1
|
Hogan AM, Motnenko A, Rahman ASMZ, Cardona ST. Cell envelope structural and functional contributions to antibiotic resistance in Burkholderia cenocepacia. J Bacteriol 2024; 206:e0044123. [PMID: 38501654 PMCID: PMC11025338 DOI: 10.1128/jb.00441-23] [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: 12/29/2023] [Accepted: 03/05/2024] [Indexed: 03/20/2024] Open
Abstract
Antibiotic activity is limited by the physical construction of the Gram-negative cell envelope. Species of the Burkholderia cepacia complex (Bcc) are known as intrinsically multidrug-resistant opportunistic pathogens with low permeability cell envelopes. Here, we re-examined a previously performed chemical-genetic screen of barcoded transposon mutants in B. cenocepacia K56-2, focusing on cell envelope structural and functional processes. We identified structures mechanistically important for resistance to singular and multiple antibiotic classes. For example, susceptibility to novobiocin, avibactam, and the LpxC inhibitor, PF-04753299, was linked to the BpeAB-OprB efflux pump, suggesting these drugs are substrates for this pump in B. cenocepacia. Defects in peptidoglycan precursor synthesis specifically increased susceptibility to cycloserine and revealed a new putative amino acid racemase, while defects in divisome accessory proteins increased susceptibility to multiple β-lactams. Additionally, disruption of the periplasmic disulfide bond formation system caused pleiotropic defects on outer membrane integrity and β-lactamase activity. Our findings highlight the layering of resistance mechanisms in the structure and function of the cell envelope. Consequently, we point out processes that can be targeted for developing antibiotic potentiators.IMPORTANCEThe Gram-negative cell envelope is a double-layered physical barrier that protects cells from extracellular stressors, such as antibiotics. The Burkholderia cell envelope is known to contain additional modifications that reduce permeability. We investigated Burkholderia cell envelope factors contributing to antibiotic resistance from a genome-wide view by re-examining data from a transposon mutant library exposed to an antibiotic panel. We identified susceptible phenotypes for defects in structures and functions in the outer membrane, periplasm, and cytoplasm. Overall, we show that resistance linked to the cell envelope is multifaceted and provides new targets for the development of antibiotic potentiators.
Collapse
Affiliation(s)
- Andrew M. Hogan
- Department of Microbiology, University of Manitoba, Winnipeg, Manitoba, Canada
| | - Anna Motnenko
- Department of Microbiology, University of Manitoba, Winnipeg, Manitoba, Canada
| | | | - Silvia T. Cardona
- Department of Microbiology, University of Manitoba, Winnipeg, Manitoba, Canada
- Department of Medical Microbiology and Infectious Diseases, University of Manitoba, Winnipeg, Manitoba, Canada
| |
Collapse
|
2
|
Kadeřábková N, Furniss RCD, Maslova E, Eisaiankhongi L, Bernal P, Filloux A, Landeta C, Gonzalez D, McCarthy RR, Mavridou DA. Antibiotic potentiation and inhibition of cross-resistance in pathogens associated with cystic fibrosis. BIORXIV : THE PREPRINT SERVER FOR BIOLOGY 2023:2023.08.02.551661. [PMID: 37577508 PMCID: PMC10418187 DOI: 10.1101/2023.08.02.551661] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 08/15/2023]
Abstract
Critical Gram-negative pathogens, like Pseudomonas, Stenotrophomonas and Burkholderia, have become resistant to most antibiotics. Complex resistance profiles together with synergistic interactions between these organisms increase the likelihood of treatment failure in distinct infection settings, for example in the lungs of cystic fibrosis patients. Here, we discover that cell envelope protein homeostasis pathways underpin both antibiotic resistance and cross-protection in CF-associated bacteria. We find that inhibition of oxidative protein folding inactivates multiple species-specific resistance proteins. Using this strategy, we sensitize multi-drug resistant Pseudomonas aeruginosa to β-lactam antibiotics and demonstrate promise of new treatment avenues for the recalcitrant pathogen Stenotrophomonas maltophilia. The same approach also inhibits cross-protection between resistant S. maltophilia and susceptible P. aeruginosa, allowing eradication of both commonly co-occurring CF-associated organisms. Our results provide the basis for the development of next-generation strategies that target antibiotic resistance, while also impairing specific interbacterial interactions that enhance the severity of polymicrobial infections.
Collapse
Affiliation(s)
- Nikol Kadeřábková
- Department of Molecular Biosciences, The University of Texas at Austin, Austin, 78712, Texas, USA
- Centre for Bacterial Resistance Biology, Department of Life Sciences, Imperial College London, London, SW7 2AZ, UK
| | - R. Christopher D. Furniss
- Centre for Bacterial Resistance Biology, Department of Life Sciences, Imperial College London, London, SW7 2AZ, UK
| | - Evgenia Maslova
- Division of Biosciences, Department of Life Sciences, College of Health and Life Sciences, Brunel University London, Uxbridge, UB8 3PH, UK
| | - Lara Eisaiankhongi
- Division of Biosciences, Department of Life Sciences, College of Health and Life Sciences, Brunel University London, Uxbridge, UB8 3PH, UK
| | - Patricia Bernal
- Departamento de Microbiología, Facultad de Biología, Universidad de Sevilla, Seville, 41012, Spain
| | - Alain Filloux
- Centre for Bacterial Resistance Biology, Department of Life Sciences, Imperial College London, London, SW7 2AZ, UK
- Singapore Centre for Environmental Life Sciences Engineering, Nanyang Technological University, 637551, Singapore
| | - Cristina Landeta
- Department of Biology, Indiana University, Bloomington, Indiana, 47405, USA
| | - Diego Gonzalez
- Laboratoire de Microbiologie, Institut de Biologie, Université de Neuchâtel, Neuchâtel, 2000, Switzerland
| | - Ronan R. McCarthy
- Division of Biosciences, Department of Life Sciences, College of Health and Life Sciences, Brunel University London, Uxbridge, UB8 3PH, UK
| | - Despoina A.I. Mavridou
- Department of Molecular Biosciences, The University of Texas at Austin, Austin, 78712, Texas, USA
- John Ring LaMontagne Center for Infectious Diseases, The University of Texas at Austin, Austin, 78712, Texas, USA
| |
Collapse
|
3
|
Kadeřábková N, Mahmood AJS, Furniss RCD, Mavridou DAI. Making a chink in their armor: Current and next-generation antimicrobial strategies against the bacterial cell envelope. Adv Microb Physiol 2023; 83:221-307. [PMID: 37507160 PMCID: PMC10517717 DOI: 10.1016/bs.ampbs.2023.05.003] [Citation(s) in RCA: 1] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 07/30/2023]
Abstract
Gram-negative bacteria are uniquely equipped to defeat antibiotics. Their outermost layer, the cell envelope, is a natural permeability barrier that contains an array of resistance proteins capable of neutralizing most existing antimicrobials. As a result, its presence creates a major obstacle for the treatment of resistant infections and for the development of new antibiotics. Despite this seemingly impenetrable armor, in-depth understanding of the cell envelope, including structural, functional and systems biology insights, has promoted efforts to target it that can ultimately lead to the generation of new antibacterial therapies. In this article, we broadly overview the biology of the cell envelope and highlight attempts and successes in generating inhibitors that impair its function or biogenesis. We argue that the very structure that has hampered antibiotic discovery for decades has untapped potential for the design of novel next-generation therapeutics against bacterial pathogens.
Collapse
Affiliation(s)
- Nikol Kadeřábková
- Department of Molecular Biosciences, The University of Texas at Austin, Austin, TX, United States
| | - Ayesha J S Mahmood
- Department of Molecular Biosciences, The University of Texas at Austin, Austin, TX, United States
| | - R Christopher D Furniss
- MRC Centre for Molecular Bacteriology and Infection, Department of Life Sciences, Imperial College London, London, United Kingdom
| | - Despoina A I Mavridou
- Department of Molecular Biosciences, The University of Texas at Austin, Austin, TX, United States; John Ring LaMontagne Center for Infectious Diseases, The University of Texas at Austin, Austin, TX, United States.
| |
Collapse
|
4
|
Randall JR, Wang X, Groover KE, O'Donnell AC, Davies BW. Using display technologies to identify macrocyclic peptide antibiotics. BIOCHIMICA ET BIOPHYSICA ACTA. MOLECULAR CELL RESEARCH 2023; 1870:119473. [PMID: 37011732 PMCID: PMC10198949 DOI: 10.1016/j.bbamcr.2023.119473] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 03/31/2022] [Revised: 02/09/2023] [Accepted: 02/19/2023] [Indexed: 04/03/2023]
Abstract
Antibiotic resistant bacterial infections are now a leading cause of global mortality. While drug resistance continues to spread, the clinical antibiotic pipeline has become bare. This discord has focused attention on developing new strategies for antimicrobial discovery. Natural macrocyclic peptide-based products have provided novel antibiotics and antibiotic scaffolds targeting several essential bacterial cell envelope processes, but discovery of such natural products remains a slow and inefficient process. Synthetic strategies employing peptide display technologies can quickly screen large libraries of macrocyclic sequences for specific target binding and general antibacterial potential providing alternative approaches for new antibiotic discovery. Here we review cell envelope processes that can be targeted with macrocyclic peptide therapeutics, outline important macrocyclic peptide display technologies, and discuss future strategies for both library design and screening.
Collapse
Affiliation(s)
- Justin R Randall
- University of Texas at Austin, Department of Molecular Biosciences, Austin, TX, USA.
| | - Xun Wang
- University of Texas at Austin, Department of Molecular Biosciences, Austin, TX, USA
| | - Kyra E Groover
- University of Texas at Austin, Department of Molecular Biosciences, Austin, TX, USA
| | - Angela C O'Donnell
- University of Texas at Austin, Department of Molecular Biosciences, Austin, TX, USA
| | - Bryan W Davies
- University of Texas at Austin, Department of Molecular Biosciences, Austin, TX, USA.
| |
Collapse
|
5
|
Whitehouse RL, Alwan WS, Ilyichova OV, Taylor AJ, Chandrashekaran IR, Mohanty B, Doak BC, Scanlon MJ. Fragment screening libraries for the identification of protein hot spots and their minimal binding pharmacophores. RSC Med Chem 2023; 14:135-143. [PMID: 36760747 PMCID: PMC9890547 DOI: 10.1039/d2md00253a] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/30/2022] [Accepted: 11/11/2022] [Indexed: 11/30/2022] Open
Abstract
Fragment-based drug design relies heavily on structural information for the elaboration and optimisation of hits. The ability to identify neighbouring binding hot spots, energetically favourable interactions and conserved binding motifs in protein structures through X-ray crystallography can inform the evolution of fragments into lead-like compounds through structure-based design. The composition of fragment libraries can be designed and curated to fit this purpose and herein, we describe and compare screening libraries containing compounds comprising between 2 and 18 heavy atoms. We evaluate the properties of the compounds in these libraries and assess their ability to probe protein surfaces for binding hot spots.
Collapse
Affiliation(s)
- Rebecca L Whitehouse
- Medicinal Chemistry, Monash Institute of Pharmaceutical Sciences, Monash University Parkville VIC 3052 Australia
| | - Wesam S Alwan
- Medicinal Chemistry, Monash Institute of Pharmaceutical Sciences, Monash University Parkville VIC 3052 Australia
| | - Olga V Ilyichova
- Medicinal Chemistry, Monash Institute of Pharmaceutical Sciences, Monash University Parkville VIC 3052 Australia
- Australian Synchrotron, ANSTO Clayton VIC 3168 Australia
- ARC Training Centre for Fragment Based Design, Monash Institute of Pharmaceutical Sciences, Monash University Parkville VIC 3052 Australia
| | - Ashley J Taylor
- Medicinal Chemistry, Monash Institute of Pharmaceutical Sciences, Monash University Parkville VIC 3052 Australia
| | - Indu R Chandrashekaran
- Medicinal Chemistry, Monash Institute of Pharmaceutical Sciences, Monash University Parkville VIC 3052 Australia
- ARC Training Centre for Fragment Based Design, Monash Institute of Pharmaceutical Sciences, Monash University Parkville VIC 3052 Australia
- Monash Fragment Platform, Monash Institute of Pharmaceutical Sciences, Monash University Parkville VIC 3052 Australia
| | - Biswaranjan Mohanty
- Medicinal Chemistry, Monash Institute of Pharmaceutical Sciences, Monash University Parkville VIC 3052 Australia
| | - Bradley C Doak
- Medicinal Chemistry, Monash Institute of Pharmaceutical Sciences, Monash University Parkville VIC 3052 Australia
- ARC Training Centre for Fragment Based Design, Monash Institute of Pharmaceutical Sciences, Monash University Parkville VIC 3052 Australia
- Monash Fragment Platform, Monash Institute of Pharmaceutical Sciences, Monash University Parkville VIC 3052 Australia
| | - Martin J Scanlon
- Medicinal Chemistry, Monash Institute of Pharmaceutical Sciences, Monash University Parkville VIC 3052 Australia
- ARC Training Centre for Fragment Based Design, Monash Institute of Pharmaceutical Sciences, Monash University Parkville VIC 3052 Australia
- Monash Fragment Platform, Monash Institute of Pharmaceutical Sciences, Monash University Parkville VIC 3052 Australia
| |
Collapse
|
6
|
Chaudhuri D, Banerjee S, Chakraborty S, Chowdhury D, Haldar S. Direct Observation of the Mechanical Role of Bacterial Chaperones in Protein Folding. Biomacromolecules 2022; 23:2951-2967. [PMID: 35678300 DOI: 10.1021/acs.biomac.2c00451] [Citation(s) in RCA: 5] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
Abstract
Protein folding under force is an integral source of generating mechanical energy in various cellular processes, ranging from protein translation to degradation. Although chaperones are well known to interact with proteins under mechanical force, how they respond to force and control cellular energetics remains unknown. To address this question, we introduce a real-time magnetic tweezer technology herein to mimic the physiological force environment on client proteins, keeping the chaperones unperturbed. We studied two structurally distinct client proteins--protein L and talin with seven different chaperones─independently and in combination and proposed a novel mechanical activity of chaperones. We found that chaperones behave differently, while these client proteins are under force, than their previously known functions. For instance, tunnel-associated chaperones (DsbA and trigger factor), otherwise working as holdase without force, assist folding under force. This process generates an additional mechanical energy up to ∼147 zJ to facilitate translation or translocation. However, well-known cytoplasmic foldase chaperones (PDI, thioredoxin, or DnaKJE) do not possess the mechanical folding ability under force. Notably, the transferring chaperones (DnaK, DnaJ, and SecB) act as holdase and slow down the folding process, both in the presence and absence of force, to prevent misfolding of the client proteins. This provides an emerging insight of mechanical roles of chaperones: they can generate or consume energy by shifting the energy landscape of the client proteins toward a folded or an unfolded state, suggesting an evolutionary mechanism to minimize energy consumption in various biological processes.
Collapse
Affiliation(s)
- Deep Chaudhuri
- Department of Biological Sciences, Ashoka University, Sonepat, Haryana 131029, India
| | - Souradeep Banerjee
- Department of Biological Sciences, Ashoka University, Sonepat, Haryana 131029, India
| | - Soham Chakraborty
- Department of Biological Sciences, Ashoka University, Sonepat, Haryana 131029, India
| | - Debojyoti Chowdhury
- Department of Biological Sciences, Ashoka University, Sonepat, Haryana 131029, India
| | - Shubhasis Haldar
- Department of Biological Sciences, Ashoka University, Sonepat, Haryana 131029, India
| |
Collapse
|
7
|
Petit GA, Hong Y, Djoko KY, Whitten AE, Furlong EJ, McCoy AJ, Gulbis JM, Totsika M, Martin JL, Halili MA. The suppressor of copper sensitivity protein C from Caulobacter crescentus is a trimeric disulfide isomerase that binds copper(I) with subpicomolar affinity. ACTA CRYSTALLOGRAPHICA SECTION D STRUCTURAL BIOLOGY 2022; 78:337-352. [PMID: 35234148 PMCID: PMC8900818 DOI: 10.1107/s2059798322000729] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 07/26/2021] [Accepted: 01/21/2022] [Indexed: 11/10/2022]
Abstract
The characterization of the suppressor of copper sensitivity protein C from C. crescentus is reported. The introduction of disulfide bonds into periplasmic proteins is a critical process in many Gram-negative bacteria. The formation and regulation of protein disulfide bonds have been linked to the production of virulence factors. Understanding the different pathways involved in this process is important in the development of strategies to disarm pathogenic bacteria. The well characterized disulfide bond-forming (DSB) proteins play a key role by introducing or isomerizing disulfide bonds between cysteines in substrate proteins. Curiously, the suppressor of copper sensitivity C proteins (ScsCs), which are part of the bacterial copper-resistance response, share structural and functional similarities with DSB oxidase and isomerase proteins, including the presence of a catalytic thioredoxin domain. However, the oxidoreductase activity of ScsC varies with its oligomerization state, which depends on a poorly conserved N-terminal domain. Here, the structure and function of Caulobacter crescentus ScsC (CcScsC) have been characterized. It is shown that CcScsC binds copper in the copper(I) form with subpicomolar affinity and that its isomerase activity is comparable to that of Escherichia coli DsbC, the prototypical dimeric bacterial isomerase. It is also reported that CcScsC functionally complements trimeric Proteus mirabilis ScsC (PmScsC) in vivo, enabling the swarming of P. mirabilis in the presence of copper. Using mass photometry and small-angle X-ray scattering (SAXS) the protein is demonstrated to be trimeric in solution, like PmScsC, and not dimeric like EcDsbC. The crystal structure of CcScsC was also determined at a resolution of 2.6 Å, confirming the trimeric state and indicating that the trimerization results from interactions between the N-terminal α-helical domains of three CcScsC protomers. The SAXS data analysis suggested that the protomers are dynamic, like those of PmScsC, and are able to sample different conformations in solution.
Collapse
|
8
|
Furniss RCD, Kaderabkova N, Barker D, Bernal P, Maslova E, Antwi AA, McNeil HE, Pugh HL, Dortet L, Blair JM, Larrouy-Maumus GJ, McCarthy RR, Gonzalez D, Mavridou DA. Breaking antimicrobial resistance by disrupting extracytoplasmic protein folding. eLife 2022; 11:57974. [PMID: 35025730 PMCID: PMC8863373 DOI: 10.7554/elife.57974] [Citation(s) in RCA: 4] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/19/2020] [Accepted: 01/11/2022] [Indexed: 11/24/2022] Open
Abstract
Antimicrobial resistance in Gram-negative bacteria is one of the greatest threats to global health. New antibacterial strategies are urgently needed, and the development of antibiotic adjuvants that either neutralize resistance proteins or compromise the integrity of the cell envelope is of ever-growing interest. Most available adjuvants are only effective against specific resistance proteins. Here, we demonstrate that disruption of cell envelope protein homeostasis simultaneously compromises several classes of resistance determinants. In particular, we find that impairing DsbA-mediated disulfide bond formation incapacitates diverse β-lactamases and destabilizes mobile colistin resistance enzymes. Furthermore, we show that chemical inhibition of DsbA sensitizes multidrug-resistant clinical isolates to existing antibiotics and that the absence of DsbA, in combination with antibiotic treatment, substantially increases the survival of Galleria mellonella larvae infected with multidrug-resistant Pseudomonas aeruginosa. This work lays the foundation for the development of novel antibiotic adjuvants that function as broad-acting resistance breakers. Antibiotics, like penicillin, are the foundation of modern medicine, but bacteria are evolving to resist their effects. Some of the most harmful pathogens belong to a group called the 'Gram-negative bacteria', which have an outer layer – called the cell envelope – that acts as a drug barrier. This envelope contains antibiotic resistance proteins that can deactivate or repel antibiotics or even pump them out of the cell once they get in. One way to tackle antibiotic resistance could be to stop these proteins from working. Proteins are long chains of building blocks called amino acids that fold into specific shapes. In order for a protein to perform its role correctly, it must fold in the right way. In bacteria, a protein called DsbA helps other proteins fold correctly by holding them in place and inserting links called disulfide bonds. It was unclear whether DsbA plays a role in the folding of antibiotic resistance proteins, but if it did, it might open up new ways to treat antibiotic resistant infections. To find out more, Furniss, Kaderabkova et al. collected the genes that code for several antibiotic resistance proteins and put them into Escherichia coli bacteria, which made the bacteria resistant to antibiotics. Furniss, Kaderabkova et al. then stopped the modified E. coli from making DsbA, which led to the antibiotic resistance proteins becoming unstable and breaking down because they could not fold correctly. Further experiments showed that blocking DsbA with a chemical inhibitor in other pathogenic species of Gram-negative bacteria made these bacteria more sensitive to antibiotics that they would normally resist. To demonstrate that using this approach could work to stop infections by these bacteria, Furniss, Kaderabkova et al. used Gram-negative bacteria that produced antibiotic resistance proteins but could not make DsbA to infect insect larvae. The larvae were then treated with antibiotics, which increased their survival rate, indicating that blocking DsbA may be a good approach to tackling antibiotic resistant bacteria. According to the World Health Organization, developing new treatments against Gram-negative bacteria is of critical importance, but the discovery of new drugs has ground to a halt. One way around this is to develop ways to make existing drugs work better. Making drugs that block DsbA could offer a way to treat resistant infections using existing antibiotics in the future.
Collapse
Affiliation(s)
| | - Nikol Kaderabkova
- Department of Molecular Biosciences, The University of Texas at Austin, Austin, United States
| | - Declan Barker
- Department of Life Sciences, Imperial College London, London, United Kingdom
| | - Patricia Bernal
- Department of Microbiology, Universidad de Sevilla, Seville, Spain
| | - Evgenia Maslova
- Department of Life Sciences, Brunel University London, London, United Kingdom
| | - Amanda Aa Antwi
- Department of Life Sciences, Imperial College London, London, United Kingdom
| | - Helen E McNeil
- Institute of Microbiology and Infection, University of Birmingham, Birmingham, United Kingdom
| | - Hannah L Pugh
- Institute of Microbiology and Infection, University of Birmingham, Birmingham, United Kingdom
| | - Laurent Dortet
- Department of Bacteriology-Hygiene, Paris-Sud University, Paris, France
| | - Jessica Ma Blair
- Institute of Microbiology and Infection, University of Birmingham, Birmingham, United Kingdom
| | | | - Ronan R McCarthy
- Department of Life Sciences, Brunel University London, London, United Kingdom
| | - Diego Gonzalez
- Department of Biology, University of Neuchatel, Neuchatel, Switzerland
| | - Despoina Ai Mavridou
- Department of Molecular Biosciences, The University of Texas at Austin, Austin, United States
| |
Collapse
|
9
|
Wang G, Mohanty B, Williams ML, Doak BC, Dhouib R, Totsika M, McMahon R, Sharma G, Zheng D, Bentley MR, Chin YKY, Horne J, Chalmers DK, Heras B, Scanlon MJ. Selective binding of small molecules to Vibrio cholerae DsbA offers a starting point for the design of novel antibacterials. ChemMedChem 2022; 17:e202100673. [PMID: 34978144 PMCID: PMC9305425 DOI: 10.1002/cmdc.202100673] [Citation(s) in RCA: 2] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/29/2021] [Revised: 12/23/2021] [Indexed: 11/25/2022]
Abstract
DsbA enzymes catalyze oxidative folding of proteins that are secreted into the periplasm of Gram‐negative bacteria, and they are indispensable for the virulence of human pathogens such as Vibrio cholerae and Escherichia coli. Therefore, targeting DsbA represents an attractive approach to control bacterial virulence. X‐ray crystal structures reveal that DsbA enzymes share a similar fold, however, the hydrophobic groove adjacent to the active site, which is implicated in substrate binding, is shorter and flatter in the structure of V. cholerae DsbA (VcDsbA) compared to E. coli DsbA (EcDsbA). The flat and largely featureless nature of this hydrophobic groove is challenging for the development of small molecule inhibitors. Using fragment‐based screening approaches, we have identified a novel small molecule, based on the benzimidazole scaffold, that binds to the hydrophobic groove of oxidized VcDsbA with a KD of 446±10 μM. The same benzimidazole compound has ∼8‐fold selectivity for VcDsbA over EcDsbA and binds to oxidized EcDsbA, with KD>3.5 mM. We generated a model of the benzimidazole complex with VcDsbA using NMR data but were unable to determine the structure of the benzimidazole bound EcDsbA using either NMR or X‐ray crystallography. Therefore, a structural basis for the observed selectivity is unclear. To better understand ligand binding to these two enzymes we crystallized each of them in complex with a known ligand, the bile salt sodium taurocholate. The crystal structures show that taurocholate adopts different binding poses in complex with VcDsbA and EcDsbA, and reveal the protein‐ligand interactions that stabilize the different modes of binding. This work highlights the capacity of fragment‐based drug discovery to identify inhibitors of challenging protein targets. In addition, it provides a starting point for development of more potent and specific VcDsbA inhibitors that act through a novel anti‐virulence mechanism.
Collapse
Affiliation(s)
- Geqing Wang
- La Trobe University - Bundoora Campus: La Trobe University, Department of Biochemistry and Genetics, AUSTRALIA
| | | | - Martin L Williams
- Monash Institute of Pharmaceutical Sciences, Medicinal Chemistry, AUSTRALIA
| | - Bradley C Doak
- Monash Institute of Pharmaceutical Sciences, Medicinal Chemistry, AUSTRALIA
| | - Rabeb Dhouib
- Queensland University of Technology, School of Biomedical Sciences, AUSTRALIA
| | - Makrina Totsika
- Queensland University of Technology, School of Biomedical Sciences, AUSTRALIA
| | - Roisin McMahon
- Griffith University, Griffith Institute for Drug Discovery, AUSTRALIA
| | - Gaurav Sharma
- Monash Institute of Pharmaceutical Sciences, Medicinal Chemistry, AUSTRALIA
| | - Dan Zheng
- Monash Institute of Pharmaceutical Sciences, Medicinal Chemistry, AUSTRALIA
| | - Matthew R Bentley
- Monash Institute of Pharmaceutical Sciences, Medicinal Chemistry, AUSTRALIA
| | - Yanni Ka-Yan Chin
- The University of Queensland, Cantre for Advanced Imaging, AUSTRALIA
| | - James Horne
- University of Tasmania, Central Science Laboratory, AUSTRALIA
| | - David K Chalmers
- Monash Institute of Pharmaceutical Sciences, Medicinal Chemistry, AUSTRALIA
| | - Begoña Heras
- La Trobe University, Department of Biochemistry and Genetics, AUSTRALIA
| | - Martin Joseph Scanlon
- Monash Institute of Pharmaceutical Sciences Monash University Parkville Campus, Medicinal Chemistry, 381 Royal Parade, Monash University, 3052, Parkville, AUSTRALIA
| |
Collapse
|
10
|
Petit GA, Mohanty B, McMahon RM, Nebl S, Hilko DH, Wilde KL, Scanlon MJ, Martin JL, Halili MA. Identification and characterization of two drug-like fragments that bind to the same cryptic binding pocket of Burkholderia pseudomallei DsbA. Acta Crystallogr D Struct Biol 2022; 78:75-90. [PMID: 34981764 PMCID: PMC8725163 DOI: 10.1107/s2059798321011475] [Citation(s) in RCA: 2] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/21/2021] [Accepted: 10/29/2021] [Indexed: 01/10/2023] Open
Abstract
Disulfide-bond-forming proteins (Dsbs) play a crucial role in the pathogenicity of many Gram-negative bacteria. Disulfide-bond-forming protein A (DsbA) catalyzes the formation of the disulfide bonds necessary for the activity and stability of multiple substrate proteins, including many virulence factors. Hence, DsbA is an attractive target for the development of new drugs to combat bacterial infections. Here, two fragments, bromophenoxy propanamide (1) and 4-methoxy-N-phenylbenzenesulfonamide (2), were identified that bind to DsbA from the pathogenic bacterium Burkholderia pseudomallei, the causative agent of melioidosis. The crystal structures of oxidized B. pseudomallei DsbA (termed BpsDsbA) co-crystallized with 1 or 2 show that both fragments bind to a hydrophobic pocket that is formed by a change in the side-chain orientation of Tyr110. This conformational change opens a `cryptic' pocket that is not evident in the apoprotein structure. This binding location was supported by 2D-NMR studies, which identified a chemical shift perturbation of the Tyr110 backbone amide resonance of more than 0.05 p.p.m. upon the addition of 2 mM fragment 1 and of more than 0.04 p.p.m. upon the addition of 1 mM fragment 2. Although binding was detected by both X-ray crystallography and NMR, the binding affinity (Kd) for both fragments was low (above 2 mM), suggesting weak interactions with BpsDsbA. This conclusion is also supported by the crystal structure models, which ascribe partial occupancy to the ligands in the cryptic binding pocket. Small fragments such as 1 and 2 are not expected to have a high energetic binding affinity due to their relatively small surface area and the few functional groups that are available for intermolecular interactions. However, their simplicity makes them ideal for functionalization and optimization. The identification of the binding sites of 1 and 2 to BpsDsbA could provide a starting point for the development of more potent novel antimicrobial compounds that target DsbA and bacterial virulence.
Collapse
Affiliation(s)
- Guillaume A. Petit
- Griffith Institute for Drug Discovery, Griffith University, Building N75, 46 Don Young Road, Nathan, QLD 4111, Australia
| | - Biswaranjan Mohanty
- Medicinal Chemistry, Monash Institute of Pharmaceutical Sciences, Monash University, 381 Royal Parade, Parkville, VIC 3052, Australia
- ARC Centre for Fragment-Based Design, Monash Institute of Pharmaceutical Sciences, Monash University, 381 Royal Parade, Parkville, VIC 3052, Australia
- Sydney Analytical Core Research Facility, The University of Sydney, Sydney, NSW 2006, Australia
| | - Róisín M. McMahon
- Griffith Institute for Drug Discovery, Griffith University, Building N75, 46 Don Young Road, Nathan, QLD 4111, Australia
| | - Stefan Nebl
- Medicinal Chemistry, Monash Institute of Pharmaceutical Sciences, Monash University, 381 Royal Parade, Parkville, VIC 3052, Australia
| | - David H. Hilko
- Griffith Institute for Drug Discovery, Griffith University, Building N75, 46 Don Young Road, Nathan, QLD 4111, Australia
| | - Karyn L. Wilde
- National Deuteration Facility, Australian Nuclear Science and Technology Organization (ANSTO), New Illawarra Road, Lucas Heights, NSW 2234, Australia
| | - Martin J. Scanlon
- Medicinal Chemistry, Monash Institute of Pharmaceutical Sciences, Monash University, 381 Royal Parade, Parkville, VIC 3052, Australia
- ARC Centre for Fragment-Based Design, Monash Institute of Pharmaceutical Sciences, Monash University, 381 Royal Parade, Parkville, VIC 3052, Australia
| | - Jennifer L. Martin
- Griffith Institute for Drug Discovery, Griffith University, Building N75, 46 Don Young Road, Nathan, QLD 4111, Australia
- Vice-Chancellor’s Unit, University of Wollongong, Building 36, Wollongong, NSW 2522, Australia
| | - Maria A. Halili
- Griffith Institute for Drug Discovery, Griffith University, Building N75, 46 Don Young Road, Nathan, QLD 4111, Australia
| |
Collapse
|
11
|
Interplay between DsbA1, DsbA2 and C8J_1298 Periplasmic Oxidoreductases of Campylobacter jejuni and Their Impact on Bacterial Physiology and Pathogenesis. Int J Mol Sci 2021; 22:ijms222413451. [PMID: 34948248 PMCID: PMC8708908 DOI: 10.3390/ijms222413451] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/28/2021] [Revised: 12/08/2021] [Accepted: 12/10/2021] [Indexed: 01/13/2023] Open
Abstract
The bacterial proteins of the Dsb family catalyze the formation of disulfide bridges between cysteine residues that stabilize protein structures and ensure their proper functioning. Here, we report the detailed analysis of the Dsb pathway of Campylobacter jejuni. The oxidizing Dsb system of this pathogen is unique because it consists of two monomeric DsbAs (DsbA1 and DsbA2) and one dimeric bifunctional protein (C8J_1298). Previously, we showed that DsbA1 and C8J_1298 are redundant. Here, we unraveled the interaction between the two monomeric DsbAs by in vitro and in vivo experiments and by solving their structures and found that both monomeric DsbAs are dispensable proteins. Their structures confirmed that they are homologs of EcDsbL. The slight differences seen in the surface charge of the proteins do not affect the interaction with their redox partner. Comparative proteomics showed that several respiratory proteins, as well as periplasmic transport proteins, are targets of the Dsb system. Some of these, both donors and electron acceptors, are essential elements of the C. jejuni respiratory process under oxygen-limiting conditions in the host intestine. The data presented provide detailed information on the function of the C. jejuni Dsb system, identifying it as a potential target for novel antibacterial molecules.
Collapse
|
12
|
Shchelik IS, Gademann K. Thiol- and Disulfide-Containing Vancomycin Derivatives Against Bacterial Resistance and Biofilm Formation. ACS Med Chem Lett 2021; 12:1898-1904. [PMID: 34917252 DOI: 10.1021/acsmedchemlett.1c00455] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/25/2021] [Accepted: 10/14/2021] [Indexed: 12/28/2022] Open
Abstract
Antibiotic-resistant and biofilm-associated infections constitute a rapidly growing issue. Use of the last-resort antibiotic vancomycin is under threat due to the increasing appearance of vancomycin-resistant bacteria as well as the formation of biofilms. Herein, we report a series of novel vancomycin derivatives carrying thiol- and disulfide-containing moieties. The new compounds exhibited enhanced antibacterial activity against a broad range of bacterial strains, including vancomycin-resistant microbes and Gram-negative bacteria. Moreover, all obtained derivatives demonstrated improved antibiofilm formation activity against VanB-resistant Enterococcus compared to vancomycin. This work establishes a promising strategy for combating drug-resistant bacterial infections or disrupting biofilm formation and advances the knowledge on the structural optimization of antibiotics with sulfur-containing modifications.
Collapse
Affiliation(s)
- Inga S. Shchelik
- Department of Chemistry, University of Zurich, Winterthurerstrasse 190, 8057 Zurich, Switzerland
| | - Karl Gademann
- Department of Chemistry, University of Zurich, Winterthurerstrasse 190, 8057 Zurich, Switzerland
| |
Collapse
|
13
|
Santos-Martin C, Wang G, Subedi P, Hor L, Totsika M, Paxman JJ, Heras B. Structural bioinformatic analysis of DsbA proteins and their pathogenicity associated substrates. Comput Struct Biotechnol J 2021; 19:4725-4737. [PMID: 34504665 PMCID: PMC8405906 DOI: 10.1016/j.csbj.2021.08.018] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/17/2021] [Revised: 08/12/2021] [Accepted: 08/12/2021] [Indexed: 01/02/2023] Open
Abstract
The disulfide bond (DSB) forming system and in particular DsbA, is a key bacterial oxidative folding catalyst. Due to its role in promoting the correct assembly of a wide range of virulence factors required at different stages of the infection process, DsbA is a master virulence rheostat, making it an attractive target for the development of new virulence blockers. Although DSB systems have been extensively studied across different bacterial species, to date, little is known about how DsbA oxidoreductases are able to recognize and interact with such a wide range of substrates. This review summarizes the current knowledge on the DsbA enzymes, with special attention on their interaction with the partner oxidase DsbB and substrates associated with bacterial virulence. The structurally and functionally diverse set of bacterial proteins that rely on DsbA-mediated disulfide bond formation are summarized. Local sequence and secondary structure elements of these substrates are analyzed to identify common elements recognized by DsbA enzymes. This not only provides information on protein folding systems in bacteria but also offers tools for identifying new DsbA substrates and informs current efforts aimed at developing DsbA targeted anti-microbials.
Collapse
Affiliation(s)
- Carlos Santos-Martin
- Department of Biochemistry and Genetics, La Trobe Institute of Molecular Science, La Trobe University, Melbourne, Australia
| | - Geqing Wang
- Department of Biochemistry and Genetics, La Trobe Institute of Molecular Science, La Trobe University, Melbourne, Australia
| | - Pramod Subedi
- Department of Biochemistry and Genetics, La Trobe Institute of Molecular Science, La Trobe University, Melbourne, Australia
| | - Lilian Hor
- Department of Biochemistry and Genetics, La Trobe Institute of Molecular Science, La Trobe University, Melbourne, Australia
| | - Makrina Totsika
- Centre for Immunology and Infection Control, School of Biomedical Sciences, Queensland University of Technology, Brisbane, Australia
| | - Jason John Paxman
- Department of Biochemistry and Genetics, La Trobe Institute of Molecular Science, La Trobe University, Melbourne, Australia
| | - Begoña Heras
- Department of Biochemistry and Genetics, La Trobe Institute of Molecular Science, La Trobe University, Melbourne, Australia
| |
Collapse
|
14
|
Eckels EC, Chaudhuri D, Chakraborty S, Echelman DJ, Haldar S. DsbA is a redox-switchable mechanical chaperone. Chem Sci 2021; 12:11109-11120. [PMID: 34522308 PMCID: PMC8386657 DOI: 10.1039/d1sc03048e] [Citation(s) in RCA: 7] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/06/2021] [Accepted: 07/17/2021] [Indexed: 12/18/2022] Open
Abstract
DsbA is a ubiquitous bacterial oxidoreductase that associates with substrates during and after translocation, yet its involvement in protein folding and translocation remains an open question. Here we demonstrate a redox-controlled chaperone activity of DsbA, on both cysteine-containing and cysteine-free substrates, using magnetic tweezers-based single molecule force spectroscopy that enables independent measurements of oxidoreductase activity and chaperone behavior. Interestingly we found that this chaperone activity is tuned by the oxidation state of DsbA; oxidized DsbA is a strong promoter of folding, but the effect is weakened by the reduction of the catalytic CXXC motif. We further localize the chaperone binding site of DsbA using a seven-residue peptide which effectively blocks the chaperone activity. We found that the DsbA assisted folding of proteins in the periplasm generates enough mechanical work to decrease the ATP consumption needed for periplasmic translocation by up to 33%.
Collapse
Affiliation(s)
- Edward C Eckels
- Department of Biological Sciences, Columbia University New York NY 10027 USA
- Department of Internal Medicine, Columbia University Medical Center New York NY 10032 USA
| | - Deep Chaudhuri
- Department of Biological Sciences, Ashoka University Sonepat Haryana 131029 India
| | - Soham Chakraborty
- Department of Biological Sciences, Ashoka University Sonepat Haryana 131029 India
| | - Daniel J Echelman
- Department of Biological Sciences, Columbia University New York NY 10027 USA
| | - Shubhasis Haldar
- Department of Biological Sciences, Ashoka University Sonepat Haryana 131029 India
| |
Collapse
|
15
|
Elaboration of a benzofuran scaffold and evaluation of binding affinity and inhibition of Escherichia coli DsbA: A fragment-based drug design approach to novel antivirulence compounds. Bioorg Med Chem 2021; 45:116315. [PMID: 34364222 DOI: 10.1016/j.bmc.2021.116315] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/20/2021] [Revised: 07/15/2021] [Accepted: 07/16/2021] [Indexed: 11/20/2022]
Abstract
Bacterial thiol-disulfide oxidoreductase DsbA is essential for bacterial virulence factor assembly and has been identified as a viable antivirulence target. Herein, we report a structure-based elaboration of a benzofuran hit that bound to the active site groove of Escherichia coli DsbA. Substituted phenyl groups were installed at the 5- and 6-position of the benzofuran using Suzuki-Miyaura coupling. HSQC NMR titration experiments showed dissociation constants of this series in the high µM to low mM range and X-ray crystallography produced three co-structures, showing binding in the hydrophobic groove, comparable with that of the previously reported benzofurans. The 6-(m-methoxy)phenyl analogue (2b), which showed a promising binding pose, was chosen for elaboration from the C-2 position. The 2,6-disubstituted analogues bound to the hydrophobic region of the binding groove and the C-2 groups extended into the more polar, previously un-probed, region of the binding groove. Biochemical analysis of the 2,6-disubsituted analogues showed they inhibited DsbA oxidation activity in vitro. The results indicate the potential to develop the elaborated benzofuran series into a novel class of antivirulence compounds.
Collapse
|
16
|
Deciphering the role of sulfonamides and molecular basis of thioredoxin domain dynamics through comparative simulations. J Mol Liq 2021. [DOI: 10.1016/j.molliq.2020.114797] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/19/2022]
|
17
|
Pandeya A, Ojo I, Alegun O, Wei Y. Periplasmic Targets for the Development of Effective Antimicrobials against Gram-Negative Bacteria. ACS Infect Dis 2020; 6:2337-2354. [PMID: 32786281 PMCID: PMC8187054 DOI: 10.1021/acsinfecdis.0c00384] [Citation(s) in RCA: 21] [Impact Index Per Article: 5.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/14/2022]
Abstract
Antibiotic resistance has emerged as a serious threat to global public health in recent years. Lack of novel antimicrobials, especially new classes of compounds, further aggravates the situation. For Gram-negative bacteria, their double layered cell envelope and an array of efflux pumps act as formidable barriers for antimicrobials to penetrate. While cytoplasmic targets are hard to reach, proteins in the periplasm are clearly more accessible, as the drug only needs to breach the outer membrane. In this review, we summarized recent efforts on the validation and testing of periplasmic proteins as potential antimicrobial targets and the development of related inhibitors that either inhibit the growth of a bacterial pathogen or reduce its virulence during interaction with host cells. We conclude that the periplasm contains a promising pool of novel antimicrobial targets that should be scrutinized more closely for the development of effective treatment against multidrug-resistant Gram-negative bacteria.
Collapse
Affiliation(s)
- Ankit Pandeya
- Department of Chemistry, University of Kentucky, Lexington, Kentucky 40506, United States
| | - Isoiza Ojo
- Department of Chemistry, University of Kentucky, Lexington, Kentucky 40506, United States
| | - Olaniyi Alegun
- Department of Chemistry, University of Kentucky, Lexington, Kentucky 40506, United States
| | - Yinan Wei
- Department of Chemistry, University of Kentucky, Lexington, Kentucky 40506, United States
| |
Collapse
|
18
|
The Fragment-Based Development of a Benzofuran Hit as a New Class of Escherichia coli DsbA Inhibitors. Molecules 2019; 24:molecules24203756. [PMID: 31635355 PMCID: PMC6832960 DOI: 10.3390/molecules24203756] [Citation(s) in RCA: 16] [Impact Index Per Article: 3.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/09/2019] [Revised: 10/13/2019] [Accepted: 10/15/2019] [Indexed: 11/17/2022] Open
Abstract
A fragment-based drug discovery approach was taken to target the thiol-disulfide oxidoreductase enzyme DsbA from Escherichia coli (EcDsbA). This enzyme is critical for the correct folding of virulence factors in many pathogenic Gram-negative bacteria, and small molecule inhibitors can potentially be developed as anti-virulence compounds. Biophysical screening of a library of fragments identified several classes of fragments with affinity to EcDsbA. One hit with high mM affinity, 2-(6-bromobenzofuran-3-yl)acetic acid (6), was chemically elaborated at several positions around the scaffold. X-ray crystal structures of the elaborated analogues showed binding in the hydrophobic binding groove adjacent to the catalytic disulfide bond of EcDsbA. Binding affinity was calculated based on NMR studies and compounds 25 and 28 were identified as the highest affinity binders with dissociation constants (KD) of 326 ± 25 and 341 ± 57 µM respectively. This work suggests the potential to develop benzofuran fragments into a novel class of EcDsbA inhibitors.
Collapse
|
19
|
Banaś AM, Bocian-Ostrzycka KM, Jagusztyn-Krynicka EK. Engineering of the Dsb (disulfide bond) proteins - contribution towards understanding their mechanism of action and their applications in biotechnology and medicine. Crit Rev Microbiol 2019; 45:433-450. [PMID: 31190593 DOI: 10.1080/1040841x.2019.1622509] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/09/2023]
Abstract
The Dsb protein family in prokaryotes catalyzes the generation of disulfide bonds between thiol groups of cysteine residues in nascent proteins, ensuring their proper three-dimensional structure; these bonds are crucial for protein stability and function. The first Dsb protein, Escherichia coli DsbA, was described in 1991. Since then, many details of the bond-formation process have been described through microbiological, biochemical, biophysical and bioinformatics strategies. Research with the model microorganism E. coli and many other bacterial species revealed an enormous diversity of bond-formation mechanisms. Research using Dsb protein engineering has significantly helped to reveal details of the disulfide bond formation. The first part of this review presents the research that led to understanding the mechanism of action of DsbA proteins, which directly transfer their own disulfide into target proteins. The second part concentrates on the mechanism of electron transport through the cell cytoplasmic membrane. Third and lastly, the review discusses the contribution of this research towards new antibacterial agents.
Collapse
Affiliation(s)
- Anna Marta Banaś
- Department of Bacterial Genetics, Institute of Microbiology, Faculty of Biology, University of Warsaw , Miecznikowa 1 , Warsaw , Poland
| | - Katarzyna Marta Bocian-Ostrzycka
- Department of Bacterial Genetics, Institute of Microbiology, Faculty of Biology, University of Warsaw , Miecznikowa 1 , Warsaw , Poland
| | | |
Collapse
|
20
|
Approaches to the Structure-Based Design of Antivirulence Drugs: Therapeutics for the Post-Antibiotic Era. Molecules 2019; 24:molecules24030378. [PMID: 30678155 PMCID: PMC6384752 DOI: 10.3390/molecules24030378] [Citation(s) in RCA: 13] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/22/2018] [Revised: 01/14/2019] [Accepted: 01/18/2019] [Indexed: 01/02/2023] Open
Abstract
The alarming rise of multidrug-resistant bacterial strains, coupled with decades of stagnation in the field of antibiotic development, necessitates exploration of new therapeutic approaches to treat bacterial infections. Targeting bacterial virulence is an attractive alternative to traditional antibiotics in that this approach disarms pathogens that cause human diseases, without placing immediate selective pressure on the target bacterium or harming commensal species. The growing number of validated virulence protein targets for which structural information has been obtained, along with advances in computational power and screening algorithms, make the rational design of antivirulence drugs a promising avenue to explore. Here, we review the principles of structure-based drug design and the exciting opportunities this technique presents for antivirulence drug discovery.
Collapse
|
21
|
Kahler CM, Sarkar-Tyson M, Kibble EA, Stubbs KA, Vrielink A. Enzyme targets for drug design of new anti-virulence therapeutics. Curr Opin Struct Biol 2018; 53:140-150. [PMID: 30223251 DOI: 10.1016/j.sbi.2018.08.010] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/24/2018] [Revised: 08/30/2018] [Accepted: 08/30/2018] [Indexed: 12/19/2022]
Abstract
Society has benefitted greatly from the use of antibiotics. Unfortunately, the misuse of these valuable molecules has resulted in increased levels of antibiotic resistance, a major global and public health issue. This resistance and the reliance on a small number of biological targets for the development of antibiotics emphasizes the need for new targets. A critical aspect guiding the development of new antimicrobials through a rational structure-guided approach is to understand the molecular structures of specific biological targets of interest. Here we give an overview of the structures of bacterial virulence enzyme targets involved in protein folding, peptidoglycan biosynthesis and cell wall modification. These include enzymes of the thiol-disulphide oxidoreductase pathway (DSB enzymes), peptidyl-proly cis/trans isomerases (Mips), enzymes from the Mur pathway and enzymes involved in lipopolysaccharide modification (EptA and ArnT). We also present progress towards inhibitor design of these targets for the development of novel anti-virulence therapeutic agents.
Collapse
Affiliation(s)
- Charlene M Kahler
- Marshall Centre for Infectious Disease Research and Training, School of Biomedical Sciences, University of Western Australia, 35 Stirling Highway, Crawley, WA, 6009, Australia
| | - Mitali Sarkar-Tyson
- Marshall Centre for Infectious Disease Research and Training, School of Biomedical Sciences, University of Western Australia, 35 Stirling Highway, Crawley, WA, 6009, Australia
| | - Emily A Kibble
- Marshall Centre for Infectious Disease Research and Training, School of Biomedical Sciences, University of Western Australia, 35 Stirling Highway, Crawley, WA, 6009, Australia
| | - Keith A Stubbs
- School of Molecular Sciences, University of Western Australia, 35 Stirling Highway, Crawley, WA, 6009, Australia
| | - Alice Vrielink
- School of Molecular Sciences, University of Western Australia, 35 Stirling Highway, Crawley, WA, 6009, Australia; Marshall Centre for Infectious Disease Research and Training, School of Biomedical Sciences, University of Western Australia, 35 Stirling Highway, Crawley, WA, 6009, Australia.
| |
Collapse
|
22
|
Totsika M, Vagenas D, Paxman JJ, Wang G, Dhouib R, Sharma P, Martin JL, Scanlon MJ, Heras B. Inhibition of Diverse DsbA Enzymes in Multi-DsbA Encoding Pathogens. Antioxid Redox Signal 2018; 29:653-666. [PMID: 29237285 PMCID: PMC6067686 DOI: 10.1089/ars.2017.7104] [Citation(s) in RCA: 24] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 01/02/2023]
Abstract
AIMS DsbA catalyzes disulfide bond formation in secreted and outer membrane proteins in bacteria. In pathogens, DsbA is a major facilitator of virulence constituting a target for antivirulence antimicrobial development. However, many pathogens encode multiple and diverse DsbA enzymes for virulence factor folding during infection. The aim of this study was to determine whether our recently identified inhibitors of Escherichia coli K-12 DsbA can inhibit the diverse DsbA enzymes found in two important human pathogens and attenuate their virulence. RESULTS DsbA inhibitors from two chemical classes (phenylthiophene and phenoxyphenyl derivatives) inhibited the virulence of uropathogenic E. coli and Salmonella enterica serovar Typhimurium, encoding two and three diverse DsbA homologues, respectively. Inhibitors blocked the virulence of dsbA null mutants complemented with structurally diverse DsbL and SrgA, suggesting that they were not selective for prototypical DsbA. Structural characterization of DsbA-inhibitor complexes showed that compounds from each class bind in a similar region of the hydrophobic groove adjacent to the Cys30-Pro31-His32-Cys33 (CPHC) active site. Modeling of DsbL- and SrgA-inhibitor interactions showed that these accessory enzymes could accommodate the inhibitors in their different hydrophobic grooves, supporting our in vivo findings. Further, we identified highly conserved residues surrounding the active site for 20 diverse bacterial DsbA enzymes, which could be exploited in developing inhibitors with a broad spectrum of activity. Innovation and Conclusion: We have developed tools to analyze the specificity of DsbA inhibitors in bacterial pathogens encoding multiple DsbA enzymes. This work demonstrates that DsbA inhibitors can be developed to target diverse homologues found in bacteria. Antioxid. Redox Signal. 29, 653-666.
Collapse
Affiliation(s)
- Makrina Totsika
- 1 Institute of Health and Biomedical Innovation, School of Biomedical Sciences, Queensland University of Technology , Queensland, Australia
| | - Dimitrios Vagenas
- 1 Institute of Health and Biomedical Innovation, School of Biomedical Sciences, Queensland University of Technology , Queensland, Australia
| | - Jason J Paxman
- 2 Department of Biochemistry and Genetics, La Trobe Institute for Molecular Science, La Trobe University , Bundoora, Australia
| | - Geqing Wang
- 2 Department of Biochemistry and Genetics, La Trobe Institute for Molecular Science, La Trobe University , Bundoora, Australia
| | - Rabeb Dhouib
- 1 Institute of Health and Biomedical Innovation, School of Biomedical Sciences, Queensland University of Technology , Queensland, Australia
| | - Pooja Sharma
- 3 Medicinal Chemistry, Monash Institute of Pharmaceutical Sciences, Monash University , Parkville, Australia
| | - Jennifer L Martin
- 4 Institute for Molecular Bioscience, University of Queensland , Queensland, Australia
| | - Martin J Scanlon
- 3 Medicinal Chemistry, Monash Institute of Pharmaceutical Sciences, Monash University , Parkville, Australia
| | - Begoña Heras
- 2 Department of Biochemistry and Genetics, La Trobe Institute for Molecular Science, La Trobe University , Bundoora, Australia
| |
Collapse
|
23
|
Virulence of the Melioidosis Pathogen Burkholderia pseudomallei Requires the Oxidoreductase Membrane Protein DsbB. Infect Immun 2018; 86:IAI.00938-17. [PMID: 29440370 PMCID: PMC5913862 DOI: 10.1128/iai.00938-17] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/21/2017] [Accepted: 02/04/2018] [Indexed: 12/26/2022] Open
Abstract
The naturally antibiotic-resistant bacterium Burkholderia pseudomallei is the causative agent of melioidosis, a disease with stubbornly high mortality and a complex, protracted treatment regimen. The worldwide incidence of melioidosis is likely grossly underreported, though it is known to be highly endemic in northern Australia and Southeast Asia. Bacterial disulfide bond (DSB) proteins catalyze the oxidative folding and isomerization of disulfide bonds in substrate proteins. In the present study, we demonstrate that B. pseudomallei membrane protein disulfide bond protein B (BpsDsbB) forms a functional redox relay with the previously characterized virulence mediator B. pseudomallei disulfide bond protein A (BpsDsbA). Genomic analysis of diverse B. pseudomallei clinical isolates demonstrated that dsbB is a highly conserved core gene. Critically, we show that DsbB is required for virulence in B. pseudomallei. A panel of B. pseudomalleidsbB deletion strains (K96243, 576, MSHR2511, MSHR0305b, and MSHR5858) were phenotypically diverse according to the results of in vitro assays that assess hallmarks of virulence. Irrespective of their in vitro virulence phenotypes, two deletion strains were attenuated in a BALB/c mouse model of infection. A crystal structure of a DsbB-derived peptide complexed with BpsDsbA provides the first molecular characterization of their interaction. This work contributes to our broader understanding of DSB redox biology and will support the design of antimicrobial drugs active against this important family of bacterial virulence targets.
Collapse
|
24
|
Landeta C, Boyd D, Beckwith J. Disulfide bond formation in prokaryotes. Nat Microbiol 2018; 3:270-280. [PMID: 29463925 DOI: 10.1038/s41564-017-0106-2] [Citation(s) in RCA: 90] [Impact Index Per Article: 15.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/02/2016] [Accepted: 12/21/2017] [Indexed: 12/25/2022]
Abstract
Interest in protein disulfide bond formation has recently increased because of the prominent role of disulfide bonds in bacterial virulence and survival. The first discovered pathway that introduces disulfide bonds into cell envelope proteins consists of Escherichia coli enzymes DsbA and DsbB. Since its discovery, variations on the DsbAB pathway have been found in bacteria and archaea, probably reflecting specific requirements for survival in their ecological niches. One variation found amongst Actinobacteria and Cyanobacteria is the replacement of DsbB by a homologue of human vitamin K epoxide reductase. Many Gram-positive bacteria express enzymes involved in disulfide bond formation that are similar, but non-homologous, to DsbAB. While bacterial pathways promote disulfide bond formation in the bacterial cell envelope, some archaeal extremophiles express proteins with disulfide bonds both in the cytoplasm and in the extra-cytoplasmic space, possibly to stabilize proteins in the face of extreme conditions, such as growth at high temperatures. Here, we summarize the diversity of disulfide-bond-catalysing systems across prokaryotic lineages, discuss examples for understanding the biological basis of such systems, and present perspectives on how such systems are enabling advances in biomedical engineering and drug development.
Collapse
Affiliation(s)
- Cristina Landeta
- Department of Microbiology and Immunobiology, Harvard Medical School, Boston, MA, USA
| | - Dana Boyd
- Department of Microbiology and Immunobiology, Harvard Medical School, Boston, MA, USA
| | - Jon Beckwith
- Department of Microbiology and Immunobiology, Harvard Medical School, Boston, MA, USA.
| |
Collapse
|
25
|
A shape-shifting redox foldase contributes to Proteus mirabilis copper resistance. Nat Commun 2017; 8:16065. [PMID: 28722010 PMCID: PMC5524982 DOI: 10.1038/ncomms16065] [Citation(s) in RCA: 19] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/07/2016] [Accepted: 05/24/2017] [Indexed: 01/11/2023] Open
Abstract
Copper resistance is a key virulence trait of the uropathogen Proteus mirabilis. Here we show that P. mirabilis ScsC (PmScsC) contributes to this defence mechanism by enabling swarming in the presence of copper. We also demonstrate that PmScsC is a thioredoxin-like disulfide isomerase but, unlike other characterized proteins in this family, it is trimeric. PmScsC trimerization and its active site cysteine are required for wild-type swarming activity in the presence of copper. Moreover, PmScsC exhibits unprecedented motion as a consequence of a shape-shifting motif linking the catalytic and trimerization domains. The linker accesses strand, loop and helical conformations enabling the sampling of an enormous folding landscape by the catalytic domains. Mutation of the shape-shifting motif abolishes disulfide isomerase activity, as does removal of the trimerization domain, showing that both features are essential to foldase function. More broadly, the shape-shifter peptide has the potential for ‘plug and play’ application in protein engineering. Bacterial disulfide isomerases shuffle incorrect disulfide bonds. Here, the authors structurally characterize the disulfide isomerase ScsC from Proteus mirabilis and identify a functionally important shape-shifting motif that allows ScsC to adopt a diverse range of conformations and enable swarming in the presence of copper stress.
Collapse
|
26
|
Bacterial thiol oxidoreductases - from basic research to new antibacterial strategies. Appl Microbiol Biotechnol 2017; 101:3977-3989. [PMID: 28409380 PMCID: PMC5403849 DOI: 10.1007/s00253-017-8291-8] [Citation(s) in RCA: 18] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/06/2017] [Revised: 04/03/2017] [Accepted: 04/04/2017] [Indexed: 12/15/2022]
Abstract
The recent, rapid increase in bacterial antimicrobial resistance has become a major public health concern. One approach to generate new classes of antibacterials is targeting virulence rather than the viability of bacteria. Proteins of the Dsb system, which play a key role in the virulence of many pathogenic microorganisms, represent potential new drug targets. The first part of the article presents current knowledge of how the Dsb system impacts function of various protein secretion systems that influence the virulence of many pathogenic bacteria. Next, the review describes methods used to study the structure, biochemistry, and microbiology of the Dsb proteins and shows how these experiments broaden our knowledge about their function. The lessons gained from basic research have led to a specific search for inhibitors blocking the Dsb networks.
Collapse
|
27
|
Christensen S, Grøftehauge MK, Byriel K, Huston WM, Furlong E, Heras B, Martin JL, McMahon RM. Structural and Biochemical Characterization of Chlamydia trachomatis DsbA Reveals a Cysteine-Rich and Weakly Oxidising Oxidoreductase. PLoS One 2016; 11:e0168485. [PMID: 28030602 PMCID: PMC5193440 DOI: 10.1371/journal.pone.0168485] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/05/2016] [Accepted: 11/30/2016] [Indexed: 11/24/2022] Open
Abstract
The Gram negative bacteria Chlamydia trachomatis is an obligate intracellular human pathogen that can cause pelvic inflammatory disease, infertility and blinding trachoma. C. trachomatis encodes a homolog of the dithiol oxidoreductase DsbA. Bacterial DsbA proteins introduce disulfide bonds to folding proteins providing structural bracing for secreted virulence factors, consequently these proteins are potential targets for antimicrobial drugs. Despite sharing functional and structural characteristics, the DsbA enzymes studied to date vary widely in their redox character. In this study we show that the truncated soluble form of the predicted membrane anchored protein C. trachomatis DsbA (CtDsbA) has oxidase activity and redox properties broadly similar to other characterized DsbA proteins. However CtDsbA is distinguished from other DsbAs by having six cysteines, including a second disulfide bond, and an unusual dipeptide sequence in its catalytic motif (Cys-Ser-Ala-Cys). We report the 2.7 Å crystal structure of CtDsbA revealing a typical DsbA fold, which is most similar to that of DsbA-II type proteins. Consistent with this, the catalytic surface of CtDsbA is negatively charged and lacks the hydrophobic groove found in EcDsbA and DsbAs from other enterobacteriaceae. Biochemical characterization of CtDsbA reveals it to be weakly oxidizing compared to other DsbAs and with only a mildly destabilizing active site disulfide bond. Analysis of the crystal structure suggests that this redox character is consistent with a lack of contributing factors to stabilize the active site nucleophilic thiolate relative to more oxidizing DsbA proteins.
Collapse
Affiliation(s)
- Signe Christensen
- Division of Chemistry and Structural Biology, Institute for Molecular Bioscience, University of Queensland, St. Lucia, Queensland, Australia
| | - Morten K. Grøftehauge
- Division of Chemistry and Structural Biology, Institute for Molecular Bioscience, University of Queensland, St. Lucia, Queensland, Australia
| | - Karl Byriel
- Division of Chemistry and Structural Biology, Institute for Molecular Bioscience, University of Queensland, St. Lucia, Queensland, Australia
| | - Wilhelmina M. Huston
- School of Life Sciences, University of Technology Sydney, Broadway, New South Wales, Australia
| | - Emily Furlong
- Division of Chemistry and Structural Biology, Institute for Molecular Bioscience, University of Queensland, St. Lucia, Queensland, Australia
| | - Begoña Heras
- Division of Chemistry and Structural Biology, Institute for Molecular Bioscience, University of Queensland, St. Lucia, Queensland, Australia
| | - Jennifer L. Martin
- Division of Chemistry and Structural Biology, Institute for Molecular Bioscience, University of Queensland, St. Lucia, Queensland, Australia
- * E-mail: (JM); (RM)
| | - Róisín M. McMahon
- Division of Chemistry and Structural Biology, Institute for Molecular Bioscience, University of Queensland, St. Lucia, Queensland, Australia
- * E-mail: (JM); (RM)
| |
Collapse
|
28
|
Smith RP, Paxman JJ, Scanlon MJ, Heras B. Targeting Bacterial Dsb Proteins for the Development of Anti-Virulence Agents. Molecules 2016; 21:molecules21070811. [PMID: 27438817 PMCID: PMC6273893 DOI: 10.3390/molecules21070811] [Citation(s) in RCA: 44] [Impact Index Per Article: 5.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/26/2016] [Revised: 05/21/2016] [Accepted: 05/25/2016] [Indexed: 11/22/2022] Open
Abstract
Recent years have witnessed a dramatic increase in bacterial antimicrobial resistance and a decline in the development of novel antibiotics. New therapeutic strategies are urgently needed to combat the growing threat posed by multidrug resistant bacterial infections. The Dsb disulfide bond forming pathways are potential targets for the development of antimicrobial agents because they play a central role in bacterial pathogenesis. In particular, the DsbA/DsbB system catalyses disulfide bond formation in a wide array of virulence factors, which are essential for many pathogens to establish infections and cause disease. These redox enzymes are well placed as antimicrobial targets because they are taxonomically widespread, share low sequence identity with human proteins, and many years of basic research have provided a deep molecular understanding of these systems in bacteria. In this review, we discuss disulfide bond catalytic pathways in bacteria and their significance in pathogenesis. We also review the use of different approaches to develop inhibitors against Dsb proteins as potential anti-virulence agents, including fragment-based drug discovery, high-throughput screening and other structure-based drug discovery methods.
Collapse
Affiliation(s)
- Roxanne P Smith
- Department of Biochemistry and Genetics, La Trobe Institute for Molecular Science, La Trobe University, Kingsbury Drive, Bundoora, Vic 3083, Australia.
| | - Jason J Paxman
- Department of Biochemistry and Genetics, La Trobe Institute for Molecular Science, La Trobe University, Kingsbury Drive, Bundoora, Vic 3083, Australia.
| | - Martin J Scanlon
- Medicinal Chemistry, Monash Institute of Pharmaceutical Sciences, Monash University, Royal Parade, Parkville, Vic 3052, Australia.
| | - Begoña Heras
- Department of Biochemistry and Genetics, La Trobe Institute for Molecular Science, La Trobe University, Kingsbury Drive, Bundoora, Vic 3083, Australia.
| |
Collapse
|
29
|
Abstract
Disulfide bonds are important for the stability and function of many secreted proteins. In Gram-negative bacteria, these linkages are catalyzed by thiol-disulfide oxidoreductases (Dsb) in the periplasm. Protein oxidation has been well studied in these organisms, but it has not fully been explored in Gram-positive bacteria, which lack traditional periplasmic compartments. Recent bioinformatics analyses have suggested that the high-GC-content bacteria (i.e., actinobacteria) rely on disulfide-bond-forming pathways. In support of this, Dsb-like proteins have been identified in Mycobacterium tuberculosis, but their functions are not known. Actinomyces oris and Corynebacterium diphtheriae have recently emerged as models to study disulfide bond formation in actinobacteria. In both organisms, disulfide bonds are catalyzed by the membrane-bound oxidoreductase MdbA. Remarkably, unlike known Dsb proteins, MdbA is important for pathogenesis and growth, which makes it a potential target for new antibacterial drugs. This review will discuss disulfide-bond-forming pathways in bacteria, with a special focus on Gram-positive bacteria.
Collapse
|
30
|
Altered Escherichia coli membrane protein assembly machinery allows proper membrane assembly of eukaryotic protein vitamin K epoxide reductase. Proc Natl Acad Sci U S A 2015; 112:15184-9. [PMID: 26598701 DOI: 10.1073/pnas.1521260112] [Citation(s) in RCA: 10] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/29/2022] Open
Abstract
Functional overexpression of polytopic membrane proteins, particularly when in a foreign host, is often a challenging task. Factors that negatively affect such processes are poorly understood. Using the mammalian membrane protein vitamin K epoxide reductase (VKORc1) as a reporter, we describe a genetic selection approach allowing the isolation of Escherichia coli mutants capable of functionally expressing this blood-coagulation enzyme. The isolated mutants map to components of membrane protein assembly and quality control proteins YidC and HslV. We show that changes in the VKORc1 sequence and in the YidC hydrophilic groove along with the inactivation of HslV promote VKORc1 activity and dramatically increase its expression level. We hypothesize that such changes correct for mismatches in the membrane topogenic signals between E. coli and eukaryotic cells guiding proper membrane integration. Furthermore, the obtained mutants allow the study of VKORc1 reaction mechanisms, inhibition by warfarin, and the high-throughput screening for potential anticoagulants.
Collapse
|
31
|
Abstract
Antibacterial drugs with novel scaffolds and new mechanisms of action are desperately needed to address the growing problem of antibiotic resistance. The periplasmic oxidative folding system in Gram-negative bacteria represents a possible target for anti-virulence antibacterials. By targeting virulence rather than viability, development of resistance and side effects (through killing host native microbiota) might be minimized. Here, we undertook the design of peptidomimetic inhibitors targeting the interaction between the two key enzymes of oxidative folding, DsbA and DsbB, with the ultimate goal of preventing virulence factor assembly. Structures of DsbB - or peptides - complexed with DsbA revealed key interactions with the DsbA active site cysteine, and with a hydrophobic groove adjacent to the active site. The present work aimed to discover peptidomimetics that target the hydrophobic groove to generate non-covalent DsbA inhibitors. The previously reported structure of a Proteus mirabilis DsbA active site cysteine mutant, in a non-covalent complex with the heptapeptide PWATCDS, was used as an in silico template for virtual screening of a peptidomimetic fragment library. The highest scoring fragment compound and nine derivatives were synthesized and evaluated for DsbA binding and inhibition. These experiments discovered peptidomimetic fragments with inhibitory activity at millimolar concentrations. Although only weakly potent relative to larger covalent peptide inhibitors that interact through the active site cysteine, these fragments offer new opportunities as templates to build non-covalent inhibitors. The results suggest that non-covalent peptidomimetics may need to interact with sites beyond the hydrophobic groove in order to produce potent DsbA inhibitors.
Collapse
|
32
|
Bocian-Ostrzycka KM, Grzeszczuk MJ, Dziewit L, Jagusztyn-Krynicka EK. Diversity of the Epsilonproteobacteria Dsb (disulfide bond) systems. Front Microbiol 2015; 6:570. [PMID: 26106374 PMCID: PMC4460558 DOI: 10.3389/fmicb.2015.00570] [Citation(s) in RCA: 14] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/18/2015] [Accepted: 05/24/2015] [Indexed: 12/20/2022] Open
Abstract
The bacterial proteins of the Dsb family-important components of the post-translational protein modification system-catalyze the formation of disulfide bridges, a process that is crucial for protein structure stabilization and activity. Dsb systems play an essential role in the assembly of many virulence factors. Recent rapid advances in global analysis of bacteria have thrown light on the enormous diversity among bacterial Dsb systems. While the Escherichia coli disulfide bond-forming system is quite well understood, the mechanisms of action of Dsb systems in other bacteria, including members of class Epsilonproteobacteria that contain pathogenic and non-pathogenic bacteria colonizing extremely diverse ecological niches, are poorly characterized. Here we present a review of current knowledge on Epsilonproteobacteria Dsb systems. We have focused on the Dsb systems of Campylobacter spp. and Helicobacter spp. because our knowledge about Dsb proteins of Wolinella and Arcobacter spp. is still scarce and comes mainly from bioinformatic studies. Helicobacter pylori is a common human pathogen that colonizes the gastric epithelium of humans with severe consequences. Campylobacter spp. is a leading cause of zoonotic enteric bacterial infections in most developed and developing nations. We focus on various aspects of the diversity of the Dsb systems and their influence on pathogenicity, particularly because Dsb proteins are considered as potential targets for a new class of anti-virulence drugs to treat human infections by Campylobacter or Helicobacter spp.
Collapse
|