1
|
Schiffrin B, Crossley JA, Walko M, Machin JM, Nasir Khan G, Manfield IW, Wilson AJ, Brockwell DJ, Fessl T, Calabrese AN, Radford SE, Zhuravleva A. Dual client binding sites in the ATP-independent chaperone SurA. Nat Commun 2024; 15:8071. [PMID: 39277579 PMCID: PMC11401910 DOI: 10.1038/s41467-024-52021-1] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/19/2024] [Accepted: 08/23/2024] [Indexed: 09/17/2024] Open
Abstract
The ATP-independent chaperone SurA protects unfolded outer membrane proteins (OMPs) from aggregation in the periplasm of Gram-negative bacteria, and delivers them to the β-barrel assembly machinery (BAM) for folding into the outer membrane (OM). Precisely how SurA recognises and binds its different OMP clients remains unclear. Escherichia coli SurA comprises three domains: a core and two PPIase domains (P1 and P2). Here, by combining methyl-TROSY NMR, single-molecule Förster resonance energy transfer (smFRET), and bioinformatics analyses we show that SurA client binding is mediated by two binding hotspots in the core and P1 domains. These interactions are driven by aromatic-rich motifs in the client proteins, leading to SurA core/P1 domain rearrangements and expansion of clients from collapsed, non-native states. We demonstrate that the core domain is key to OMP expansion by SurA, and uncover a role for SurA PPIase domains in limiting the extent of expansion. The results reveal insights into SurA-OMP recognition and the mechanism of activation for an ATP-independent chaperone, and suggest a route to targeting the functions of a chaperone key to bacterial virulence and OM integrity.
Collapse
Affiliation(s)
- Bob Schiffrin
- Astbury Centre for Structural Molecular Biology, School of Molecular and Cellular Biology, Faculty of Biological Sciences, University of Leeds, Leeds, UK
| | - Joel A Crossley
- Astbury Centre for Structural Molecular Biology, School of Molecular and Cellular Biology, Faculty of Biological Sciences, University of Leeds, Leeds, UK
| | - Martin Walko
- Astbury Centre for Structural Molecular Biology, School of Molecular and Cellular Biology, Faculty of Biological Sciences, University of Leeds, Leeds, UK
- Astbury Centre for Structural Molecular Biology, School of Chemistry, University of Leeds, Leeds, UK
| | - Jonathan M Machin
- Astbury Centre for Structural Molecular Biology, School of Molecular and Cellular Biology, Faculty of Biological Sciences, University of Leeds, Leeds, UK
| | - G Nasir Khan
- Astbury Centre for Structural Molecular Biology, School of Molecular and Cellular Biology, Faculty of Biological Sciences, University of Leeds, Leeds, UK
| | - Iain W Manfield
- Astbury Centre for Structural Molecular Biology, School of Molecular and Cellular Biology, Faculty of Biological Sciences, University of Leeds, Leeds, UK
| | - Andrew J Wilson
- Astbury Centre for Structural Molecular Biology, School of Chemistry, University of Leeds, Leeds, UK
- School of Chemistry, University of Birmingham, Edgbaston, Birmingham, UK
| | - David J Brockwell
- Astbury Centre for Structural Molecular Biology, School of Molecular and Cellular Biology, Faculty of Biological Sciences, University of Leeds, Leeds, UK
| | - Tomas Fessl
- Faculty of Science, University of South Bohemia, České Budějovice, Czech Republic
| | - Antonio N Calabrese
- Astbury Centre for Structural Molecular Biology, School of Molecular and Cellular Biology, Faculty of Biological Sciences, University of Leeds, Leeds, UK
| | - Sheena E Radford
- Astbury Centre for Structural Molecular Biology, School of Molecular and Cellular Biology, Faculty of Biological Sciences, University of Leeds, Leeds, UK.
| | - Anastasia Zhuravleva
- Astbury Centre for Structural Molecular Biology, School of Molecular and Cellular Biology, Faculty of Biological Sciences, University of Leeds, Leeds, UK.
| |
Collapse
|
2
|
Pumirat P, Santajit S, Tunyong W, Kong-Ngoen T, Tandhavanant S, Lohitthai S, Rungruengkitkun A, Chantratita N, Ampawong S, Reamtong O, Indrawattana N. Impact of AbaI mutation on virulence, biofilm development, and antibiotic susceptibility in Acinetobacter baumannii. Sci Rep 2024; 14:21521. [PMID: 39277662 PMCID: PMC11401864 DOI: 10.1038/s41598-024-72740-1] [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: 05/17/2024] [Accepted: 09/10/2024] [Indexed: 09/17/2024] Open
Abstract
The quorum sensing (QS) system mediated by the abaI gene in Acinetobacter baumannii is crucial for various physiological and pathogenic processes. In this study, we constructed a stable markerless abaI knockout mutant (ΔabaI) strain using a pEXKm5-based allele replacement method to investigate the impact of abaI on A. baumannii. Proteomic analysis revealed significant alterations in protein expression between the wild type (WT) and ΔabaI mutant strains, particularly in proteins associated with membrane structure, antibiotic resistance, and virulence. Notably, the downregulation of key outer membrane proteins such as SurA, OmpA, OmpW, and BamA suggests potential vulnerabilities in outer membrane integrity, which correlate with structural abnormalities in the ΔabaI mutant strain, including irregular cell shapes and compromised membrane integrity, observed by scanning and transmission electron microscopy. Furthermore, diminished expression of regulatory proteins such as OmpR and GacA-GacS highlights the broader regulatory networks affected by abaI deletion. Functional assays revealed impaired biofilm formation and surface-associated motility in the mutant strain, indicative of altered colonization capabilities. Interestingly, the mutant showed a complex antibiotic susceptibility profile. While it demonstrated increased susceptibility to membrane-targeting antibiotics, its response to beta-lactams was more nuanced. Despite increased expression of metallo-beta-lactamase (MBL) superfamily proteins and DcaP-like protein, the mutant unexpectedly showed lower MICs for carbapenems (imipenem and meropenem) compared to the wild-type strain. This suggests that abaI deletion affects antibiotic susceptibility through multiple, potentially competing mechanisms. Further investigation is needed to fully elucidate the interplay between quorum sensing, antibiotic resistance genes, and overall antibiotic susceptibility in A. baumannii. Our findings underscore the multifaceted role of the abaI gene in modulating various cellular processes and highlight its significance in A. baumannii physiology, pathogenesis, and antibiotic resistance. Targeting the abaI QS system may offer novel therapeutic strategies for this clinically significant pathogen.
Collapse
Affiliation(s)
- Pornpan Pumirat
- Department of Microbiology and Immunology, Mahidol University, Bangkok, Thailand
| | - Sirijan Santajit
- Department of Medical Technology, School of Allied Health Sciences, Walailak University, Nakhon Si Thammarat, Thailand
| | - Witawat Tunyong
- Department of Microbiology and Immunology, Mahidol University, Bangkok, Thailand
| | - Thida Kong-Ngoen
- Department of Microbiology and Immunology, Mahidol University, Bangkok, Thailand
| | - Sarunporn Tandhavanant
- Department of Microbiology and Immunology, Mahidol University, Bangkok, Thailand
- Department of Bacteriology, Institute of Tropical Medicine, Nagasaki University, Nagasaki, Japan
| | - Sanisa Lohitthai
- Department of Microbiology and Immunology, Mahidol University, Bangkok, Thailand
| | | | - Narisara Chantratita
- Department of Microbiology and Immunology, Mahidol University, Bangkok, Thailand
| | - Sumate Ampawong
- Department of Tropical Pathology, Faculty of Tropical Medicine, Mahidol University, Bangkok, Thailand
| | - Onrapak Reamtong
- Department of Tropical Molecular Biology and Genetics, Faculty of Tropical Medicine, Mahidol University, Bangkok, Thailand
| | - Nitaya Indrawattana
- Biomedical Research Incubator Unit, Department of Research, Faculty of Medicine Siriraj Hospital, Mahidol University, Bangkok, Thailand.
- Department of Research, Siriraj Center of Research Excellence in Allergy and Immunology, Faculty of Medicine Siriraj Hospital, Mahidol University, Bangkok, Thailand.
| |
Collapse
|
3
|
Li S, Wang Y, Yang R, Zhu X, Bai H, Deng X, Bai J, Zhang Y, Xiao Y, Li Z, Liu Z, Zhou Z. Outer membrane protein OMP76 of Riemerella anatipestifer contributes to complement evasion and virulence by binding to duck complement factor vitronectin. Virulence 2023; 14:2223060. [PMID: 37326479 PMCID: PMC10281475 DOI: 10.1080/21505594.2023.2223060] [Citation(s) in RCA: 2] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/21/2023] [Revised: 05/26/2023] [Accepted: 06/05/2023] [Indexed: 06/17/2023] Open
Abstract
Riemerella anatipestifer is an important bacterial pathogen in poultry. Pathogenic bacteria recruit host complement factors to resist the bactericidal effect of serum complement. Vitronectin (Vn) is a complementary regulatory protein that inhibits the formation of the membrane attack complex (MAC). Microbes use outer membrane proteins (OMPs) to hijack Vn for complement evasion. However, the mechanism by which R. anatipestifer achieves evasion is unclear. This study aimed to characterise OMPs of R. anatipestifer which interact with duck Vn (dVn) during complement evasion. Far-western assays and comparison of wild-type and mutant strains that were treated with dVn and duck serum demonstrated particularly strong binding of OMP76 to dVn. These data were confirmed with Escherichia coli strains expressing and not expressing OMP76. Combining tertiary structure analysis and homology modelling, truncated and knocked-out fragments of OMP76 showed that a cluster of critical amino acids in an extracellular loop of OMP76 mediate the interaction with dVn. Moreover, binding of dVn to R. anatipestifer inhibited MAC deposition on the bacterial surface thereby enhancing survival in duck serum. Virulence of the mutant strain ΔOMP76 was attenuated significantly relative to the wild-type strain. Furthermore, adhesion and invasion abilities of ΔOMP76 decreased, and histopathological changes showed that ΔOMP76 was less virulent in ducklings. Thus, OMP76 is a key virulence factor of R. anatipestifer. The identification of OMP76-mediated evasion of complement by recruitment of dVn contributes significantly to the understanding of the molecular mechanism by which R. anatipestifer escapes host innate immunity and provides a new target for the development of subunit vaccines.
Collapse
Affiliation(s)
- Sen Li
- College of Veterinary Medicine, Huazhong Agricultural University, Wuhan, China
- State Key Laboratory of Agricultural Microbiology, Huazhong Agricultural University, Wuhan, China
- Key Laboratory of Preventive Veterinary Medicine in Hubei Province, Huazhong Agricultural University, Wuhan, China
- Hubei Hongshan Laboratory, Huazhong Agricultural University, Wuhan, China
| | - Yanhua Wang
- College of Veterinary Medicine, Huazhong Agricultural University, Wuhan, China
- State Key Laboratory of Agricultural Microbiology, Huazhong Agricultural University, Wuhan, China
- Key Laboratory of Preventive Veterinary Medicine in Hubei Province, Huazhong Agricultural University, Wuhan, China
- Hubei Hongshan Laboratory, Huazhong Agricultural University, Wuhan, China
| | - Rongkun Yang
- College of Veterinary Medicine, Huazhong Agricultural University, Wuhan, China
- State Key Laboratory of Agricultural Microbiology, Huazhong Agricultural University, Wuhan, China
- Key Laboratory of Preventive Veterinary Medicine in Hubei Province, Huazhong Agricultural University, Wuhan, China
- Hubei Hongshan Laboratory, Huazhong Agricultural University, Wuhan, China
| | - Xiaotong Zhu
- College of Veterinary Medicine, Huazhong Agricultural University, Wuhan, China
- State Key Laboratory of Agricultural Microbiology, Huazhong Agricultural University, Wuhan, China
- Key Laboratory of Preventive Veterinary Medicine in Hubei Province, Huazhong Agricultural University, Wuhan, China
| | - Hongying Bai
- College of Veterinary Medicine, Huazhong Agricultural University, Wuhan, China
- State Key Laboratory of Agricultural Microbiology, Huazhong Agricultural University, Wuhan, China
- Key Laboratory of Preventive Veterinary Medicine in Hubei Province, Huazhong Agricultural University, Wuhan, China
| | - Xiaojian Deng
- College of Veterinary Medicine, Huazhong Agricultural University, Wuhan, China
- State Key Laboratory of Agricultural Microbiology, Huazhong Agricultural University, Wuhan, China
- Key Laboratory of Preventive Veterinary Medicine in Hubei Province, Huazhong Agricultural University, Wuhan, China
| | - Jiao Bai
- College of Veterinary Medicine, Huazhong Agricultural University, Wuhan, China
- State Key Laboratory of Agricultural Microbiology, Huazhong Agricultural University, Wuhan, China
- Key Laboratory of Preventive Veterinary Medicine in Hubei Province, Huazhong Agricultural University, Wuhan, China
| | - Yang Zhang
- College of Veterinary Medicine, Huazhong Agricultural University, Wuhan, China
- State Key Laboratory of Agricultural Microbiology, Huazhong Agricultural University, Wuhan, China
- Key Laboratory of Preventive Veterinary Medicine in Hubei Province, Huazhong Agricultural University, Wuhan, China
| | - Yuncai Xiao
- College of Veterinary Medicine, Huazhong Agricultural University, Wuhan, China
- State Key Laboratory of Agricultural Microbiology, Huazhong Agricultural University, Wuhan, China
- Key Laboratory of Preventive Veterinary Medicine in Hubei Province, Huazhong Agricultural University, Wuhan, China
| | - Zili Li
- College of Veterinary Medicine, Huazhong Agricultural University, Wuhan, China
- State Key Laboratory of Agricultural Microbiology, Huazhong Agricultural University, Wuhan, China
- Key Laboratory of Preventive Veterinary Medicine in Hubei Province, Huazhong Agricultural University, Wuhan, China
| | - Zhengfei Liu
- College of Veterinary Medicine, Huazhong Agricultural University, Wuhan, China
- State Key Laboratory of Agricultural Microbiology, Huazhong Agricultural University, Wuhan, China
- Key Laboratory of Preventive Veterinary Medicine in Hubei Province, Huazhong Agricultural University, Wuhan, China
| | - Zutao Zhou
- College of Veterinary Medicine, Huazhong Agricultural University, Wuhan, China
- State Key Laboratory of Agricultural Microbiology, Huazhong Agricultural University, Wuhan, China
- Key Laboratory of Preventive Veterinary Medicine in Hubei Province, Huazhong Agricultural University, Wuhan, China
- Hubei Hongshan Laboratory, Huazhong Agricultural University, Wuhan, China
| |
Collapse
|
4
|
SurA-like and Skp-like Proteins as Important Virulence Determinants of the Gram Negative Bacterial Pathogens. Int J Mol Sci 2022; 24:ijms24010295. [PMID: 36613738 PMCID: PMC9820271 DOI: 10.3390/ijms24010295] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/02/2022] [Revised: 12/19/2022] [Accepted: 12/20/2022] [Indexed: 12/28/2022] Open
Abstract
In the Gram-negative bacteria, many important virulence factors reach their destination via two-step export systems, and they must traverse the periplasmic space before reaching the outer membrane. Since these proteins must be maintained in a structure competent for transport into or across the membrane, they frequently require the assistance of chaperones. Based on the results obtained for the model bacterium Escherichia coli and related species, it is assumed that in the biogenesis of the outer membrane proteins and the periplasmic transit of secretory proteins, the SurA peptidyl-prolyl isomerase/chaperone plays a leading role, while the Skp chaperone is rather of secondary importance. However, detailed studies carried out on several other Gram-negative pathogens indicate that the importance of individual chaperones in the folding and transport processes depends on the properties of client proteins and is species-specific. Taking into account the importance of SurA functions in bacterial virulence and severity of phenotypes due to surA mutations, this folding factor is considered as a putative therapeutic target to combat microbial infections. In this review, we present recent findings regarding SurA and Skp proteins: their mechanisms of action, involvement in processes related to virulence, and perspectives to use them as therapeutic targets.
Collapse
|
5
|
Svirina A, Chamachi N, Schlierf M. Single‐molecule approaches reveal outer membrane protein biogenesis dynamics. Bioessays 2022; 44:e2200149. [DOI: 10.1002/bies.202200149] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/01/2022] [Revised: 10/03/2022] [Accepted: 10/05/2022] [Indexed: 11/10/2022]
Affiliation(s)
- Anna Svirina
- TU Dresden B CUBE – Center for Molecular Bioengineering Dresden Germany
| | - Neharika Chamachi
- TU Dresden B CUBE – Center for Molecular Bioengineering Dresden Germany
| | - Michael Schlierf
- TU Dresden B CUBE – Center for Molecular Bioengineering Dresden Germany
- Cluster of Excellence Physics of Life Technische Universität Dresden Dresden Germany
| |
Collapse
|
6
|
Dynamic interplay between the periplasmic chaperone SurA and the BAM complex in outer membrane protein folding. Commun Biol 2022; 5:560. [PMID: 35676411 PMCID: PMC9177699 DOI: 10.1038/s42003-022-03502-w] [Citation(s) in RCA: 7] [Impact Index Per Article: 3.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/06/2022] [Accepted: 05/18/2022] [Indexed: 12/12/2022] Open
Abstract
Correct folding of outer membrane proteins (OMPs) into the outer membrane of Gram-negative bacteria depends on delivery of unfolded OMPs to the β-barrel assembly machinery (BAM). How unfolded substrates are presented to BAM remains elusive, but the major OMP chaperone SurA is proposed to play a key role. Here, we have used hydrogen deuterium exchange mass spectrometry (HDX-MS), crosslinking, in vitro folding and binding assays and computational modelling to show that the core domain of SurA and one of its two PPIase domains are key to the SurA-BAM interaction and are required for maximal catalysis of OMP folding. We reveal that binding causes changes in BAM and SurA conformation and/or dynamics distal to the sites of binding, including at the BamA β1-β16 seam. We propose a model for OMP biogenesis in which SurA plays a crucial role in OMP delivery and primes BAM to accept substrates for folding. Interaction of the outer membrane protein (OMP) chaperone SurA and the OMP folding catalyst BAM results in changes in the conformational ensembles of both species, suggesting a mechanism for delivery of OMPs to BAM in Gram-negative bacteria.
Collapse
|
7
|
Guillén S, Marcén M, Fau E, Mañas P, Cebrián G. Relationship between growth ability, virulence, and resistance to food-processing related stresses in non-typhoidal Salmonellae. Int J Food Microbiol 2022; 361:109462. [PMID: 34749188 DOI: 10.1016/j.ijfoodmicro.2021.109462] [Citation(s) in RCA: 7] [Impact Index Per Article: 3.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/04/2021] [Revised: 10/01/2021] [Accepted: 10/25/2021] [Indexed: 11/29/2022]
Abstract
The ability of Salmonella to resist and adapt to harsh conditions is one of the major features that have made this microorganism such a relevant health hazard. However, the impact of these resistance responses on other aspects of Salmonella physiology, such as virulence and growth ability, is still not fully understood. The objective of this study was to determine the maximum growth rates (in three different media), virulence (adhesion and invasion of Caco-2 cells), and other phenotypic characteristics (biofilm-forming ability and antimicrobial resistance) of 23 Salmonella strains belonging to different serovars, and to compare them with their previously determined stress resistance parameters. Significant differences (p < 0.05) in growth rates, virulence, and biofilm-forming ability were found among the 23 strains studied. Nevertheless, whereas less than 3-fold change between the lowest and the highest growth rate was observed, the percentage of cells capable of invading Caco-2 cells varied more than 100-fold, that to form biofilms more than 30-fold, and the antibiotic MICs varied up to 512-fold, among the different strains. Results indicate that those strains with the highest cell adhesion ability were not always the most invasive ones and suggest that, in general terms, a higher stress resistance did not imply a reduced growth ability (rate). Similarly, no association between stress resistance and biofilm formation ability (except for acid stress) or antibiotic resistance (with minor exceptions) was found. Our data also suggest that, in Salmonella, acid stress resistance would be associated with virulence, since a positive correlation of that trait with adhesion and a negative correlation with invasion was found. This study contributes to a better understanding of the physiology of Salmonella and the relationship between bacterial stress resistance, growth ability, and virulence. It also provides new data regarding intra-specific variability of a series of phenotypic characteristics of Salmonella that are relevant from the food safety perspective.
Collapse
Affiliation(s)
- Silvia Guillén
- Departamento de Producción Animal y Ciencia de los Alimentos, Facultad de Veterinaria, Instituto Agroalimentario de Aragón - IA2 - (Universidad de Zaragoza-CITA), Zaragoza, Spain
| | - María Marcén
- Departamento de Producción Animal y Ciencia de los Alimentos, Facultad de Veterinaria, Instituto Agroalimentario de Aragón - IA2 - (Universidad de Zaragoza-CITA), Zaragoza, Spain
| | - Ester Fau
- Departamento de Producción Animal y Ciencia de los Alimentos, Facultad de Veterinaria, Instituto Agroalimentario de Aragón - IA2 - (Universidad de Zaragoza-CITA), Zaragoza, Spain
| | - Pilar Mañas
- Departamento de Producción Animal y Ciencia de los Alimentos, Facultad de Veterinaria, Instituto Agroalimentario de Aragón - IA2 - (Universidad de Zaragoza-CITA), Zaragoza, Spain
| | - Guillermo Cebrián
- Departamento de Producción Animal y Ciencia de los Alimentos, Facultad de Veterinaria, Instituto Agroalimentario de Aragón - IA2 - (Universidad de Zaragoza-CITA), Zaragoza, Spain.
| |
Collapse
|
8
|
Gao M, Nakajima An D, Skolnick J. Deep learning-driven insights into super protein complexes for outer membrane protein biogenesis in bacteria. eLife 2022; 11:82885. [PMID: 36576775 PMCID: PMC9797188 DOI: 10.7554/elife.82885] [Citation(s) in RCA: 4] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/22/2022] [Accepted: 11/28/2022] [Indexed: 12/29/2022] Open
Abstract
To reach their final destinations, outer membrane proteins (OMPs) of gram-negative bacteria undertake an eventful journey beginning in the cytosol. Multiple molecular machines, chaperones, proteases, and other enzymes facilitate the translocation and assembly of OMPs. These helpers usually associate, often transiently, forming large protein assemblies. They are not well understood due to experimental challenges in capturing and characterizing protein-protein interactions (PPIs), especially transient ones. Using AF2Complex, we introduce a high-throughput, deep learning pipeline to identify PPIs within the Escherichia coli cell envelope and apply it to several proteins from an OMP biogenesis pathway. Among the top confident hits obtained from screening ~1500 envelope proteins, we find not only expected interactions but also unexpected ones with profound implications. Subsequently, we predict atomic structures for these protein complexes. These structures, typically of high confidence, explain experimental observations and lead to mechanistic hypotheses for how a chaperone assists a nascent, precursor OMP emerging from a translocon, how another chaperone prevents it from aggregating and docks to a β-barrel assembly port, and how a protease performs quality control. This work presents a general strategy for investigating biological pathways by using structural insights gained from deep learning-based predictions.
Collapse
Affiliation(s)
- Mu Gao
- Center for the Study of Systems Biology, School of Biological Sciences, Georgia Institute of TechnologyAtlantaUnited States
| | - Davi Nakajima An
- School of Computer Science, Georgia Institute of TechnologyAtlantaUnited States
| | - Jeffrey Skolnick
- Center for the Study of Systems Biology, School of Biological Sciences, Georgia Institute of TechnologyAtlantaUnited States
| |
Collapse
|
9
|
Troman LA, Collinson I. Pushing the Envelope: The Mysterious Journey Through the Bacterial Secretory Machinery, and Beyond. Front Microbiol 2021; 12:782900. [PMID: 34917061 PMCID: PMC8669966 DOI: 10.3389/fmicb.2021.782900] [Citation(s) in RCA: 18] [Impact Index Per Article: 6.0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/24/2021] [Accepted: 11/09/2021] [Indexed: 11/20/2022] Open
Abstract
Gram-negative bacteria are contained by an envelope composed of inner and outer-membranes with the peptidoglycan (PG) layer between them. Protein translocation across the inner membrane for secretion, or insertion into the inner membrane is primarily conducted using the highly conserved, hourglass-shaped channel, SecYEG: the core-complex of the Sec translocon. This transport process is facilitated by interactions with ancillary subcomplex SecDF-YajC (secretion) and YidC (insertion) forming the holo-translocon (HTL). This review recaps the transport process across the inner-membrane and then further explores how delivery and folding into the periplasm or outer-membrane is achieved. It seems very unlikely that proteins are jettisoned into the periplasm and left to their own devices. Indeed, chaperones such as SurA, Skp, DegP are known to play a part in protein folding, quality control and, if necessary degradation. YfgM and PpiD, by their association at the periplasmic surface of the Sec machinery, most probably are also involved in some way. Yet, it is not entirely clear how outer-membrane proteins are smuggled past the proteases and across the PG to the barrel-assembly machinery (BAM) and their final destination. Moreover, how can this be achieved, as is thought, without the input of energy? Recently, we proposed that the Sec and BAM translocons interact with one another, and most likely other factors, to provide a conduit to the periplasm and the outer-membrane. As it happens, numerous other specialized proteins secretion systems also form trans-envelope structures for this very purpose. The direct interaction between components across the envelope raises the prospect of energy coupling from the inner membrane for active transport to the outer-membrane. Indeed, this kind of long-range energy coupling through large inter-membrane assemblies occurs for small molecule import (e.g., nutrient import by the Ton complex) and export (e.g., drug efflux by the AcrAB-TolC complex). This review will consider this hypothetical prospect in the context of outer-membrane protein biogenesis.
Collapse
Affiliation(s)
| | - Ian Collinson
- School of Biochemistry, University of Bristol, Bristol, United Kingdom
| |
Collapse
|
10
|
Kumawat M, Chaudhary D, Nabi B, Kumar M, Sarma DK, Shubham S, Karuna I, Ahlawat N, Ahlawat S. Purification and characterization of Cyclophilin: a protein associated with protein folding in Salmonella Typhimurium. Arch Microbiol 2021; 203:5509-5517. [PMID: 34417854 DOI: 10.1007/s00203-021-02519-9] [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: 06/30/2021] [Revised: 07/30/2021] [Accepted: 08/03/2021] [Indexed: 10/20/2022]
Abstract
Salmonella Typhimurium (ST) is a Gram-negative zoonotic pathogenic bacterium that causes infectious disease in humans as well as in animals. It causes foodborne diarrheal or gastrointestinal illness and fever called salmonellosis, which is a leading cause of millions of deaths worldwide. Salmonellaenterica serovar Typhimurium (S. Typhimurium) during its pathogenesis take away the actin cytoskeleton of their host cells and this is the crucial step of its infection cycle. Cyclophilin A, a type of peptidyl-prolyl isomerase that's encoded by the ppiA gene in ST, plays pleiotropic roles in maintaining bacterial physiology. In this investigation, the proteomic characterization of the peptidyl-prolyl cis-trans isomerase- A (Cyclophilin A) from Salmonella Typhimurium is reported. Cyclophilin A (CypA) protein from Salmonella Typhimurium proved to be highly conserved and homologous protein sequence compared to other organisms. This protein was expressed in Escherichia coli followed by its purification in a recombinant form protein exhibited a characteristic PPIases activity (Vmax = 0.8752 ± 0.13892 µmoles/min, Km = 0.9315 ± 0.5670 µM) in comparison to control. The mass spectrometry analysis of Cyp A protein-peptide showed a highest sequence similarity with the cyclophilin protein of Salmonella. PPIases proteins (enzyme) data suggest that Ppi-A has roles in the protein folding that may be contributing to the virulence of Salmonella by isomerization of protein outline. These results suggest an active and vital role of this protein in protein folding along with regulation in Salmonella Typhimurium.
Collapse
Affiliation(s)
- Manoj Kumawat
- Department of Microbiology, ICMR National Institute for Research in Environmental Health, Bhopal, 462030, India.
- Department of Biochemistry and Biochemical Engineering, SHUATS, Sam Higginbottom University of Agriculture, Technology and Sciences, Allahabad, 211007, India.
| | - Divya Chaudhary
- Department of Biotechnology and Microbiology, Meerut Institute of Engineering and Technology, Meerut, 250005, India
| | - Bilkees Nabi
- Department of Biochemistry and Biochemical Engineering, SHUATS, Sam Higginbottom University of Agriculture, Technology and Sciences, Allahabad, 211007, India
| | - Manoj Kumar
- Department of Microbiology, ICMR National Institute for Research in Environmental Health, Bhopal, 462030, India
| | - Devojit Kumar Sarma
- Department of Microbiology, ICMR National Institute for Research in Environmental Health, Bhopal, 462030, India
| | - Swasti Shubham
- Department of Microbiology, ICMR National Institute for Research in Environmental Health, Bhopal, 462030, India
| | - Irungbam Karuna
- Divisions of Biochemistry, Indian Veterinary Research Institute, Izatnagar, Bareilly, 243122 , India
| | - Neeraj Ahlawat
- Department of Animal Husbandry and Dairying, SHUATS, Prayagraj , 211007, India
| | - Sushma Ahlawat
- Department of Biochemistry and Biochemical Engineering, SHUATS, Sam Higginbottom University of Agriculture, Technology and Sciences, Allahabad, 211007, India.
| |
Collapse
|
11
|
Lu Y, Hu X, Nie T, Yang X, Li C, You X. Strategies for Rapid Identification of Acinetobacter baumannii Membrane Proteins and Polymyxin B's Effects. Front Cell Infect Microbiol 2021; 11:734578. [PMID: 34621692 PMCID: PMC8490878 DOI: 10.3389/fcimb.2021.734578] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/01/2021] [Accepted: 08/30/2021] [Indexed: 11/13/2022] Open
Abstract
Acinetobacter baumannii, especially multidrug resistant Acinetobacter baumannii, is a notable source of pressure in the areas of public health and antibiotic development. To overcome this problem, attention has been focused on membrane proteins. Different digestion methods and extraction detergents were examined for membrane proteome sample preparation, and label-free quantitative and targeted proteome analyses of the polymyxin B-induced Acinetobacter baumannii ATCC 19606 membrane proteome were performed based on nano LC-MS/MS. Ultracentrifugation of proteins at a speed of 150,000×g, digestion by trypsin, filter-aided sample preparation, and detergents such as lauryldimethylamine-N-oxide were proved as a fast and effective way for identification of membrane proteome by nano LC-MS/MS. Upon treatment with polymyxin B, expression levels of 15 proteins related to membrane structure, transporters, cell surface, and periplasmic space were found to be significantly changed. Furthermore, targeted proteome was also used to confirm these changes. A relatively rapid membrane proteome preparation method was developed, and a more comprehensive view of changes in the Acinetobacter baumannii membrane proteome under polymyxin B pressure was obtained.
Collapse
Affiliation(s)
- Yun Lu
- Beijing Key Laboratory of Antimicrobial Agents, Institute of Medicinal Biotechnology, Chinese Academy of Medical Sciences and Peking Union Medical College, Beijing, China
| | - Xinxin Hu
- Beijing Key Laboratory of Antimicrobial Agents, Institute of Medicinal Biotechnology, Chinese Academy of Medical Sciences and Peking Union Medical College, Beijing, China
| | - Tongying Nie
- Beijing Key Laboratory of Antimicrobial Agents, Institute of Medicinal Biotechnology, Chinese Academy of Medical Sciences and Peking Union Medical College, Beijing, China
| | - Xinyi Yang
- Beijing Key Laboratory of Antimicrobial Agents, Institute of Medicinal Biotechnology, Chinese Academy of Medical Sciences and Peking Union Medical College, Beijing, China
| | - Congran Li
- Beijing Key Laboratory of Antimicrobial Agents, Institute of Medicinal Biotechnology, Chinese Academy of Medical Sciences and Peking Union Medical College, Beijing, China
| | - Xuefu You
- Beijing Key Laboratory of Antimicrobial Agents, Institute of Medicinal Biotechnology, Chinese Academy of Medical Sciences and Peking Union Medical College, Beijing, China
| |
Collapse
|
12
|
Impact of the Resistance Responses to Stress Conditions Encountered in Food and Food Processing Environments on the Virulence and Growth Fitness of Non-Typhoidal Salmonellae. Foods 2021; 10:foods10030617. [PMID: 33799446 PMCID: PMC8001757 DOI: 10.3390/foods10030617] [Citation(s) in RCA: 29] [Impact Index Per Article: 9.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/05/2021] [Revised: 02/24/2021] [Accepted: 03/10/2021] [Indexed: 01/22/2023] Open
Abstract
The success of Salmonella as a foodborne pathogen can probably be attributed to two major features: its remarkable genetic diversity and its extraordinary ability to adapt. Salmonella cells can survive in harsh environments, successfully compete for nutrients, and cause disease once inside the host. Furthermore, they are capable of rapidly reprogramming their metabolism, evolving in a short time from a stress-resistance mode to a growth or virulent mode, or even to express stress resistance and virulence factors at the same time if needed, thanks to a complex and fine-tuned regulatory network. It is nevertheless generally acknowledged that the development of stress resistance usually has a fitness cost for bacterial cells and that induction of stress resistance responses to certain agents can trigger changes in Salmonella virulence. In this review, we summarize and discuss current knowledge concerning the effects that the development of resistance responses to stress conditions encountered in food and food processing environments (including acid, osmotic and oxidative stress, starvation, modified atmospheres, detergents and disinfectants, chilling, heat, and non-thermal technologies) exerts on different aspects of the physiology of non-typhoidal Salmonellae, with special emphasis on virulence and growth fitness.
Collapse
|
13
|
Shome A, Sarkhel R, Apoorva S, Nair SS, Chauhan TKS, Bhure SK, Mahawar M. Role of protein repair enzymes in oxidative stress survival and virulence of Salmonella. ANN MICROBIOL 2020. [DOI: 10.1186/s13213-020-01597-2] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/18/2023] Open
Abstract
Abstract
Purpose
Proteins are the principal biomolecules in bacteria that are affected by the oxidants produced by the phagocytic cells. Most of the protein damage is irreparable though few unfolded proteins and covalently modified amino acids can be repaired by chaperones and repair enzymes respectively. This study reviews the three protein repair enzymes, protein l-isoaspartyl O-methyl transferase (PIMT), peptidyl proline cis-trans isomerase (PPIase), and methionine sulfoxide reductase (MSR).
Methods
Published articles regarding protein repair enzymes were collected from Google Scholar and PubMed. The information obtained from the research articles was analyzed and categorized into general information about the enzyme, mechanism of action, and role played by the enzymes in bacteria. Special emphasis was given to the importance of these enzymes in Salmonella Typhimurium.
Results
Protein repair is the direct and energetically preferred way of replenishing the cellular protein pool without translational synthesis. Under the oxidative stress mounted by the host during the infection, protein repair becomes very crucial for the survival of the bacterial pathogens. Only a few covalent modifications of amino acids are reversible by the protein repair enzymes, and they are highly specific in activity. Deletion mutants of these enzymes in different bacteria revealed their importance in the virulence and oxidative stress survival.
Conclusion
PIMT repairs isoaspartate residues, PPiase catalyzes the conversion of cis-trans forms of proline residues, while MSR repairs oxidized methionine (Met) residues in the proteins. These repair enzymes maintain the activities of the target protein(s), thus aid in bacterial survival and virulence. The interventions which can interfere with this mechanism could be used for the development of novel therapeutics.
Collapse
|
14
|
Jia M, Wu B, Yang Z, Chen C, Zhao M, Hou X, Niu X, Jin C, Hu Y. Conformational Dynamics of the Periplasmic Chaperone SurA. Biochemistry 2020; 59:3235-3246. [PMID: 32786408 DOI: 10.1021/acs.biochem.0c00507] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/30/2022]
Abstract
The periplasmic protein SurA is the primary chaperone involved in the biogenesis of bacterial outer membrane proteins and is a potential antibacterial drug target. The three-dimensional structure of SurA can be divided into three parts, a core module formed by the N- and C-terminal regions and two peptidyl-prolyl isomerase (PPIase) domains, P1 and P2. Despite the determination of the structures of several SurA-peptide complexes, the functional mechanism of this chaperone remains elusive and the roles of the two PPIase domains are yet unclear. Herein, we characterize the conformational dynamics of SurA by using solution nuclear magnetic resonance and single-molecule fluorescence resonance energy transfer methods. We demonstrate a "closed-to-open" structural transition of the P1 domain that is correlated with both chaperone activity and peptide binding and show that the flexible P2 domain can also occupy conformations that closely contact the NC core module. Our results offer a structural basis for the counteracting roles of the two PPIase domains in regulating the SurA chaperone activity.
Collapse
Affiliation(s)
- Moye Jia
- Beijing Nuclear Magnetic Resonance Center, College of Chemistry and Molecular Engineering, Peking University, Beijing 100871, China
| | - Bo Wu
- School of Life Sciences, Beijing Advanced Innovation Center for Structural Biology, Beijing Frontier Research Center for Biological Structure, Tsinghua University, Beijing 100084, China
| | - Ziyu Yang
- Beijing National Laboratory for Molecular Sciences, Peking University, Beijing 100871, China.,MOE Key Laboratory of Bioorganic Chemistry and Molecular Engineering, College of Chemistry and Molecular Engineering, Peking University, Beijing 100871, China
| | - Chunlai Chen
- School of Life Sciences, Beijing Advanced Innovation Center for Structural Biology, Beijing Frontier Research Center for Biological Structure, Tsinghua University, Beijing 100084, China
| | - Meiping Zhao
- Beijing National Laboratory for Molecular Sciences, Peking University, Beijing 100871, China.,MOE Key Laboratory of Bioorganic Chemistry and Molecular Engineering, College of Chemistry and Molecular Engineering, Peking University, Beijing 100871, China
| | - Xianhui Hou
- Beijing Nuclear Magnetic Resonance Center, College of Chemistry and Molecular Engineering, Peking University, Beijing 100871, China
| | - Xiaogang Niu
- Beijing Nuclear Magnetic Resonance Center, College of Chemistry and Molecular Engineering, Peking University, Beijing 100871, China
| | - Changwen Jin
- Beijing Nuclear Magnetic Resonance Center, College of Chemistry and Molecular Engineering, Peking University, Beijing 100871, China.,Beijing National Laboratory for Molecular Sciences, Peking University, Beijing 100871, China
| | - Yunfei Hu
- State Key Laboratory of Magnetic Resonance and Atomic and Molecular Physics, Wuhan National Laboratory for Optoelectronics, National Center for Magnetic Resonance in Wuhan, Key Laboratory of Magnetic Resonance in Biological Systems, Innovation Academy for Precision Measurement Science and Technology, CAS, Wuhan 430071, China.,University of Chinese Academy of Sciences, Beijing 100049, China
| |
Collapse
|
15
|
Wu X, Zhou H, Li L, Wang E, Zhou X, Gu Y, Wu X, Shen L, Zeng W. Whole Genome Sequencing and Comparative Genomic Analyses of Lysinibacillus pakistanensis LZH-9, a Halotolerant Strain with Excellent COD Removal Capability. Microorganisms 2020; 8:microorganisms8050716. [PMID: 32408484 PMCID: PMC7284689 DOI: 10.3390/microorganisms8050716] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/14/2020] [Revised: 05/07/2020] [Accepted: 05/08/2020] [Indexed: 11/26/2022] Open
Abstract
Halotolerant microorganisms are promising in bio-treatment of hypersaline industrial wastewater. Four halotolerant bacteria strains were isolated from wastewater treatment plant, of which a strain LZH-9 could grow in the presence of up to 14% (w/v) NaCl, and it removed 81.9% chemical oxygen demand (COD) at 96 h after optimization. Whole genome sequencing of Lysinibacillus pakistanensis LZH-9 and comparative genomic analysis revealed metabolic versatility of different species of Lysinibacillus, and abundant genes involved in xenobiotics biodegradation, resistance to toxic compound, and salinity were found in all tested species of Lysinibacillus, in which Horizontal Gene Transfer (HGT) contributed to the acquisition of many important properties of Lysinibacillus spp. such as toxic compound resistance and osmotic stress resistance as revealed by phylogenetic analyses. Besides, genome wide positive selection analyses revealed seven genes that contained adaptive mutations in Lysinibacillus spp., most of which were multifunctional. Further expression assessment with Codon Adaption Index (CAI) also reflected the high metabolic rate of L. pakistanensis to digest potential carbon or nitrogen sources in organic contaminants, which was closely linked with efficient COD removal ability of strain LZH-9. The high COD removal efficiency and halotolerance as well as genomic evidences suggested that L. pakistanensis LZH-9 was promising in treating hypersaline industrial wastewater.
Collapse
Affiliation(s)
- Xueling Wu
- School of Minerals Processing and Bioengineering, Central South University, Changsha 410083, China; (X.W.); (H.Z.); (L.L.); (E.W.); (X.Z.); (Y.G.); (X.W.); (L.S.)
- Key Laboratory of Biometallurgy of Ministry of Education, Central South University, Changsha 410083, China
| | - Han Zhou
- School of Minerals Processing and Bioengineering, Central South University, Changsha 410083, China; (X.W.); (H.Z.); (L.L.); (E.W.); (X.Z.); (Y.G.); (X.W.); (L.S.)
| | - Liangzhi Li
- School of Minerals Processing and Bioengineering, Central South University, Changsha 410083, China; (X.W.); (H.Z.); (L.L.); (E.W.); (X.Z.); (Y.G.); (X.W.); (L.S.)
| | - Enhui Wang
- School of Minerals Processing and Bioengineering, Central South University, Changsha 410083, China; (X.W.); (H.Z.); (L.L.); (E.W.); (X.Z.); (Y.G.); (X.W.); (L.S.)
| | - Xiangyu Zhou
- School of Minerals Processing and Bioengineering, Central South University, Changsha 410083, China; (X.W.); (H.Z.); (L.L.); (E.W.); (X.Z.); (Y.G.); (X.W.); (L.S.)
| | - Yichao Gu
- School of Minerals Processing and Bioengineering, Central South University, Changsha 410083, China; (X.W.); (H.Z.); (L.L.); (E.W.); (X.Z.); (Y.G.); (X.W.); (L.S.)
| | - Xiaoyan Wu
- School of Minerals Processing and Bioengineering, Central South University, Changsha 410083, China; (X.W.); (H.Z.); (L.L.); (E.W.); (X.Z.); (Y.G.); (X.W.); (L.S.)
| | - Li Shen
- School of Minerals Processing and Bioengineering, Central South University, Changsha 410083, China; (X.W.); (H.Z.); (L.L.); (E.W.); (X.Z.); (Y.G.); (X.W.); (L.S.)
- Key Laboratory of Biometallurgy of Ministry of Education, Central South University, Changsha 410083, China
| | - Weimin Zeng
- School of Minerals Processing and Bioengineering, Central South University, Changsha 410083, China; (X.W.); (H.Z.); (L.L.); (E.W.); (X.Z.); (Y.G.); (X.W.); (L.S.)
- Key Laboratory of Biometallurgy of Ministry of Education, Central South University, Changsha 410083, China
- Correspondence: ; Tel.: +86-0731-88877472
| |
Collapse
|
16
|
Calabrese AN, Schiffrin B, Watson M, Karamanos TK, Walko M, Humes JR, Horne JE, White P, Wilson AJ, Kalli AC, Tuma R, Ashcroft AE, Brockwell DJ, Radford SE. Inter-domain dynamics in the chaperone SurA and multi-site binding to its outer membrane protein clients. Nat Commun 2020; 11:2155. [PMID: 32358557 PMCID: PMC7195389 DOI: 10.1038/s41467-020-15702-1] [Citation(s) in RCA: 36] [Impact Index Per Article: 9.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/24/2019] [Accepted: 03/18/2020] [Indexed: 01/11/2023] Open
Abstract
The periplasmic chaperone SurA plays a key role in outer membrane protein (OMP) biogenesis. E. coli SurA comprises a core domain and two peptidylprolyl isomerase domains (P1 and P2), but its mechanisms of client binding and chaperone function have remained unclear. Here, we use chemical cross-linking, hydrogen-deuterium exchange mass spectrometry, single-molecule FRET and molecular dynamics simulations to map the client binding site(s) on SurA and interrogate the role of conformational dynamics in OMP recognition. We demonstrate that SurA samples an array of conformations in solution in which P2 primarily lies closer to the core/P1 domains than suggested in the SurA crystal structure. OMP binding sites are located primarily in the core domain, and OMP binding results in conformational changes between the core/P1 domains. Together, the results suggest that unfolded OMP substrates bind in a cradle formed between the SurA domains, with structural flexibility between domains assisting OMP recognition, binding and release.
Collapse
Affiliation(s)
- Antonio N Calabrese
- Astbury Centre for Structural Molecular Biology, School of Molecular and Cellular Biology, Faculty of Biological Sciences, University of Leeds, Leeds, LS2 9JT, UK
| | - Bob Schiffrin
- Astbury Centre for Structural Molecular Biology, School of Molecular and Cellular Biology, Faculty of Biological Sciences, University of Leeds, Leeds, LS2 9JT, UK
| | - Matthew Watson
- Astbury Centre for Structural Molecular Biology, School of Molecular and Cellular Biology, Faculty of Biological Sciences, University of Leeds, Leeds, LS2 9JT, UK
| | - Theodoros K Karamanos
- Astbury Centre for Structural Molecular Biology, School of Molecular and Cellular Biology, Faculty of Biological Sciences, University of Leeds, Leeds, LS2 9JT, UK
- National Institute of Diabetes and Digestive and Kidney Diseases, National Institutes of Health, Bethesda, MD, 20892, USA
| | - Martin Walko
- Astbury Centre for Structural Molecular Biology, School of Molecular and Cellular Biology, Faculty of Biological Sciences, University of Leeds, Leeds, LS2 9JT, UK
- Astbury Centre for Structural Molecular Biology, School of Chemistry, University of Leeds, Leeds, LS2 9JT, UK
| | - Julia R Humes
- Astbury Centre for Structural Molecular Biology, School of Molecular and Cellular Biology, Faculty of Biological Sciences, University of Leeds, Leeds, LS2 9JT, UK
| | - Jim E Horne
- Astbury Centre for Structural Molecular Biology, School of Molecular and Cellular Biology, Faculty of Biological Sciences, University of Leeds, Leeds, LS2 9JT, UK
| | - Paul White
- Astbury Centre for Structural Molecular Biology, School of Molecular and Cellular Biology, Faculty of Biological Sciences, University of Leeds, Leeds, LS2 9JT, UK
| | - Andrew J Wilson
- Astbury Centre for Structural Molecular Biology, School of Molecular and Cellular Biology, Faculty of Biological Sciences, University of Leeds, Leeds, LS2 9JT, UK
- Astbury Centre for Structural Molecular Biology, School of Chemistry, University of Leeds, Leeds, LS2 9JT, UK
| | - Antreas C Kalli
- Astbury Centre for Structural Molecular Biology and School of Medicine, University of Leeds, Leeds, LS2 9JT, UK
| | - Roman Tuma
- Astbury Centre for Structural Molecular Biology, School of Molecular and Cellular Biology, Faculty of Biological Sciences, University of Leeds, Leeds, LS2 9JT, UK
- Faculty of Science, University of South Bohemia, Ceske Budejovice, Czech Republic
| | - Alison E Ashcroft
- Astbury Centre for Structural Molecular Biology, School of Molecular and Cellular Biology, Faculty of Biological Sciences, University of Leeds, Leeds, LS2 9JT, UK
| | - David J Brockwell
- Astbury Centre for Structural Molecular Biology, School of Molecular and Cellular Biology, Faculty of Biological Sciences, University of Leeds, Leeds, LS2 9JT, UK
| | - Sheena E Radford
- Astbury Centre for Structural Molecular Biology, School of Molecular and Cellular Biology, Faculty of Biological Sciences, University of Leeds, Leeds, LS2 9JT, UK.
| |
Collapse
|
17
|
He YU, Wang S, Yin X, Sun F, He B, Liu X. Comparison of Extracellular Proteins from Virulent and Avirulent Vibrio parahaemolyticus Strains To Identify Potential Virulence Factors. J Food Prot 2020; 83:155-162. [PMID: 31860395 DOI: 10.4315/0362-028x.jfp-19-188] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/14/2022]
Abstract
Vibrio parahaemolyticus is a leading seafood-borne pathogen that causes gastroenteritis, septicemia, and serious wound infections due to the actions of virulence-associated proteins. We compared the extracellular proteins of nonvirulent JHY20 and virulent ATCC 33847 V. parahaemolyticus reference strains. Eighteen extracellular proteins were identified from secretory profiles, and 11 (68.75%) of the 16 proteins in ATCC 33847 are associated with virulence and/or protection against adverse conditions: trigger factor, chaperone SurA, aspartate-semialdehyde dehydrogenase, 4-hydroxy-3-methylbut-2-en-1-yl diphosphate synthase, glutamate 5-kinase, alanine dehydrogenase, glyceraldehyde-3-phosphate dehydrogenase, outer membrane protein OmpV, ribosome-associated inhibitor A, chaperone protein Skp, and universal stress protein. Two nontoxic-related proteins, amino acid ABC transporter substrate-binding protein and an uncharacterized protein, were identified in JHY20. The results provide a theoretical basis for supporting safety risk assessment of aquatic foods, illuminate the pathogenic mechanisms of V. parahaemolyticus, and assist the identification of novel vaccine candidates for foodborne pathogens.
Collapse
Affiliation(s)
- Y U He
- College of Food (Biotechnology) Engineering.,Key Construction Laboratory of Food Resources Development and the Quality Safety, Xuzhou University of Technology, Jiangsu, Xuzhou 221018, People's Republic of China
| | - Shuai Wang
- College of Food (Biotechnology) Engineering.,Key Construction Laboratory of Food Resources Development and the Quality Safety, Xuzhou University of Technology, Jiangsu, Xuzhou 221018, People's Republic of China
| | | | - Fengjiao Sun
- Logistics & Security Department, Shanghai Civil Aviation College, Shanghai 201300, People's Republic of China
| | - Bin He
- Environment Monitoring Station, Zaozhuang Municipal Bureau of Ecology and Environment, Shandong 277100, People's Republic of China
| | - Xiao Liu
- Henan Key Laboratory of Cold Chain Food Quality and Safety Control, Zhengzhou University of Light Industry, Zhengzhou 450001, People's Republic of China
| |
Collapse
|
18
|
Ünal CM, Karagöz MS, Berges M, Priebe C, Borrero de Acuña JM, Wissing J, Jänsch L, Jahn D, Steinert M. Pleiotropic Clostridioides difficile Cyclophilin PpiB Controls Cysteine-Tolerance, Toxin Production, the Central Metabolism and Multiple Stress Responses. Front Pharmacol 2019; 10:340. [PMID: 31024308 PMCID: PMC6459899 DOI: 10.3389/fphar.2019.00340] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/04/2018] [Accepted: 03/19/2019] [Indexed: 01/05/2023] Open
Abstract
The Gram-positive pathogen Clostridioides difficile is the main bacterial agent of nosocomial antibiotic associated diarrhea. Bacterial peptidyl-prolyl-cis/trans-isomerases (PPIases) are well established modulators of virulence that influence the outcome of human pathologies during infections. Here, we present the first interactomic network of the sole cyclophilin-type PPIase of C. difficile (CdPpiB) and show that it has diverse interaction partners including major enzymes of the amino acid-dependent energy (LdhA, EtfAB, Had, Acd) and the glucose-derived (Fba, GapA, Pfo, Pyk, Pyc) central metabolism. Proteins of the general (UspA), oxidative (Rbr1,2,3, Dsr), alkaline (YloU, YphY) and cold shock (CspB) response were found bound to CdPpiB. The transcriptional (Lrp), translational (InfC, RFF) and folding (GroS, DnaK) control proteins were also found attached. For a crucial enzyme of cysteine metabolism, O-acetylserine sulfhydrylase (CysK), the global transcription regulator Lrp and the flagellar subunit FliC, these interactions were independently confirmed using a bacterial two hybrid system. The active site residues F50, F109, and F110 of CdPpiB were shown to be important for the interaction with the residue P87 of Lrp. CysK activity after heat denaturation was restored by interaction with CdPpiB. In accordance, tolerance toward cell wall stress caused by the exposure to amoxicillin was reduced. In the absence of CdPpiB, C. difficile was more susceptible toward L-cysteine. At the same time, the cysteine-mediated suppression of toxin production ceased resulting in higher cytotoxicity. In summary, the cyclophilin-type PPIase of C. difficile (CdPpiB) coordinates major cellular processes via its interaction with major regulators of transcription, translation, protein folding, stress response and the central metabolism.
Collapse
Affiliation(s)
- Can Murat Ünal
- Institut für Mikrobiologie, Technische Universität Braunschweig, Braunschweig, Germany.,Moleküler Biyoteknoloji Bölümü, Türk-Alman Üniversitesi, Istanbul, Turkey
| | | | - Mareike Berges
- Institut für Mikrobiologie, Technische Universität Braunschweig, Braunschweig, Germany.,Braunschweig Integrated Centre of Systems Biology, Braunschweig, Germany
| | - Christina Priebe
- Institut für Mikrobiologie, Technische Universität Braunschweig, Braunschweig, Germany
| | | | - Josef Wissing
- Braunschweig Integrated Centre of Systems Biology, Braunschweig, Germany.,Cellular Proteomics Research, Helmholtz Centre for Infection Research, Braunschweig, Germany
| | - Lothar Jänsch
- Braunschweig Integrated Centre of Systems Biology, Braunschweig, Germany.,Cellular Proteomics Research, Helmholtz Centre for Infection Research, Braunschweig, Germany
| | - Dieter Jahn
- Institut für Mikrobiologie, Technische Universität Braunschweig, Braunschweig, Germany.,Braunschweig Integrated Centre of Systems Biology, Braunschweig, Germany
| | - Michael Steinert
- Institut für Mikrobiologie, Technische Universität Braunschweig, Braunschweig, Germany.,Braunschweig Integrated Centre of Systems Biology, Braunschweig, Germany.,Helmholtz Centre for Infection Research, Braunschweig, Germany
| |
Collapse
|
19
|
Abstract
The biogenesis of periplasmic and outer membrane proteins (OMPs) in Escherichia coli is assisted by a variety of processes that help with their folding and transport to their final destination in the cellular envelope. Chaperones are macromolecules, usually proteins, that facilitate the folding of proteins or prevent their aggregation without becoming part of the protein's final structure. Because chaperones often bind to folding intermediates, they often (but not always) act to slow protein folding. Protein folding catalysts, on the other hand, act to accelerate specific steps in the protein folding pathway, including disulfide bond formation and peptidyl prolyl isomerization. This review is primarily concerned with E. coli and Salmonella periplasmic and cellular envelope chaperones; it also discusses periplasmic proline isomerization.
Collapse
|
20
|
Humes JR, Schiffrin B, Calabrese AN, Higgins AJ, Westhead DR, Brockwell DJ, Radford SE. The Role of SurA PPIase Domains in Preventing Aggregation of the Outer-Membrane Proteins tOmpA and OmpT. J Mol Biol 2019; 431:1267-1283. [PMID: 30716334 DOI: 10.1016/j.jmb.2019.01.032] [Citation(s) in RCA: 8] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/02/2018] [Revised: 01/22/2019] [Accepted: 01/25/2019] [Indexed: 10/27/2022]
Abstract
SurA is a conserved ATP-independent periplasmic chaperone involved in the biogenesis of outer-membrane proteins (OMPs). Escherichia coli SurA has a core domain and two peptidylprolyl isomerase (PPIase) domains, the role(s) of which remain unresolved. Here we show that while SurA homologues in early proteobacteria typically contain one or no PPIase domains, the presence of two PPIase domains is common in SurA in later proteobacteria, implying an evolutionary advantage for this domain architecture. Bioinformatics analysis of >350,000 OMP sequences showed that their length, hydrophobicity and aggregation propensity are similar across the proteobacterial classes, ruling out a simple correlation between SurA domain architecture and these properties of OMP sequences. To investigate the role of the PPIase domains in SurA activity, we deleted one or both PPIase domains from E.coli SurA and investigated the ability of the resulting proteins to bind and prevent the aggregation of tOmpA (19 kDa) and OmpT (33 kDa). The results show that wild-type SurA inhibits the aggregation of both OMPs, as do the cytoplasmic OMP chaperones trigger factor and SecB. However, while the ability of SurA to bind and prevent tOmpA aggregation does not depend on its PPIase domains, deletion of even a single PPIase domain ablates the ability of SurA to prevent OmpT aggregation. The results demonstrate that the core domain of SurA endows its generic chaperone ability, while the presence of PPIase domains enhances its chaperone activity for specific OMPs, suggesting one reason for the conservation of multiple PPIase domains in SurA in proteobacteria.
Collapse
Affiliation(s)
- Julia R Humes
- Astbury Centre for Structural Molecular Biology, School of Molecular and Cellular Biology, Faculty of Biological Sciences, University of Leeds, Leeds LS2 9JT, UK
| | - Bob Schiffrin
- Astbury Centre for Structural Molecular Biology, School of Molecular and Cellular Biology, Faculty of Biological Sciences, University of Leeds, Leeds LS2 9JT, UK
| | - Antonio N Calabrese
- Astbury Centre for Structural Molecular Biology, School of Molecular and Cellular Biology, Faculty of Biological Sciences, University of Leeds, Leeds LS2 9JT, UK
| | - Anna J Higgins
- Astbury Centre for Structural Molecular Biology, School of Molecular and Cellular Biology, Faculty of Biological Sciences, University of Leeds, Leeds LS2 9JT, UK
| | - David R Westhead
- Astbury Centre for Structural Molecular Biology, School of Molecular and Cellular Biology, Faculty of Biological Sciences, University of Leeds, Leeds LS2 9JT, UK
| | - David J Brockwell
- Astbury Centre for Structural Molecular Biology, School of Molecular and Cellular Biology, Faculty of Biological Sciences, University of Leeds, Leeds LS2 9JT, UK.
| | - Sheena E Radford
- Astbury Centre for Structural Molecular Biology, School of Molecular and Cellular Biology, Faculty of Biological Sciences, University of Leeds, Leeds LS2 9JT, UK.
| |
Collapse
|
21
|
Ünal CM, Berges M, Smit N, Schiene-Fischer C, Priebe C, Strowig T, Jahn D, Steinert M. PrsA2 (CD630_35000) of Clostridioides difficile Is an Active Parvulin-Type PPIase and a Virulence Modulator. Front Microbiol 2018; 9:2913. [PMID: 30564207 PMCID: PMC6288519 DOI: 10.3389/fmicb.2018.02913] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/17/2018] [Accepted: 11/13/2018] [Indexed: 12/18/2022] Open
Abstract
Clostridioides difficile is the main cause for nosocomial antibiotic associated diarrhea and has become a major burden for the health care systems of industrial countries. Its main virulence factors, the small GTPase glycosylating toxins TcdA and TcdB, are extensively studied. In contrast, the contribution of other factors to development and progression of C. difficile infection (CDI) are only insufficiently understood. Many bacterial peptidyl-prolyl-cis/trans-isomerases (PPIases) have been described in the context of virulence. Among them are the parvulin-type PrsA-like PPIases of Gram-positive bacteria. On this basis, we identified CD630_35000 as the PrsA2 homolog in C. difficile and conducted its enzymatic and phenotypic characterization in order to assess its involvement during C. difficile infection. For this purpose, wild type CdPrsA2 and mutant variants carrying amino acid exchanges mainly in the PPIase domain were recombinantly produced. Recombinant CdPrsA2 showed PPIase activity toward the substrate peptide Ala-Xaa-Pro-Phe with a preference for positively charged amino acids preceding the proline residue. Mutation of conserved residues in its active site pocket impaired the enzymatic activity. A PrsA2 deficient mutant was generated in the C. difficile 630Δerm background using the ClosTron technology. Inactivation of prsA2 resulted in a reduced germination rate in response to taurocholic acid, and in a slight increase in resistance to the secondary bile acids LCA and DCA. Interestingly, in the absence of PrsA2 colonization of mice by C. difficile 630 was significantly reduced. We concluded that CdPrsA2 is an active PPIase that acts as a virulence modulator by influencing crucial processes like sporulation, germination and bile acid resistance resulting in attenuated mice colonization.
Collapse
Affiliation(s)
- Can Murat Ünal
- Institut für Mikrobiologie, Technische Universität Braunschweig, Braunschweig, Germany.,Türk-Alman Üniversitesi, Moleküler Biyoteknoloji Bölümü, Istanbul, Turkey
| | - Mareike Berges
- Institut für Mikrobiologie, Technische Universität Braunschweig, Braunschweig, Germany
| | - Nathiana Smit
- Helmholtz-Zentrum für Infektionsforschung, Braunschweig, Germany
| | - Cordelia Schiene-Fischer
- Institut für Biochemie und Biotechnologie, Martin-Luther-Universität Halle-Wittenberg, Halle, Germany
| | - Christina Priebe
- Institut für Mikrobiologie, Technische Universität Braunschweig, Braunschweig, Germany
| | - Till Strowig
- Helmholtz-Zentrum für Infektionsforschung, Braunschweig, Germany
| | - Dieter Jahn
- Institut für Mikrobiologie, Technische Universität Braunschweig, Braunschweig, Germany.,Braunschweig Integrated Centre of Systems Biology, Braunschweig, Germany
| | - Michael Steinert
- Institut für Mikrobiologie, Technische Universität Braunschweig, Braunschweig, Germany.,Helmholtz-Zentrum für Infektionsforschung, Braunschweig, Germany.,Braunschweig Integrated Centre of Systems Biology, Braunschweig, Germany
| |
Collapse
|
22
|
Bell EW, Zheng EJ, Ryno LM. Identification of inhibitors of the E. coli chaperone SurA using in silico and in vitro techniques. Bioorg Med Chem Lett 2018; 28:3540-3548. [PMID: 30301675 DOI: 10.1016/j.bmcl.2018.09.034] [Citation(s) in RCA: 8] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/12/2018] [Accepted: 09/27/2018] [Indexed: 11/15/2022]
Abstract
SurA is a gram-negative, periplasmic chaperone protein involved in the proper folding of outer membrane porins (OMPs), which protect bacteria against toxins in the extracellular environment by selectively regulating the passage of nutrients into the cell. Previous studies demonstrated that deletion of SurA renders bacteria more sensitive to toxins that compromise the integrity of the outer membrane. Inhibitors of SurA will perturb the folding of OMPs, leading to disruption of the outer membrane barrier and making the cell more vulnerable to toxic insults. The discovery of novel SurA inhibitors is therefore of great importance for developing alternative strategies to overcome antibiotic resistance. Our laboratory has screened over 10,000,000 compoundsin silicoby computationally docking these compounds onto the crystal structure of SurA. Through this screen and a screen of fragment compounds (molecular weight less than 250 g/mol), we found twelve commercially readily available candidate compounds that bind to the putative client binding site of SurA. We confirmed binding to SurA by developing and employing a competitive fluorescence anisotropy-based binding assay. Our results show that one of these compounds, Fmoc-β-(2-quinolyl)-d-alanine, binds the client binding site with high micromolar affinity. Using this compound as a lead, we also discovered that Fmoc-l-tryptophan and Fmoc-l-phenylalanine, but not Fmoc-l-tyrosine, bind SurA with similar micromolar affinity. To our knowledge, this is the first report of a competitive fluorescence anisotropy assay developed for the identification of inhibitors of the chaperone SurA, and the identification of three small molecules that bind SurA at its client binding site.
Collapse
Affiliation(s)
- Eric W Bell
- Department of Chemistry and Biochemistry, Oberlin College, 119 Woodland St. A263, Oberlin, OH 44074, United States
| | - Erica J Zheng
- Department of Chemistry and Biochemistry, Oberlin College, 119 Woodland St. A263, Oberlin, OH 44074, United States
| | - Lisa M Ryno
- Department of Chemistry and Biochemistry, Oberlin College, 119 Woodland St. A263, Oberlin, OH 44074, United States.
| |
Collapse
|
23
|
Artier J, da Silva Zandonadi F, de Souza Carvalho FM, Pauletti BA, Leme AFP, Carnielli CM, Selistre‐de‐Araujo HS, Bertolini MC, Ferro JA, Belasque Júnior J, de Oliveira JCF, Novo‐Mansur MTM. Comparative proteomic analysis of Xanthomonas citri ssp. citri periplasmic proteins reveals changes in cellular envelope metabolism during in vitro pathogenicity induction. MOLECULAR PLANT PATHOLOGY 2018; 19:143-157. [PMID: 27798950 PMCID: PMC6638008 DOI: 10.1111/mpp.12507] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/06/2023]
Abstract
Citrus canker is a plant disease caused by Gram-negative bacteria from the genus Xanthomonas. The most virulent species is Xanthomonas citri ssp. citri (XAC), which attacks a wide range of citrus hosts. Differential proteomic analysis of the periplasm-enriched fraction was performed for XAC cells grown in pathogenicity-inducing (XAM-M) and pathogenicity-non-inducing (nutrient broth) media using two-dimensional electrophoresis combined with liquid chromatography-tandem mass spectrometry. Amongst the 40 proteins identified, transglycosylase was detected in a highly abundant spot in XAC cells grown under inducing condition. Additional up-regulated proteins related to cellular envelope metabolism included glucose-1-phosphate thymidylyltransferase, dTDP-4-dehydrorhamnose-3,5-epimerase and peptidyl-prolyl cis-trans-isomerase. Phosphoglucomutase and superoxide dismutase proteins, known to be involved in pathogenicity in other Xanthomonas species or organisms, were also detected. Western blot and quantitative real-time polymerase chain reaction analyses for transglycosylase and superoxide dismutase confirmed that these proteins were up-regulated under inducing condition, consistent with the proteomic results. Multiple spots for the 60-kDa chaperonin and glyceraldehyde-3-phosphate dehydrogenase were identified, suggesting the presence of post-translational modifications. We propose that substantial alterations in cellular envelope metabolism occur during the XAC infectious process, which are related to several aspects, from defence against reactive oxygen species to exopolysaccharide synthesis. Our results provide new candidates for virulence-related proteins, whose abundance correlates with the induction of pathogenicity and virulence genes, such as hrpD6, hrpG, hrpB7, hpa1 and hrpX. The results present new potential targets against XAC to be investigated in further functional studies.
Collapse
Affiliation(s)
- Juliana Artier
- Laboratório de Bioquímica e Biologia Molecular Aplicada, Departamento de Genética e EvoluçãoUniversidade Federal de São Carlos, UFSCarSão CarlosSP13565‐905Brazil
| | - Flávia da Silva Zandonadi
- Laboratório de Bioquímica e Biologia Molecular Aplicada, Departamento de Genética e EvoluçãoUniversidade Federal de São Carlos, UFSCarSão CarlosSP13565‐905Brazil
| | - Flávia Maria de Souza Carvalho
- Departamento de Tecnologia, Faculdade de Ciências Agrárias e Veterinárias de Jaboticabal, UNESPUniversidade Estadual PaulistaJaboticabalSP14884‐900Brazil
| | - Bianca Alves Pauletti
- LNBio, CNPEMLaboratório de Espectrometria de Massas, Laboratório Nacional de BiociênciasCampinasSP13083‐970Brazil
| | - Adriana Franco Paes Leme
- LNBio, CNPEMLaboratório de Espectrometria de Massas, Laboratório Nacional de BiociênciasCampinasSP13083‐970Brazil
| | - Carolina Moretto Carnielli
- Laboratório de Bioquímica e Biologia Molecular Aplicada, Departamento de Genética e EvoluçãoUniversidade Federal de São Carlos, UFSCarSão CarlosSP13565‐905Brazil
| | | | - Maria Célia Bertolini
- Departamento de Bioquímica e Tecnologia Química, Instituto de Química, UNESPUniversidade Estadual PaulistaAraraquaraSP14800‐060Brazil
| | - Jesus Aparecido Ferro
- Departamento de Tecnologia, Faculdade de Ciências Agrárias e Veterinárias de Jaboticabal, UNESPUniversidade Estadual PaulistaJaboticabalSP14884‐900Brazil
| | - José Belasque Júnior
- Departamento de Fitopatologia e Nematologia, Escola Superior de Agricultura ‘Luiz de Queiroz’Universidade de São PauloPiracicabaSP13418‐900Brazil
| | - Julio Cezar Franco de Oliveira
- Laboratório de Interações Microbianas, Departamento de Ciências BiológicasUniversidade Federal de São Paulo, UNIFESPDiademaSP09913‐030Brazil
| | - Maria Teresa Marques Novo‐Mansur
- Laboratório de Bioquímica e Biologia Molecular Aplicada, Departamento de Genética e EvoluçãoUniversidade Federal de São Carlos, UFSCarSão CarlosSP13565‐905Brazil
| |
Collapse
|
24
|
Schiffrin B, Brockwell DJ, Radford SE. Outer membrane protein folding from an energy landscape perspective. BMC Biol 2017; 15:123. [PMID: 29268734 PMCID: PMC5740924 DOI: 10.1186/s12915-017-0464-5] [Citation(s) in RCA: 52] [Impact Index Per Article: 7.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/04/2023] Open
Abstract
The cell envelope is essential for the survival of Gram-negative bacteria. This specialised membrane is densely packed with outer membrane proteins (OMPs), which perform a variety of functions. How OMPs fold into this crowded environment remains an open question. Here, we review current knowledge about OMP folding mechanisms in vitro and discuss how the need to fold to a stable native state has shaped their folding energy landscapes. We also highlight the role of chaperones and the β-barrel assembly machinery (BAM) in assisting OMP folding in vivo and discuss proposed mechanisms by which this fascinating machinery may catalyse OMP folding.
Collapse
Affiliation(s)
- Bob Schiffrin
- Astbury Centre for Structural Molecular Biology, School of Molecular and Cellular Biology, Faculty of Biological Sciences, University of Leeds, Leeds, LS2 9JT, UK
| | - David J Brockwell
- Astbury Centre for Structural Molecular Biology, School of Molecular and Cellular Biology, Faculty of Biological Sciences, University of Leeds, Leeds, LS2 9JT, UK.
| | - Sheena E Radford
- Astbury Centre for Structural Molecular Biology, School of Molecular and Cellular Biology, Faculty of Biological Sciences, University of Leeds, Leeds, LS2 9JT, UK.
| |
Collapse
|
25
|
Vivoli M, Renou J, Chevalier A, Norville IH, Diaz S, Juli C, Atkins H, Holzgrabe U, Renard PY, Sarkar-Tyson M, Harmer NJ. A miniaturized peptidyl-prolyl isomerase enzyme assay. Anal Biochem 2017; 536:59-68. [PMID: 28803887 DOI: 10.1016/j.ab.2017.08.004] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/14/2017] [Revised: 08/04/2017] [Accepted: 08/09/2017] [Indexed: 01/15/2023]
Abstract
Prolyl-peptidyl isomerases (PPIases) are enzymes that are found in all living organisms. They form an essential part of the cellular protein folding homeostasis machinery. PPIases are associated with many important human diseases, e.g. cardiovascular disease, cancer and Alzheimer's. The development of novel PPIase inhibitors has been limited by the lack of a rapid, laboratory-based assay for these enzymes, as their substrates and products are challenging to distinguish. A well described continuous assay, coupled with the hydrolysis of a peptide by chymotrypsin is highly effective, but comparatively slow. To address this, we developed an improved version of the traditional assay using a temperature controlled plate reader. This assay allows semi-automated medium throughput assays in an academic laboratory for 84 samples per day. The assay shows lower errors, with an average Z' of 0.72. We further developed the assay using a fluorogenic peptide-based FRET probe. This provides an extremely sensitive PPIase assay using substrate at 200 nM, which approaches single turnover conditions. The fluorescent probe achieves an excellent quenching efficiency of 98.6%, and initial experiments showed acceptable Z' of 0.31 and 0.30 for cyclophilin A and hFKBP12 respectively. The assays provide an improved toolset for the quantitative, biochemical analysis of PPIases.
Collapse
Affiliation(s)
- Mirella Vivoli
- College of Life and Environmental Sciences, University of Exeter, Exeter EX4 4QD, United Kingdom
| | - Julien Renou
- Normandie Univ, UNIROUEN, CNRS, INSAREOUEN, COBRA, UMR 6014 & FR 3038, 1 rue Tesnière 76000 Rouen, France
| | - Arnaud Chevalier
- Normandie Univ, UNIROUEN, CNRS, INSAREOUEN, COBRA, UMR 6014 & FR 3038, 1 rue Tesnière 76000 Rouen, France
| | - Isobel H Norville
- Defence Science and Technology Laboratory, Porton Down SP4 0JQ, United Kingdom
| | - Suraya Diaz
- College of Life and Environmental Sciences, University of Exeter, Exeter EX4 4QD, United Kingdom
| | - Christina Juli
- Institute of Pharmacy, University of Würzburg, Am Hubland, 970074 Würzburg, Germany
| | - Helen Atkins
- Defence Science and Technology Laboratory, Porton Down SP4 0JQ, United Kingdom
| | - Ulrike Holzgrabe
- Institute of Pharmacy, University of Würzburg, Am Hubland, 970074 Würzburg, Germany
| | - Pierre-Yves Renard
- Normandie Univ, UNIROUEN, CNRS, INSAREOUEN, COBRA, UMR 6014 & FR 3038, 1 rue Tesnière 76000 Rouen, France
| | - Mitali Sarkar-Tyson
- Defence Science and Technology Laboratory, Porton Down SP4 0JQ, United Kingdom; Marshall Centre for Infectious Diseases, School of Pathology and Laboratory Medicine, University of Western Australia, Crawley, WA 6009, Australia
| | - Nicholas J Harmer
- College of Life and Environmental Sciences, University of Exeter, Exeter EX4 4QD, United Kingdom.
| |
Collapse
|
26
|
Dawoud TM, Davis ML, Park SH, Kim SA, Kwon YM, Jarvis N, O’Bryan CA, Shi Z, Crandall PG, Ricke SC. The Potential Link between Thermal Resistance and Virulence in Salmonella: A Review. Front Vet Sci 2017; 4:93. [PMID: 28660201 PMCID: PMC5469892 DOI: 10.3389/fvets.2017.00093] [Citation(s) in RCA: 30] [Impact Index Per Article: 4.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/20/2017] [Accepted: 06/01/2017] [Indexed: 12/19/2022] Open
Abstract
In some animals, the typical body temperature can be higher than humans, for example, 42°C in poultry and 40°C in rabbits which can be a potential thermal stress challenge for pathogens. Even in animals with lower body temperatures, when infection occurs, the immune system may increase body temperature to reduce the chance of survival for pathogens. However, some pathogens can still easily overcome higher body temperatures and/or rise in body temperatures through expression of stress response mechanisms. Salmonella is the causative agent of one of the most prevalent foodborne illnesses, salmonellosis, and can readily survive over a wide range of temperatures due to the efficient expression of the heat (thermal) stress response. Therefore, thermal resistance mechanisms can provide cross protection against other stresses including the non-specific host defenses found within the human body thus increasing pathogenic potential. Understanding the molecular mechanisms associated with thermal responses in Salmonella is crucial in designing and developing more effective or new treatments for reducing and eliminating infection caused by Salmonella that have survived heat stress. In this review, Salmonella thermal resistance is assessed followed by an overview of the thermal stress responses with a focus on gene regulation by sigma factors, heat shock proteins, along with the corresponding thermosensors and their association with virulence expression including a focus on a potential link between heat resistance and potential for infection.
Collapse
Affiliation(s)
- Turki M. Dawoud
- Cell and Molecular Biology Program, University of Arkansas, Fayetteville, AR, United States
- Center for Food Safety, University of Arkansas, Fayetteville, AR, United States
| | - Morgan L. Davis
- Center for Food Safety, University of Arkansas, Fayetteville, AR, United States
- Department of Food Science, University of Arkansas, Fayetteville, AR, United States
| | - Si Hong Park
- Center for Food Safety, University of Arkansas, Fayetteville, AR, United States
- Department of Food Science, University of Arkansas, Fayetteville, AR, United States
| | - Sun Ae Kim
- Center for Food Safety, University of Arkansas, Fayetteville, AR, United States
- Department of Food Science, University of Arkansas, Fayetteville, AR, United States
| | - Young Min Kwon
- Cell and Molecular Biology Program, University of Arkansas, Fayetteville, AR, United States
- Center for Food Safety, University of Arkansas, Fayetteville, AR, United States
- Department of Poultry Science, University of Arkansas, Fayetteville, AR, United States
| | - Nathan Jarvis
- Center for Food Safety, University of Arkansas, Fayetteville, AR, United States
- Department of Food Science, University of Arkansas, Fayetteville, AR, United States
| | - Corliss A. O’Bryan
- Center for Food Safety, University of Arkansas, Fayetteville, AR, United States
- Department of Food Science, University of Arkansas, Fayetteville, AR, United States
| | - Zhaohao Shi
- Center for Food Safety, University of Arkansas, Fayetteville, AR, United States
- Department of Food Science, University of Arkansas, Fayetteville, AR, United States
| | - Philip G. Crandall
- Center for Food Safety, University of Arkansas, Fayetteville, AR, United States
- Department of Food Science, University of Arkansas, Fayetteville, AR, United States
| | - Steven C. Ricke
- Cell and Molecular Biology Program, University of Arkansas, Fayetteville, AR, United States
- Center for Food Safety, University of Arkansas, Fayetteville, AR, United States
- Department of Food Science, University of Arkansas, Fayetteville, AR, United States
| |
Collapse
|
27
|
Cahoon LA, Freitag NE, Prehna G. A structural comparison of Listeria monocytogenes protein chaperones PrsA1 and PrsA2 reveals molecular features required for virulence. Mol Microbiol 2016; 101:42-61. [PMID: 27007641 PMCID: PMC4925323 DOI: 10.1111/mmi.13367] [Citation(s) in RCA: 12] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Accepted: 02/29/2016] [Indexed: 12/26/2022]
Abstract
Listeria monocytogenes is a Gram-positive environmental bacterium that lives within soil but transitions into a pathogen upon contact with a mammalian host. The transition of L. monocytogenes from soil dweller to cytosolic pathogen is dependent upon secreted virulence factors that mediate cell invasion and intracellular growth. PrsA1 and PrsA2 are secreted bacterial lipoprotein chaperones that contribute to the folding of proteins translocated across the bacterial membrane; PrsA2 is required for L. monocytogenes virulence, whereas the function of PrsA1 remains to be determined. We have solved an X-ray crystal structure of PrsA1 and have used this model to guide comparison structure-based mutagenesis studies with PrsA2. Targeted mutagenesis of PrsA2 demonstrates that oligomerization of PrsA2 as well as molecular features of the foldase domain are required for protein secretion and virulence, whereas a functional role was uncovered for PrsA1 in bacterial resistance to alcohol. Interestingly, PrsA2 membrane localization is not required for all PrsA2-dependent activities, suggesting that the lipoprotein retains function when released from the bacterial cell. PrsA chaperones are thus multifaceted proteins with distinct domains adapted to accommodate the functional needs of a diverse array of secreted substrates.
Collapse
Affiliation(s)
- Laty A. Cahoon
- Department of Microbiology and Immunology, University of Illinois at Chicago
| | - Nancy E. Freitag
- Department of Microbiology and Immunology, University of Illinois at Chicago
| | - Gerd Prehna
- Department of Microbiology and Immunology, University of Illinois at Chicago
- Center for Structural Biology Research Resources Center, University of Illinois at Chicago
| |
Collapse
|
28
|
Chen S, Thompson KM, Francis MS. Environmental Regulation of Yersinia Pathophysiology. Front Cell Infect Microbiol 2016; 6:25. [PMID: 26973818 PMCID: PMC4773443 DOI: 10.3389/fcimb.2016.00025] [Citation(s) in RCA: 27] [Impact Index Per Article: 3.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/15/2015] [Accepted: 02/15/2016] [Indexed: 12/26/2022] Open
Abstract
Hallmarks of Yersinia pathogenesis include the ability to form biofilms on surfaces, the ability to establish close contact with eukaryotic target cells and the ability to hijack eukaryotic cell signaling and take over control of strategic cellular processes. Many of these virulence traits are already well-described. However, of equal importance is knowledge of both confined and global regulatory networks that collaborate together to dictate spatial and temporal control of virulence gene expression. This review has the purpose to incorporate historical observations with new discoveries to provide molecular insight into how some of these regulatory mechanisms respond rapidly to environmental flux to govern tight control of virulence gene expression by pathogenic Yersinia.
Collapse
Affiliation(s)
- Shiyun Chen
- Key Laboratory of Special Pathogens and Biosafety, Wuhan Institute of Virology, Chinese Academy of Sciences Wuhan, China
| | - Karl M Thompson
- Department of Microbiology, College of Medicine, Howard University Washington, DC, USA
| | - Matthew S Francis
- Umeå Centre for Microbial Research, Umeå UniversityUmeå, Sweden; Department of Molecular Biology, Umeå UniversityUmeå, Sweden
| |
Collapse
|
29
|
Survival protein A is essential for virulence in Yersinia pestis. Microb Pathog 2016; 92:50-53. [DOI: 10.1016/j.micpath.2015.12.013] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/06/2015] [Revised: 12/18/2015] [Accepted: 12/22/2015] [Indexed: 01/13/2023]
|
30
|
The Activity of Escherichia coli Chaperone SurA Is Regulated by Conformational Changes Involving a Parvulin Domain. J Bacteriol 2016; 198:921-9. [PMID: 26728192 DOI: 10.1128/jb.00889-15] [Citation(s) in RCA: 28] [Impact Index Per Article: 3.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/30/2015] [Accepted: 12/29/2015] [Indexed: 01/10/2023] Open
Abstract
UNLABELLED The periplasmic chaperone SurA is critical for the biogenesis of outer membrane proteins (OMPs) and, thus, the maintenance of membrane integrity in Escherichia coli. The activity of this modular chaperone has been attributed to a core chaperone module, with only minor importance assigned to the two SurA peptidyl-prolyl isomerase (PPIase) domains. In this work, we used synthetic phenotypes and covalent tethering to demonstrate that the activity of SurA is regulated by its PPIase domains and, furthermore, that its activity is correlated with the conformational state of the chaperone. When combined with mutations in the β-barrel assembly machine (BAM), SurA mutations resulting in deletion of the second parvulin domain (P2) inhibit OMP assembly, suggesting that P2 is involved in the regulation of SurA. The first parvulin domain (P1) potentiates this autoinhibition, as mutations that covalently tether the P1 domain to the core chaperone module severely impair OMP assembly. Furthermore, these inhibitory mutations negate the suppression of and biochemically stabilize the protein specified by a well-characterized gain-of-function mutation in P1, demonstrating that SurA cycles between distinct conformational and functional states during the OMP assembly process. IMPORTANCE This work reveals the reversible autoinhibition of the SurA chaperone imposed by a heretofore underappreciated parvulin domain. Many β-barrel-associated outer membrane (OM) virulence factors, including the P-pilus and type I fimbriae, rely on SurA for proper assembly; thus, a mechanistic understanding of SurA function and inhibition may facilitate antibiotic intervention against Gram-negative pathogens, such as uropathogenic Escherichia coli, E. coli O157:H7, Shigella, and Salmonella. In addition, SurA is important for the assembly of critical OM biogenesis factors, such as the lipopolysaccharide (LPS) transport machine, suggesting that specific targeting of SurA may provide a useful means to subvert the OM barrier.
Collapse
|
31
|
Humbert MV, Almonacid Mendoza HL, Jackson AC, Hung MC, Bielecka MK, Heckels JE, Christodoulides M. Vaccine potential of bacterial macrophage infectivity potentiator (MIP)-like peptidyl prolyl cis/trans isomerase (PPIase) proteins. Expert Rev Vaccines 2015; 14:1633-49. [PMID: 26468663 DOI: 10.1586/14760584.2015.1095638] [Citation(s) in RCA: 12] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/18/2023]
Abstract
Peptidyl prolyl cis/trans isomerases (PPIases) are a superfamily of proteins ubiquitously distributed among living organisms, which function primarily to assist the folding and structuring of unfolded and partially folded polypeptide chains and proteins. In this review, we focus specifically on the Macrophage Infectivity Potentiator (MIP)-like PPIases, which are members of the immunophilin family of FK506-binding proteins (FKBP). MIP-like PPIases have accessory roles in virulence and are candidates for inclusion in vaccines protective against both animal and human bacterial pathogens. A structural vaccinology approach obviates any issues over molecular mimicry and potential cross-reactivity with human FKBP proteins and studies with a representative antigen, the Neisseria meningitidis-MIP, support this strategy. Moreover, a dual approach of vaccination and drug targeting could be considered for controlling bacterial infectious diseases of humans and animals.
Collapse
Affiliation(s)
- María Victoria Humbert
- a Neisseria Research, Molecular Microbiology, Academic Unit of Clinical and Experimental Sciences, Sir Henry Wellcome Laboratories , University of Southampton Faculty of Medicine , Southampton , UK
| | - Hannia L Almonacid Mendoza
- a Neisseria Research, Molecular Microbiology, Academic Unit of Clinical and Experimental Sciences, Sir Henry Wellcome Laboratories , University of Southampton Faculty of Medicine , Southampton , UK
| | - Alexandra C Jackson
- a Neisseria Research, Molecular Microbiology, Academic Unit of Clinical and Experimental Sciences, Sir Henry Wellcome Laboratories , University of Southampton Faculty of Medicine , Southampton , UK
| | - Miao-Chiu Hung
- a Neisseria Research, Molecular Microbiology, Academic Unit of Clinical and Experimental Sciences, Sir Henry Wellcome Laboratories , University of Southampton Faculty of Medicine , Southampton , UK
| | - Magdalena K Bielecka
- a Neisseria Research, Molecular Microbiology, Academic Unit of Clinical and Experimental Sciences, Sir Henry Wellcome Laboratories , University of Southampton Faculty of Medicine , Southampton , UK
| | - John E Heckels
- a Neisseria Research, Molecular Microbiology, Academic Unit of Clinical and Experimental Sciences, Sir Henry Wellcome Laboratories , University of Southampton Faculty of Medicine , Southampton , UK
| | - Myron Christodoulides
- a Neisseria Research, Molecular Microbiology, Academic Unit of Clinical and Experimental Sciences, Sir Henry Wellcome Laboratories , University of Southampton Faculty of Medicine , Southampton , UK
| |
Collapse
|
32
|
Single-Domain Peptidyl-Prolyl cis/trans Isomerase FkpA from Corynebacterium glutamicum Improves the Biomass Yield at Increased Growth Temperatures. Appl Environ Microbiol 2015; 81:7839-50. [PMID: 26341203 DOI: 10.1128/aem.02113-15] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/26/2015] [Accepted: 08/30/2015] [Indexed: 12/15/2022] Open
Abstract
Peptidyl-prolyl cis/trans isomerases (PPIases) catalyze the rate-limiting protein folding step at peptidyl bonds preceding proline residues and were found to be involved in several biological processes, including gene expression, signal transduction, and protein secretion. Representative enzymes were found in almost all sequenced genomes, including Corynebacterium glutamicum, a facultative anaerobic Gram-positive and industrial workhorse for the production of amino acids. In C. glutamicum, a predicted single-domain FK-506 (tacrolimus) binding protein (FKBP)-type PPIase (FkpA) is encoded directly downstream of gltA, which encodes citrate synthase (CS). This gene cluster is also present in other Actinobacteria. Here we carried out in vitro and in vivo experiments to study the function and influence of predicted FkpA in C. glutamicum. In vitro, FkpA indeed shows typical PPIase activity with artificial substrates and is inhibited by FK-506. Furthermore, FkpA delays the aggregation of CS, which is also inhibited by FK-506. Surprisingly, FkpA has a positive effect on the activity and temperature range of CS in vitro. Deletion of fkpA causes a 50% reduced biomass yield compared to that of the wild type when grown at 37°C, whereas there is only a 10% reduced biomass yield at the optimal growth temperature of 30°C accompanied by accumulation of 7 mM l-glutamate and 22 mM 2-oxoglutarate. Thus, FkpA may be exploited for improved product formation in biotechnical processes. Comparative transcriptome analysis revealed 69 genes which exhibit ≥2-fold mRNA level changes in C. glutamicum ΔfkpA, giving insight into the transcriptional response upon mild heat stress when FkpA is absent.
Collapse
|
33
|
Zaheer R, Klima CL, McAllister TA. Expeditious screening of candidate proteins for microbial vaccines. J Microbiol Methods 2015; 116:53-9. [PMID: 26149626 DOI: 10.1016/j.mimet.2015.06.018] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/05/2015] [Revised: 06/26/2015] [Accepted: 06/27/2015] [Indexed: 11/18/2022]
Abstract
Advancements in high-throughput "omics" technologies have revolutionized the way vaccine candidates are identified. Now every surface expressed protein that an organism produces can be identified in silico and possibly made available for the rapid development of recombinant/subunit vaccines. However, evaluating the antigenicity of a large number of candidate proteins is an immense challenge, typically requiring cloning of several hundred candidates followed by immunogenicity screening. Here we report the development of a rapid, high-throughput method for screening candidate proteins for vaccines. This method involves utilizing a coupled, cell-free transcription-translation system to screen tagged proteins that are captured at the C-termini using appropriate ligand coated wells in 96 well ELISA plates. The template DNA for the cell-free expression is generated by two sequential PCRs and includes gene coding sequences, promoter, terminator, other necessary cis-acting elements and appropriate tag sequences. The process generates expressible candidate proteins containing two different peptide tags at the N- and the C-termini of the protein molecules. Proteins are screened in parallel for their quantity and immunoreactivity with N-terminal tag antibodies and antisera raised against the pathogen of interest, respectively. Normalization against the total detectable bound protein in the control wells allows for the identification of highly immunoreactive candidates. For this study we selected 30 representatives of >300 potential candidate proteins from Mannheimia haemolytica, a bacterial agent of pneumonia in feedlot cattle for expression with N-terminal Strep-II and C-terminal His(x6)-tag and evaluated their relative immunoreactivities using Strep-tactin-HRP and rabbit antisera generated against M. haemolytica. Using this system we were able to swiftly and quantitatively analyze and rank the suitability of proteins to identify potentially viable vaccine candidates, with the majority of the high ranking candidates being associated with virulence and pathogenicity. The system is adaptable to any bacterial target and presents an alternative to conventional laborious cloning, expression and screening procedures.
Collapse
Affiliation(s)
- Rahat Zaheer
- Lethbridge Research Centre, Agriculture and Agri-Food Canada, Lethbridge, AB T1J 4B1 Canada
| | - Cassidy L Klima
- Lethbridge Research Centre, Agriculture and Agri-Food Canada, Lethbridge, AB T1J 4B1 Canada
| | - Tim A McAllister
- Lethbridge Research Centre, Agriculture and Agri-Food Canada, Lethbridge, AB T1J 4B1 Canada.
| |
Collapse
|
34
|
Microbial peptidyl-prolyl cis/trans isomerases (PPIases): virulence factors and potential alternative drug targets. Microbiol Mol Biol Rev 2015; 78:544-71. [PMID: 25184565 DOI: 10.1128/mmbr.00015-14] [Citation(s) in RCA: 121] [Impact Index Per Article: 13.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/18/2023] Open
Abstract
Initially discovered in the context of immunomodulation, peptidyl-prolyl cis/trans isomerases (PPIases) were soon identified as enzymes catalyzing the rate-limiting protein folding step at peptidyl bonds preceding proline residues. Intense searches revealed that PPIases are a superfamily of proteins consisting of three structurally distinguishable families with representatives in every described species of prokaryote and eukaryote and, recently, even in some giant viruses. Despite the clear-cut enzymatic activity and ubiquitous distribution of PPIases, reports on solely PPIase-dependent biological roles remain scarce. Nevertheless, they have been found to be involved in a plethora of biological processes, such as gene expression, signal transduction, protein secretion, development, and tissue regeneration, underscoring their general importance. Hence, it is not surprising that PPIases have also been identified as virulence-associated proteins. The extent of contribution to virulence is highly variable and dependent on the pleiotropic roles of a single PPIase in the respective pathogen. The main objective of this review is to discuss this variety in virulence-related bacterial and protozoan PPIases as well as the involvement of host PPIases in infectious processes. Moreover, a special focus is given to Legionella pneumophila macrophage infectivity potentiator (Mip) and Mip-like PPIases of other pathogens, as the best-characterized virulence-related representatives of this family. Finally, the potential of PPIases as alternative drug targets and first tangible results are highlighted.
Collapse
|
35
|
Ünal CM, Steinert M. FKBPs in bacterial infections. Biochim Biophys Acta Gen Subj 2014; 1850:2096-102. [PMID: 25529296 DOI: 10.1016/j.bbagen.2014.12.018] [Citation(s) in RCA: 17] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/07/2014] [Revised: 12/11/2014] [Accepted: 12/13/2014] [Indexed: 02/05/2023]
Abstract
BACKGROUND FK506-binding proteins (FKBPs) contain a domain with peptidyl-prolyl-cis/trans-isomerase (PPIase) activity and bind the immunosuppressive drugs FK506 and rapamycin. FKBPs belong to the immunophilin family and are found in eukaryotes and bacteria. SCOPE OF REVIEW In this review we describe two major groups of bacterial virulence-associated FKBPs, the trigger factor and Mip-like PPIases. Moreover, we discuss the contribution of host FKBPs in bacterial infection processes. MAJOR CONCLUSIONS Since PPIases are regarded as alternative antiinfective drug targets we highlight current research strategies utilizing pipecolinic acid and cycloheximide derivatives as well as substrate based inhibitors. GENERAL SIGNIFICANCE The current research strategies suggest a beneficial synergism of drug development and basic research. This article is part of a Special Issue entitled Proline-directed Foldases: Cell Signaling Catalysts and Drug Targets.
Collapse
Affiliation(s)
- Can M Ünal
- Türk-Alman Üniversitesi, Fen Fakültesi, Istanbul, Turkey; Technische Universität Braunschweig, Institut für Mikrobiologie, Braunschweig, Germany
| | - Michael Steinert
- Technische Universität Braunschweig, Institut für Mikrobiologie, Braunschweig, Germany; Helmholtz Centre for Infection Research, Braunschweig, Germany.
| |
Collapse
|
36
|
Jakob RP, Koch JR, Burmann BM, Schmidpeter PAM, Hunkeler M, Hiller S, Schmid FX, Maier T. Dimeric Structure of the Bacterial Extracellular Foldase PrsA. J Biol Chem 2014; 290:3278-92. [PMID: 25525259 DOI: 10.1074/jbc.m114.622910] [Citation(s) in RCA: 34] [Impact Index Per Article: 3.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/17/2022] Open
Abstract
Secretion of proteins into the membrane-cell wall space is essential for cell wall biosynthesis and pathogenicity in Gram-positive bacteria. Folding and maturation of many secreted proteins depend on a single extracellular foldase, the PrsA protein. PrsA is a 30-kDa protein, lipid anchored to the outer leaflet of the cell membrane. The crystal structure of Bacillus subtilis PrsA reveals a central catalytic parvulin-type prolyl isomerase domain, which is inserted into a larger composite NC domain formed by the N- and C-terminal regions. This domain architecture resembles, despite a lack of sequence conservation, both trigger factor, a ribosome-binding bacterial chaperone, and SurA, a periplasmic chaperone in Gram-negative bacteria. Two main structural differences are observed in that the N-terminal arm of PrsA is substantially shortened relative to the trigger factor and SurA and in that PrsA is found to dimerize in a unique fashion via its NC domain. Dimerization leads to a large, bowl-shaped crevice, which might be involved in vivo in protecting substrate proteins from aggregation. NMR experiments reveal a direct, dynamic interaction of both the parvulin and the NC domain with secretion propeptides, which have been implicated in substrate targeting to PrsA.
Collapse
Affiliation(s)
- Roman P Jakob
- From the Biozentrum, Universität Basel, Klingelbergstrasse 50/70, 4056 Basel, Switzerland and
| | - Johanna R Koch
- the Laboratorium für Biochemie and Bayreuther Zentrum für Molekulare Biowissenschaften, Universität Bayreuth, Universitätsstrasse 30, 95440 Bayreuth, Germany
| | - Björn M Burmann
- From the Biozentrum, Universität Basel, Klingelbergstrasse 50/70, 4056 Basel, Switzerland and
| | - Philipp A M Schmidpeter
- the Laboratorium für Biochemie and Bayreuther Zentrum für Molekulare Biowissenschaften, Universität Bayreuth, Universitätsstrasse 30, 95440 Bayreuth, Germany
| | - Moritz Hunkeler
- From the Biozentrum, Universität Basel, Klingelbergstrasse 50/70, 4056 Basel, Switzerland and
| | - Sebastian Hiller
- From the Biozentrum, Universität Basel, Klingelbergstrasse 50/70, 4056 Basel, Switzerland and
| | - Franz X Schmid
- the Laboratorium für Biochemie and Bayreuther Zentrum für Molekulare Biowissenschaften, Universität Bayreuth, Universitätsstrasse 30, 95440 Bayreuth, Germany
| | - Timm Maier
- From the Biozentrum, Universität Basel, Klingelbergstrasse 50/70, 4056 Basel, Switzerland and
| |
Collapse
|
37
|
McMorran LM, Brockwell DJ, Radford SE. Mechanistic studies of the biogenesis and folding of outer membrane proteins in vitro and in vivo: what have we learned to date? Arch Biochem Biophys 2014; 564:265-80. [PMID: 24613287 PMCID: PMC4262575 DOI: 10.1016/j.abb.2014.02.011] [Citation(s) in RCA: 43] [Impact Index Per Article: 4.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/10/2014] [Revised: 02/16/2014] [Accepted: 02/20/2014] [Indexed: 11/17/2022]
Abstract
Research into the mechanisms by which proteins fold into their native structures has been on-going since the work of Anfinsen in the 1960s. Since that time, the folding mechanisms of small, water-soluble proteins have been well characterised. By contrast, progress in understanding the biogenesis and folding mechanisms of integral membrane proteins has lagged significantly because of the need to create a membrane mimetic environment for folding studies in vitro and the difficulties in finding suitable conditions in which reversible folding can be achieved. Improved knowledge of the factors that promote membrane protein folding and disfavour aggregation now allows studies of folding into lipid bilayers in vitro to be performed. Consequently, mechanistic details and structural information about membrane protein folding are now emerging at an ever increasing pace. Using the panoply of methods developed for studies of the folding of water-soluble proteins. This review summarises current knowledge of the mechanisms of outer membrane protein biogenesis and folding into lipid bilayers in vivo and in vitro and discusses the experimental techniques utilised to gain this information. The emerging knowledge is beginning to allow comparisons to be made between the folding of membrane proteins with current understanding of the mechanisms of folding of water-soluble proteins.
Collapse
Affiliation(s)
- Lindsay M McMorran
- Astbury Centre for Structural Molecular Biology, University of Leeds, Leeds LS2 9JT, UK; School of Molecular and Cellular Biology, University of Leeds, Leeds LS2 9JT, UK
| | - David J Brockwell
- Astbury Centre for Structural Molecular Biology, University of Leeds, Leeds LS2 9JT, UK; School of Molecular and Cellular Biology, University of Leeds, Leeds LS2 9JT, UK
| | - Sheena E Radford
- Astbury Centre for Structural Molecular Biology, University of Leeds, Leeds LS2 9JT, UK; School of Molecular and Cellular Biology, University of Leeds, Leeds LS2 9JT, UK.
| |
Collapse
|
38
|
Peptidylprolyl cis–trans isomerases of Legionella pneumophila: virulence, moonlighting and novel therapeutic targets. Biochem Soc Trans 2014; 42:1728-33. [DOI: 10.1042/bst20140202] [Citation(s) in RCA: 14] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/17/2022]
Abstract
Legionella pneumophila, typically a parasite of free-living protozoa, can also replicate in human alveolar macrophages and lung epithelial cells causing Legionnaires’ disease in humans, a severe atypical pneumonia. The pathogen encodes six peptidylprolyl cis–trans isomerases (PPIases), which generally accelerate folding of prolyl peptide bonds, and influence protein folding. PPIases can be divided into three classes, cyclophilins, parvulins and FK506-binding proteins (FKBPs). They contribute to a multitude of cellular functions including bacterial virulence. In the present review, we provide an overview of L. pneumophila PPIases, discussing their known and anticipated functions as well as moonlighting phenomena. By taking the example of the macrophage infectivity potentiator (Mip) of L. pneumophila, we highlight the potential of PPIases as promising drug targets.
Collapse
|
39
|
Expression, purification and characterization of soluble recombinant peptidyl-prolyl cis/trans isomerase from Vibrio anguillarum. Protein Expr Purif 2014; 101:54-60. [DOI: 10.1016/j.pep.2014.06.005] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/22/2014] [Revised: 06/02/2014] [Accepted: 06/05/2014] [Indexed: 11/22/2022]
|
40
|
Herrmann JM, Riemer J. Three approaches to one problem: protein folding in the periplasm, the endoplasmic reticulum, and the intermembrane space. Antioxid Redox Signal 2014; 21:438-56. [PMID: 24483706 DOI: 10.1089/ars.2014.5841] [Citation(s) in RCA: 27] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 11/13/2022]
Abstract
SIGNIFICANCE The bacterial periplasm, the endoplasmic reticulum (ER), and the intermembrane space (IMS) of mitochondria contain dedicated machineries for the incorporation of disulfide bonds into polypeptides, which cooperate with chaperones, proteases, and assembly factors during protein biogenesis. RECENT ADVANCES The mitochondrial disulfide relay was identified only very recently. The current knowledge of the protein folding machinery of the IMS will be described in detail in this review and compared with the "more established" systems of the periplasm and the ER. CRITICAL ISSUES While the disulfide relays of all three compartments adhere to the same principle, the specific designs and functions of these systems differ considerably. In particular, the cooperation with other folding systems makes the situation in each compartment unique. FUTURE DIRECTIONS The biochemical properties of the oxidation machineries are relatively well understood. However, it still remains largely unclear as to how the quality control systems of "oxidizing" compartments orchestrate the activities of oxidoreductases, chaperones, proteases, and signaling molecules to ensure protein homeostasis.
Collapse
Affiliation(s)
- Johannes M Herrmann
- 1 Department of Cell Biology, University of Kaiserslautern , Kaiserslautern, Germany
| | | |
Collapse
|
41
|
Acid stress management by Cronobacter sakazakii. Int J Food Microbiol 2014; 178:21-8. [DOI: 10.1016/j.ijfoodmicro.2014.03.001] [Citation(s) in RCA: 35] [Impact Index Per Article: 3.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/13/2013] [Revised: 02/09/2014] [Accepted: 03/02/2014] [Indexed: 11/24/2022]
|
42
|
Chai Q, Ferrell B, Zhong M, Zhang X, Ye C, Wei Y. Diverse sequences are functional at the C-terminus of the E. coli periplasmic chaperone SurA. Protein Eng Des Sel 2014; 27:111-6. [PMID: 24586054 DOI: 10.1093/protein/gzu003] [Citation(s) in RCA: 9] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/05/2023] Open
Abstract
SurA is a major periplasmic molecular chaperone in Escherichia coli and has been shown to assist the biogenesis of several outer membrane proteins. The C-terminal fragment of SurA folds into a short β-strand, which forms a small three-stranded anti-parallel β-sheet module with the N-terminal β-hairpin. We found that the length of the C-terminal fragment, rather than its exact amino acid composition, had a big impact on SurA function. To investigate the determinant factor of the C-terminal sequence, we created a library of SurA constructs randomized in the last 10 residues. We screened the library and randomly analyzed 19 constructs that displayed SurA activity. The C-termini of these constructs shared little sequence similarity, except that β-strand-forming residues were preferentially enriched. Three SurA constructs were expressed and purified for structural characterization. Circular dichroism and fluorescence spectroscopy analyses revealed that their structures were similar to the structure of the wild-type SurA. Our results suggest that for scaffolding purpose proteins may tolerate various sequences provided certain general requirements such as hydrophobicity and secondary structure propensity are satisfied. Furthermore, the sequence tolerance of SurA at the C-terminus indicates that this area is not likely to be involved in substrate binding.
Collapse
Affiliation(s)
- Qian Chai
- Department of Chemistry, University of Kentucky, 305 Chemistry-Physics Building, Lexington, KY 40506-0055, USA
| | | | | | | | | | | |
Collapse
|
43
|
Folding mechanisms of periplasmic proteins. BIOCHIMICA ET BIOPHYSICA ACTA-MOLECULAR CELL RESEARCH 2013; 1843:1517-28. [PMID: 24239929 DOI: 10.1016/j.bbamcr.2013.10.014] [Citation(s) in RCA: 90] [Impact Index Per Article: 8.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 08/01/2013] [Revised: 10/11/2013] [Accepted: 10/16/2013] [Indexed: 01/03/2023]
Abstract
More than one fifth of the proteins encoded by the genome of Escherichia coli are destined to the bacterial cell envelope. Over the past 20years, the mechanisms by which envelope proteins reach their three-dimensional structure have been intensively studied, leading to the discovery of an intricate network of periplasmic folding helpers whose members have distinct but complementary roles. For instance, the correct assembly of ß-barrel proteins containing disulfide bonds depends both on chaperones like SurA and Skp for transport across the periplasm and on protein folding catalysts like DsbA and DsbC for disulfide bond formation. In this review, we provide an overview of the current knowledge about the complex network of protein folding helpers present in the periplasm of E. coli and highlight the questions that remain unsolved. This article is part of a Special Issue entitled: Protein trafficking and secretion in bacteria. Guest Editors: Anastassios Economou and Ross Dalbey.
Collapse
|
44
|
The activity and specificity of the outer membrane protein chaperone SurA are modulated by a proline isomerase domain. mBio 2013; 4:mBio.00540-13. [PMID: 23943764 PMCID: PMC3747590 DOI: 10.1128/mbio.00540-13] [Citation(s) in RCA: 23] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/28/2022] Open
Abstract
UNLABELLED SurA is a component of the periplasmic chaperone network that plays a central role in biogenesis of integral outer membrane β-barrel proteins (OMPs) in Escherichia coli. Although SurA contains two well-conserved proline isomerase (PPIase) domains, the contribution of these domains to SurA function is unclear. In the present work, we show that defects in OMP assembly caused by mutation of the β-barrel assembly factors BamA or BamB can be corrected by gain-of-function mutations in SurA that map to the first PPIase domain. These mutations apparently bypass the requirement for a stable interaction between SurA and the Bam complex and enhance SurA chaperone activity in vivo despite destabilization of the protein in vitro. Our findings suggest an autoinhibitory mechanism for regulation of SurA chaperone activity through interdomain interactions involving a PPIase domain. We propose a model in which SurA activity is modulated by an interaction between SurA and the Bam complex that alters the substrate specificity of the chaperone. IMPORTANCE The dominant surA mutations described here alter amino acid residues that are highly conserved in eukaryotic homologs of SurA, including Pin 1, the human proline isomerase (PPIase) implicated in Alzheimer's disease and certain cancers. Consequently, a mechanistic description of SurA function may enhance our understanding of clinically important PPIases and their role(s) in disease. In addition, the virulence of Gram-negative bacterial pathogens, such as Salmonella, Shigella, and Escherichia coli O157:H7, is largely dependent on SurA, making this PPIase/chaperone an attractive antibiotic target. Investigating the function of SurA in outer membrane (OM) biogenesis will be useful in the development of novel therapeutic strategies for the disruption of the OM or the processes that are essential for its assembly.
Collapse
|
45
|
Demarcating SurA activities required for outer membrane targeting of Yersinia pseudotuberculosis adhesins. Infect Immun 2013; 81:2296-308. [PMID: 23589578 DOI: 10.1128/iai.01208-12] [Citation(s) in RCA: 17] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/07/2023] Open
Abstract
SurA is a periplasmic protein folding factor involved in chaperoning and trafficking of outer membrane proteins across the Gram-negative bacterial periplasm. In addition, SurA also possesses peptidyl-prolyl cis/trans isomerase activity. We have previously reported that in enteropathogenic Yersinia pseudotuberculosis, SurA is needed for bacterial virulence and envelope integrity. In this study, we investigated the role of SurA in the assembly of important Yersinia adhesins. Using genetic mutation, biochemical characterization, and an in vitro-based bacterial host cell association assay, we confirmed that surface localization of the invasin adhesin is dependent on SurA. As a surA deletion also has some impact on the levels of individual components of the BAM complex in the Yersinia outer membrane, abolished invasin surface assembly could reflect both a direct loss of SurA-dependent periplasmic targeting and a potentially compromised BAM complex assembly platform in the outer membrane. To various degrees, the assembly of two other adhesins, Ail and the pH 6 antigen fibrillum PsaA, also depends on SurA. Consequently, loss of SurA leads to a dramatic reduction in Yersinia attachment to eukaryotic host cells. Genetic complementation of surA deletion mutants indicated a prominent role for SurA chaperone function in outer membrane protein assembly. Significantly, the N terminus of SurA contributed most of this SurA chaperone function. Despite a dominant chaperoning role, it was also evident that SurA isomerization activity did make a modest contribution to this assembly process.
Collapse
|
46
|
Insights into the function and structural flexibility of the periplasmic molecular chaperone SurA. J Bacteriol 2012; 195:1061-7. [PMID: 23275244 DOI: 10.1128/jb.01143-12] [Citation(s) in RCA: 15] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022] Open
Abstract
SurA is the primary periplasmic molecular chaperone that facilitates the folding and assembling of outer membrane proteins (OMPs) in Gram-negative bacteria. Deletion of the surA gene in Escherichia coli leads to a decrease in outer membrane density and an increase in bacterial drug susceptibility. Here, we conducted mutational studies on SurA to identify residues that are critical for function. One mutant, SurA(V37G), significantly reduced the activity of SurA. Further characterization indicated that SurA(V37G) was structurally similar to, but less stable than, the wild-type protein. The loss of activity in SurA(V37G) could be restored through the introduction of a pair of Cys residues and the subsequent formation of a disulfide bond. Inspired by this success, we created three additional SurA constructs, each containing a disulfide bond at different regions of the protein between two rigid secondary structural elements. The formation of disulfide bond in these mutants has no observable detrimental effect on protein activity, indicating that SurA does not undergo large-scale conformational change while performing its function.
Collapse
|
47
|
Misra R. Assembly of the β-Barrel Outer Membrane Proteins in Gram-Negative Bacteria, Mitochondria, and Chloroplasts. ISRN MOLECULAR BIOLOGY 2012; 2012:708203. [PMID: 27335668 PMCID: PMC4890855 DOI: 10.5402/2012/708203] [Citation(s) in RCA: 15] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 10/02/2012] [Accepted: 10/22/2012] [Indexed: 01/12/2023]
Abstract
In the last decade, there has been an explosion of publications on the assembly of β-barrel outer membrane proteins (OMPs), which carry out diverse cellular functions, including solute transport, protein secretion, and assembly of protein and lipid components of the outer membrane. Of the three outer membrane model systems—Gram-negative bacteria, mitochondria and chloroplasts—research on bacterial and mitochondrial systems has so far led the way in dissecting the β-barrel OMP assembly pathways. Many exciting discoveries have been made, including the identification of β-barrel OMP assembly machineries in bacteria and mitochondria, and potentially the core assembly component in chloroplasts. The atomic structures of all five components of the bacterial β-barrel assembly machinery (BAM) complex, except the β-barrel domain of the core BamA protein, have been solved. Structures reveal that these proteins contain domains/motifs known to facilitate protein-protein interactions, which are at the heart of the assembly pathways. While structural information has been valuable, most of our current understanding of the β-barrel OMP assembly pathways has come from genetic, molecular biology, and biochemical analyses. This paper provides a comparative account of the β-barrel OMP assembly pathways in Gram-negative bacteria, mitochondria, and chloroplasts.
Collapse
Affiliation(s)
- Rajeev Misra
- School of Life Sciences, Arizona State University, Tempe, AZ 85287, USA
| |
Collapse
|
48
|
Werneburg M, Zerbe K, Juhas M, Bigler L, Stalder U, Kaech A, Ziegler U, Obrecht D, Eberl L, Robinson JA. Inhibition of lipopolysaccharide transport to the outer membrane in Pseudomonas aeruginosa by peptidomimetic antibiotics. Chembiochem 2012; 13:1767-75. [PMID: 22807320 DOI: 10.1002/cbic.201200276] [Citation(s) in RCA: 76] [Impact Index Per Article: 6.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/24/2012] [Indexed: 11/08/2022]
Abstract
The asymmetric outer membrane (OM) of Gram-negative bacteria contains lipopolysaccharide (LPS) in the outer leaflet and phospholipid in the inner leaflet. During OM biogenesis, LPS is transported from the periplasm into the outer leaflet by a complex comprising the OM proteins LptD and LptE. Recently, a new family of macrocyclic peptidomimetic antibiotics that interact with LptD of the opportunistic human pathogen Pseudomonas aeruginosa was discovered. Here we provide evidence that the peptidomimetics inhibit the LPS transport function of LptD. One approach to monitor LPS transport involved studies of lipid A modifications. Some modifications occur only in the inner membrane while others occur only in the OM, and thus provide markers for LPS transport within the bacterial envelope. We prepared a conditional lptD mutant of P. aeruginosa PAO1 that allowed control of lptD expression from the rhamnose promoter. With this mutant, the effects caused by the antibiotic on the wild-type strain were compared with those caused by depleting LptD in the mutant strain. When LptD was depleted in the mutant, electron microscopy revealed accumulation of membrane-like material within cells and OM blebbing; this mirrored similar effects in the wild-type strain caused by the antibiotic. Moreover, the bacterium responded to the antibiotic, and to depletion of LptD, by introducing the same lipid A modifications, consistent with inhibition by the antibiotic of LptD-mediated LPS transport. This conclusion was further supported by monitoring the radiolabelling of LPS from [¹⁴C]acetate, and by fractionation of IM and OM components. Overall, the results provide support for a mechanism of action for the peptidomimetic antibiotics that involves inhibition of LPS transport to the cell surface.
Collapse
Affiliation(s)
- Martina Werneburg
- Chemistry Department, University of Zürich, Winterthurerstrasse 190, 8057 Zürich, Switzerland
| | | | | | | | | | | | | | | | | | | |
Collapse
|
49
|
PpiA, a surface PPIase of the cyclophilin family in Lactococcus lactis. PLoS One 2012; 7:e33516. [PMID: 22442694 PMCID: PMC3307742 DOI: 10.1371/journal.pone.0033516] [Citation(s) in RCA: 15] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/07/2011] [Accepted: 02/10/2012] [Indexed: 12/05/2022] Open
Abstract
Background Protein folding in the envelope is a crucial limiting step of protein export and secretion. In order to better understand this process in Lactococcus lactis, a lactic acid bacterium, genes encoding putative exported folding factors like Peptidyl Prolyl Isomerases (PPIases) were searched for in lactococcal genomes. Results In L. lactis, a new putative membrane PPIase of the cyclophilin subfamily, PpiA, was identified and characterized. ppiA gene was found to be constitutively expressed under normal and stress (heat shock, H2O2) conditions. Under normal conditions, PpiA protein was synthesized and released from intact cells by an exogenously added protease, showing that it was exposed at the cell surface. No obvious phenotype could be associated to a ppiA mutant strain under several laboratory conditions including stress conditions, except a very low sensitivity to H2O2. Induction of a ppiA copy provided in trans had no effect i) on the thermosensitivity of an mutant strain deficient for the lactococcal surface protease HtrA and ii) on the secretion and stability on four exported proteins (a highly degraded hybrid protein and three heterologous secreted proteins) in an otherwise wild-type strain background. However, a recombinant soluble form of PpiA that had been produced and secreted in L. lactis and purified from a culture supernatant displayed both PPIase and chaperone activities. Conclusions Although L. lactis PpiA, a protein produced and exposed at the cell surface under normal conditions, displayed a very moderate role in vivo, it was found, as a recombinant soluble form, to be endowed with folding activities in vitro.
Collapse
|
50
|
Naveed H, Jimenez-Morales D, Tian J, Pasupuleti V, Kenney LJ, Liang J. Engineered oligomerization state of OmpF protein through computational design decouples oligomer dissociation from unfolding. J Mol Biol 2012; 419:89-101. [PMID: 22391420 DOI: 10.1016/j.jmb.2012.02.043] [Citation(s) in RCA: 24] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/17/2012] [Revised: 02/24/2012] [Accepted: 02/25/2012] [Indexed: 12/14/2022]
Abstract
Biogenesis of β-barrel membrane proteins is a complex, multistep, and as yet incompletely characterized process. The bacterial porin family is perhaps the best-studied protein family among β-barrel membrane proteins that allows diffusion of small solutes across the bacterial outer membrane. In this study, we have identified residues that contribute significantly to the protein-protein interaction (PPI) interface between the chains of outer membrane protein F (OmpF), a trimeric porin, using an empirical energy function in conjunction with an evolutionary analysis. By replacing these residues through site-directed mutagenesis either with energetically favorable residues or substitutions that do not occur in natural bacterial outer membrane proteins, we succeeded in engineering OmpF mutants with dimeric and monomeric oligomerization states instead of a trimeric oligomerization state. Moreover, our results suggest that the oligomerization of OmpF proceeds through a series of interactions involving two distinct regions of the extensive PPI interface: two monomers interact to form a dimer through the PPI interface near G19. This dimer then interacts with another monomer through the PPI interface near G135 to form a trimer. We have found that perturbing the PPI interface near G19 results in the formation of the monomeric OmpF only. Thermal denaturation of the designed dimeric OmpF mutant suggests that oligomer dissociation can be separated from the process of protein unfolding. Furthermore, the conserved site near G57 and G59 is important for the PPI interface and might provide the essential scaffold for PPIs.
Collapse
Affiliation(s)
- Hammad Naveed
- Department of Bioengineering, University of Illinois at Chicago, Chicago, IL 60607, USA
| | | | | | | | | | | |
Collapse
|