assay, we show that despite containing a conserved SPKTG motif, in the absence of SrtB these proteins are localised to disparate cellular compartments.
Collapse
|
8
|
Chan AH, Yi SW, Terwilliger AL, Maresso AW, Jung ME, Clubb RT. Structure of the Bacillus anthracis Sortase A Enzyme Bound to Its Sorting Signal: A FLEXIBLE AMINO-TERMINAL APPENDAGE MODULATES SUBSTRATE ACCESS. J Biol Chem 2015; 290:25461-74. [PMID: 26324714 DOI: 10.1074/jbc.m115.670984] [Citation(s) in RCA: 18] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/08/2015] [Indexed: 12/31/2022] Open
Abstract
The endospore forming bacterium Bacillus anthracis causes lethal anthrax disease in humans and animals. The ability of this pathogen to replicate within macrophages is dependent upon the display of bacterial surface proteins attached to the cell wall by the B. anthracis Sortase A ((Ba)SrtA) enzyme. Previously, we discovered that the class A (Ba)SrtA sortase contains a unique N-terminal appendage that wraps around the body of the protein to contact the active site of the enzyme. To gain insight into its function, we determined the NMR structure of (Ba)SrtA bound to a LPXTG sorting signal analog. The structure, combined with dynamics, kinetics, and whole cell protein display data suggest that the N terminus modulates substrate access to the enzyme. We propose that it may increase the efficiency of protein display by reducing the unproductive hydrolytic cleavage of enzyme-protein covalent intermediates that form during the cell wall anchoring reaction. Notably, a key active site loop (β7/β8 loop) undergoes a disordered to ordered transition upon binding the sorting signal, potentially facilitating recognition of lipid II.
Collapse
Affiliation(s)
- Albert H Chan
- From the Department of Chemistry and Biochemistry, UCLA-DOE Institute of Genomics and Proteomics, and the Molecular Biology Institute, University of California, Los Angeles, California 90095 and
| | - Sung Wook Yi
- From the Department of Chemistry and Biochemistry
| | - Austen L Terwilliger
- the Department of Molecular Virology and Microbiology, Baylor College of Medicine, Houston, Texas 77030
| | - Anthony W Maresso
- the Department of Molecular Virology and Microbiology, Baylor College of Medicine, Houston, Texas 77030
| | | | - Robert T Clubb
- From the Department of Chemistry and Biochemistry, UCLA-DOE Institute of Genomics and Proteomics, and the Molecular Biology Institute, University of California, Los Angeles, California 90095 and
| |
Collapse
|
9
|
Structure and function of a Clostridium difficile sortase enzyme. Sci Rep 2015; 5:9449. [PMID: 25801974 PMCID: PMC4371152 DOI: 10.1038/srep09449] [Citation(s) in RCA: 19] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/26/2015] [Accepted: 03/05/2015] [Indexed: 01/20/2023] Open
Abstract
Sortase enzymes are responsible for covalent anchoring of specific proteins to the peptidoglycan of the cell wall of gram-positive bacteria. In some gram-positive bacteria (e.g. Staphylococcus aureus), sortases have been found to be essential for pathogenesis and their inhibitors are under development as potential novel therapeutics. Here we provide the first report on the structural characterisation of the C. difficile sortase. An active site mutant was crystallised and its structure determined to 2.55 Å by X-ray diffraction to provide structural insight into its catalytic mechanism. In order to elucidate the role of the sortase in the cell wall biogenesis, a C. difficile sortase knockout strain was constructed by intron mutagenesis. Characterisation of this mutant led to the discovery that the putative adhesin CD0386 is anchored to the peptidoglycan of C. difficile by the sortase SrtB and that an SPKTG peptide motif is involved in the transpeptidation reaction with the C. difficile peptidoglycan. In an animal model for C. difficile infection, the SrtB mutant caused disease at a similar rate of onset as the wild type strain. In conclusion, our detailed study shows that the SrtB enzyme from C. difficile does not play an essential role in pathogenesis.
Collapse
|
10
|
Candela T, Balomenou S, Aucher W, Bouriotis V, Simore JP, Fouet A, Boneca IG. N-acetylglucosamine deacetylases modulate the anchoring of the gamma-glutamyl capsule to the cell wall of Bacillus anthracis. Microb Drug Resist 2014; 20:222-30. [PMID: 24833281 DOI: 10.1089/mdr.2014.0063] [Citation(s) in RCA: 15] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/28/2023] Open
Abstract
Bacillus anthracis has a complex cell wall structure composed of a peptidoglycan (PG) layer to which major structures are anchored such as a neutral polysaccharide, an S-layer, and a poly-γ-D-glutamate (PDGA) capsule. Many of these structures have central roles in the biology of B. anthracis, particularly, in virulence. However, little attention has been devoted to structurally study the PG and how it is modified in the presence of these secondary cell wall components. We present here the fine structure of the PG of the encapsulated RPG1 strain harboring both pXO1 and pXO2 virulence plasmids. We show that B. anthracis has a high degree of cross-linking and its GlcNAc residues are highly modified by N-deacetylation. The PG composition is not dependent on the presence of either LPXTG proteins or the capsule. Using NMR analysis of the PG-PDGA complex, we provide evidence for the anchoring of the PDGA to the glucosamine residues. We show that anchoring of the PDGA capsule is impaired in two PG N-deacetylase mutants, Ba1961 and Ba3679. Thus, these multiple N-deactylase activities would constitute excellent drug targets in B. anthracis by simultaneously affecting its resistance to lysozyme and to phagocytosis impairing B. anthracis survival in the host.
Collapse
Affiliation(s)
- Thomas Candela
- 1 Institut Pasteur , Unité Toxines et Pathogénie Bactérienne, Paris, France
| | | | | | | | | | | | | |
Collapse
|
11
|
Selvaraj C, Sivakamavalli J, Baskaralingam V, Singh SK. Virtual screening of LPXTG competitive SrtA inhibitors targeting signal transduction mechanism in Bacillus anthracis: a combined experimental and theoretical study. J Recept Signal Transduct Res 2014; 34:221-32. [PMID: 24490975 DOI: 10.3109/10799893.2013.876044] [Citation(s) in RCA: 12] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/29/2022]
Abstract
Members of the sortase enzyme super family decorate the surfaces of Bacillus anthracis cell wall with proteins that play key roles in microbial pathogenesis and its biofilm formation. Bacillus anthracis Sortase-A (Ba-SrtA) is a potential target for new therapeutics as it is required for B. anthracis survival and replication within macrophages. An understanding of the binding site pocket and substrate recognition mechanism by SrtA enzymes may serve to be beneficial in the rational development of sortase inhibitors. Here, the LPXTG signal peptide-based competitive inhibitors are screened against the Ba-SrtA and compounds with reasonable inhibition, specificity, and mechanisms of inactivation of SrtA have been covered. The screened compounds are experimentally validated against the phylogenetically similar Gram-positive pathogen B. cereus. In situ microscopic visualizations suggest that these screened compounds showed the microbial and biofilm inhibitory activity against B. cereus. It facilitates the further development of these molecules into useful anti-infective agents to treat infections caused by B. anthracis and other Gram-positive pathogens. These results provide insight into basic design principles for generating new clinically relevant lead molecules. It also provides an alternative strategy where a screened ligand molecule can be used in combination to battle increasingly against the Gram-positive pathogens.
Collapse
Affiliation(s)
- Chandrabose Selvaraj
- Computer Aided Drug Design and Molecular Modeling Lab, Department of Bioinformatics, Alagappa University , Karaikudi, Tamil Nadu , India and
| | | | | | | |
Collapse
|
12
|
Abhyankar W, Hossain AH, Djajasaputra A, Permpoonpattana P, Ter Beek A, Dekker HL, Cutting SM, Brul S, de Koning LJ, de Koster CG. In Pursuit of Protein Targets: Proteomic Characterization of Bacterial Spore Outer Layers. J Proteome Res 2013; 12:4507-21. [DOI: 10.1021/pr4005629] [Citation(s) in RCA: 59] [Impact Index Per Article: 5.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/30/2022]
Affiliation(s)
| | | | | | - Patima Permpoonpattana
- School
of Biological Sciences, Royal Holloway, University of London, Egham, Surrey TW20 0EX, United Kingdom
| | | | | | - Simon M. Cutting
- School
of Biological Sciences, Royal Holloway, University of London, Egham, Surrey TW20 0EX, United Kingdom
| | | | | | | |
Collapse
|
13
|
Selvaraj C, Singh SK. Validation of potential inhibitors for SrtA against Bacillus anthracis by combined approach of ligand-based and molecular dynamics simulation. J Biomol Struct Dyn 2013; 32:1333-49. [PMID: 23869520 DOI: 10.1080/07391102.2013.818577] [Citation(s) in RCA: 24] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/26/2022]
Abstract
The development of SrtA inhibitors targeting the biothreat organism namely Bacillus anthracis was achieved by the combined approach of pharmacophore modeling, binding interactions, electron transferring capacity, ADME, and Molecular dynamics studies. In this study, experimentally reported Ba-SrtA inhibitors (pyridazinone and pyrazolethione derivatives) were considered for the development of enhanced pharmacophoric model. The obtained AAAHR hypothesis was a pure theoretical concept that accounts for common molecular interaction network present in experimentally active pyridazinone and pyrazolethione derivatives. Pharmacophore-based screening of AAAHR hypothesis provides several new compounds, and those compounds were treated with four phases of docking protocols with combined Glide-QPLD docking approach. In this approach, scoring and charge accuracy variations were seen to be dominated by QM/MM approach through the allocation of partial charges. Finally, we reported the best compounds from binding db, Chembridge db, and Toslab based on scoring values, energy parameters, electron transfer reaction, ADME, and cell adhesion inhibition activity. The dynamic state of interaction and binding energy assess that new compounds are more active inside the binding pocket and these compounds on experimental validations will survive as better inhibitors for targeting the cell adhesion mechanism of Ba-SrtA.
Collapse
Affiliation(s)
- Chandrabose Selvaraj
- a Computer Aided Drug Design and Molecular Modeling Lab, Department of Bioinformatics, Science Block , Alagappa University , Karaikudi 630004 , Tamilnadu , India
| | | |
Collapse
|
14
|
Candela T, Dumetz F, Tosi-Couture E, Mock M, Goossens PL, Fouet A. Cell-wall preparation containing poly-γ-D-glutamate covalently linked to peptidoglycan, a straightforward extractable molecule, protects mice against experimental anthrax infection. Vaccine 2012; 31:171-5. [PMID: 23122993 DOI: 10.1016/j.vaccine.2012.10.071] [Citation(s) in RCA: 11] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/28/2012] [Revised: 09/21/2012] [Accepted: 10/20/2012] [Indexed: 10/27/2022]
Abstract
Bacillus anthracis is the causative agent of anthrax that is characterized by septicemia and toxemia. Many vaccine strategies were described to counteract anthrax infection. In contrast with veterinary live vaccines, currently human vaccines are acellular with the protective antigen, a toxin component, as the main constituent. However, in animal models this vaccine is less efficient than the live vaccine. In this study, we analyzed the protection afforded by a single extractable surface element. The poly-γ-D-glutamate capsule is covalently linked to the peptidoglycan. A preparation of peptidoglycan-linked poly-γ-D-glutamate (GluPG) was tested for its immunogenicity and its protective effect. GluPG injection, in mice, elicited the production of specific antibodies directed against poly-glutamate and partially protected the animals against lethal challenges with a non-toxinogenic strain. When combined to protective antigen, GluPG immunization conferred full protection against cutaneous anthrax induced with a fully virulent strain.
Collapse
Affiliation(s)
- Thomas Candela
- Institut Pasteur, Toxines et Pathogénie Bactériennes, 25 rue du Dr Roux, 75015 Paris, France.
| | | | | | | | | | | |
Collapse
|
15
|
Robson SA, Jacobitz AW, Phillips ML, Clubb RT. Solution structure of the sortase required for efficient production of infectious Bacillus anthracis spores. Biochemistry 2012; 51:7953-63. [PMID: 22974341 DOI: 10.1021/bi300867t] [Citation(s) in RCA: 12] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
Abstract
Bacillus anthracis forms metabolically dormant endospores that upon germination can cause lethal anthrax disease in humans. Efficient sporulation requires the activity of the SrtC sortase (BaSrtC), a cysteine transpeptidase that covalently attaches the BasH and BasI proteins to the peptidoglycan of the forespore and predivisional cell, respectively. To gain insight into the molecular basis of protein display, we used nuclear magnetic resonance to determine the structure and backbone dynamics of the catalytic domain of BaSrtC (residues Ser(56)-Lys(198)). The backbone and heavy atom coordinates of structurally ordered amino acids have coordinate precision of 0.42 ± 0.07 and 0.82 ± 0.05 Å, respectively. BaSrtC(Δ55) adopts an eight-stranded β-barrel fold that contains two short helices positioned on opposite sides of the protein. Surprisingly, the protein dimerizes and contains an extensive, structurally disordered surface that is positioned adjacent to the active site. The surface is formed by two loops (β2-β3 and β4-H1 loops) that surround the active site histidine, suggesting that they may play a key role in associating BaSrtC with its lipid II substrate. BaSrtC anchors proteins bearing a noncanonical LPNTA sorting signal. Modeling studies suggest that the enzyme recognizes this substrate using a rigid binding pocket and reveals the presence of a conserved subsite for the signal. This first structure of a class D member of the sortase superfamily unveils class-specific features that may facilitate ongoing efforts to discover sortase inhibitors for the treatment of bacterial infections.
Collapse
Affiliation(s)
- Scott A Robson
- Department of Chemistry and Biochemistry, University of California, Los Angeles , 611 Charles Young Drive East, Los Angeles, California 90095, USA
| | | | | | | |
Collapse
|