1
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Guo J, Qiu X, Xie YG, Hua ZS, Wang Y. Regulation of intracellular process by two-component systems: Exploring the mechanism of plasmid-mediated conjugative transfer. WATER RESEARCH 2024; 259:121855. [PMID: 38838482 DOI: 10.1016/j.watres.2024.121855] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 03/20/2024] [Revised: 05/26/2024] [Accepted: 05/29/2024] [Indexed: 06/07/2024]
Abstract
Plasmid-mediated conjugative transfer facilitates the dissemination of antibiotic resistance, yet the comprehensive regulatory mechanisms governing this process remain elusive. Herein, we established pure bacteria and activated sludge conjugation system to investigate the regulatory mechanisms of conjugative transfer, leveraging metformin as an exogenous agent. Transcriptomic analysis unveiled that substantial upregulation of genes associated with the two-component system (e.g., AcrB/AcrA, EnvZ/Omp, and CpxA/CpxR) upon exposure to metformin. Furthermore, downstream regulators of the two-component system, including reactive oxygen species (ROS), cytoplasmic membrane permeability, and adenosine triphosphate (ATP) production, were enhanced by 1.7, 1.4 and 1.1 times, respectively, compared to the control group under 0.1 mg/L metformin exposure. Moreover, flow sorting and high-throughput sequencing revealed increased microbial community diversity among transconjugants in activated sludge systems. Notably, the antibacterial potential of human pathogenic bacteria (e.g., Bacteroides, Escherichia-Shigella, and Lactobacillus) was augmented, posing a potential threat to human health. Our findings shed light on the spread of antibiotic resistance bacteria and assess the ecological risks associated with plasmid-mediated conjugative transfer in wastewater treatment systems.
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Affiliation(s)
- Jingjing Guo
- CAS Key Laboratory of Urban Pollutant Conversion, Department of Environmental Science and Engineering, University of Science and Technology of China, Hefei 230026, China
| | - Xiao Qiu
- CAS Key Laboratory of Urban Pollutant Conversion, Department of Environmental Science and Engineering, University of Science and Technology of China, Hefei 230026, China
| | - Yuan-Guo Xie
- CAS Key Laboratory of Urban Pollutant Conversion, Department of Environmental Science and Engineering, University of Science and Technology of China, Hefei 230026, China
| | - Zheng-Shuang Hua
- CAS Key Laboratory of Urban Pollutant Conversion, Department of Environmental Science and Engineering, University of Science and Technology of China, Hefei 230026, China
| | - Yunkun Wang
- CAS Key Laboratory of Urban Pollutant Conversion, Department of Environmental Science and Engineering, University of Science and Technology of China, Hefei 230026, China.
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2
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Nair AM, Jiang T, Mu B, Zhao R. Plastid Molecular Chaperone HSP90C Interacts with the SecA1 Subunit of Sec Translocase for Thylakoid Protein Transport. PLANTS (BASEL, SWITZERLAND) 2024; 13:1265. [PMID: 38732479 PMCID: PMC11085213 DOI: 10.3390/plants13091265] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 03/21/2024] [Revised: 04/24/2024] [Accepted: 04/29/2024] [Indexed: 05/13/2024]
Abstract
The plastid stroma-localized chaperone HSP90C plays a crucial role in maintaining optimal proteostasis within chloroplasts and participates in protein translocation processes. While existing studies have revealed HSP90C's direct interaction with the Sec translocase-dependent client pre-protein PsbO1 and the SecY1 subunit of the thylakoid membrane-bound Sec1 translocase channel system, its direct involvement with the extrinsic homodimeric Sec translocase subunit, SecA1, remains elusive. Employing bimolecular fluorescence complementation (BiFC) assay and other in vitro analyses, we unraveled potential interactions between HSP90C and SecA1. Our investigation revealed dynamic interactions between HSP90C and SecA1 at the thylakoid membrane and stroma. The thylakoid membrane localization of this interaction was contingent upon active HSP90C ATPase activity, whereas their stromal interaction was associated with active SecA1 ATPase activity. Furthermore, we observed a direct interaction between these two proteins by analyzing their ATP hydrolysis activities, and their interaction likely impacts their respective functional cycles. Additionally, using PsbO1, a model Sec translocase client pre-protein, we studied the intricacies of HSP90C's possible involvement in pre-protein translocation via the Sec1 system in chloroplasts. The results suggest a complex nature of the HSP90C-SecA1 interaction, possibly mediated by the Sec client protein. Our studies shed light on the nuanced aspects of HSP90C's engagement in orchestrating pre-protein translocation, and we propose a potential collaborative role of HSP90C with SecA1 in actively facilitating pre-protein transport across the thylakoid membrane.
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Affiliation(s)
| | | | | | - Rongmin Zhao
- Department of Biological Sciences, University of Toronto Scarborough, Toronto, ON M1C 1A4, Canada; Department of Cell & Systems Biology, University of Toronto, Toronto, ON M5S 3B2, Canada; (A.M.N.); (T.J.); (B.M.)
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3
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Shang W, Lichtenberg E, Mlesnita AM, Wilde A, Koch HG. The contribution of mRNA targeting to spatial protein localization in bacteria. FEBS J 2024. [PMID: 38226707 DOI: 10.1111/febs.17054] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/16/2023] [Revised: 11/27/2023] [Accepted: 01/08/2024] [Indexed: 01/17/2024]
Abstract
About 30% of all bacterial proteins execute their function outside of the cytosol and must be inserted into or translocated across the cytoplasmic membrane. This requires efficient targeting systems that recognize N-terminal signal sequences in client proteins and deliver them to protein transport complexes in the membrane. While the importance of these protein transport machineries for the spatial organization of the bacterial cell is well documented in multiple studies, the contribution of mRNA targeting and localized translation to protein transport is only beginning to emerge. mRNAs can exhibit diverse subcellular localizations in the bacterial cell and can accumulate at sites where new protein is required. This is frequently observed for mRNAs encoding membrane proteins, but the physiological importance of membrane enrichment of mRNAs and the consequences it has for the insertion of the encoded protein have not been explored in detail. Here, we briefly highlight some basic concepts of signal sequence-based protein targeting and describe in more detail strategies that enable the monitoring of mRNA localization in bacterial cells and potential mechanisms that route mRNAs to particular positions within the cell. Finally, we summarize some recent developments that demonstrate that mRNA targeting and localized translation can sustain membrane protein insertion under stress conditions when the protein-targeting machinery is compromised. Thus, mRNA targeting likely acts as a back-up strategy and complements the canonical signal sequence-based protein targeting.
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Affiliation(s)
- Wenkang Shang
- Institute of Biochemistry and Molecular Biology, ZBMZ, Faculty of Medicine, Albert-Ludwigs University Freiburg, Germany
- Faculty of Biology, Albert-Ludwigs University Freiburg, Germany
| | | | - Andreea Mihaela Mlesnita
- Institute of Biochemistry and Molecular Biology, ZBMZ, Faculty of Medicine, Albert-Ludwigs University Freiburg, Germany
| | - Annegret Wilde
- Faculty of Biology, Albert-Ludwigs University Freiburg, Germany
| | - Hans-Georg Koch
- Institute of Biochemistry and Molecular Biology, ZBMZ, Faculty of Medicine, Albert-Ludwigs University Freiburg, Germany
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4
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Jian T, Su Q, Liu Y, Seoh HK, Houghton JE, Tai PC, Huang X. Structure-Based Virtual Screening of Helicobacter pylori SecA Inhibitors. IEEE Trans Nanobioscience 2023; 22:933-942. [PMID: 37030876 DOI: 10.1109/tnb.2023.3259946] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 04/10/2023]
Abstract
The human bacterial pathogen Helicobacter pylori causes a range of gastric diseases. The killing rate of Helicobacter pylori is declining year by year because of high antibiotics resistance. It is urgent to develop new target and novel anti- Helicobacter pylori drugs. As an "energy pump" for bacterial cells, SecA is essential for bacterial growth and drives bacterial protein transmembrane transport, moreover SecA is absent in mammals, all of which nominate SecA as an attractive antimicrobial target. Here, we provided a structure-based virtual screening method to screen the 3D-diversity natural-product-like screening library against SecA for novel anti- Helicobacter pylori inhibitors with novel scaffolds. In this study, homology modeling was used to construct the three-dimensional structure of Helicobacter pylori SecA. Two rounds of molecular docking were then used to find new small-molecule inhibitors of SecA, identifying six lead candidates that maintained key interactions with the binding pocket. After that, molecular dynamics simulations were used to explore more accurate ligand-receptor binding modes in states close to natural conditions. Encouragingly, all six compounds were relatively stable during the simulation. Apart from that the binding free energy calculation based on MM/PBSA demonstrated favorable results of < -13.642 kcal/mol. Finally, ADME-T analysis indicated that these compounds were also sufficiently druggable. All six compounds can be well combined with the crystal structure, which further facilitate the development of SecA inhibitors and lead compounds against Helicobacter pylori.
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5
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Barik K, Arya PK, Singh AK, Kumar A. Potential therapeutic targets for combating Mycoplasma genitalium. 3 Biotech 2023; 13:9. [PMID: 36532859 PMCID: PMC9755450 DOI: 10.1007/s13205-022-03423-9] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/22/2022] [Accepted: 12/05/2022] [Indexed: 12/23/2022] Open
Abstract
Mycoplasma genitalium (M. genitalium) has emerged as a sexually transmitted infection (STI) all over the world in the last three decades. It has been identified as a cause of male urethritis, and there is now evidence that it also causes cervicitis and pelvic inflammatory disease in women. However, the precise role of M. genitalium in diseases such as pelvic inflammatory disease, and infertility is unknown, and more research is required. It is a slow-growing organism, and with the advent of the nucleic acid amplification test (NAAT), more studies are being conducted and knowledge about the pathogenicity of this organism is being elucidated. The accumulation of data has improved our understanding of the pathogen and its role in disease transmission. Despite the widespread use of single-dose azithromycin in the sexual health field, M. genitalium is known to rapidly develop antibiotic resistance. As a result, the media frequently refer to this pathogen as the "new STI superbug." Despite their rarity, antibiotics available today have serious side effects. As the cure rates for first-line antimicrobials have decreased, it is now a challenge to determine the effective antimicrobial therapy. In this review, we summarise recent M. genitalium research and investigate potential therapeutic targets for combating this pathogen.
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Affiliation(s)
- Krishnendu Barik
- Department of Bioinformatics, Central University of South Bihar, Gaya, 824236 India
| | - Praffulla Kumar Arya
- Department of Bioinformatics, Central University of South Bihar, Gaya, 824236 India
| | - Ajay Kumar Singh
- Department of Bioinformatics, Central University of South Bihar, Gaya, 824236 India
| | - Anil Kumar
- Department of Bioinformatics, Central University of South Bihar, Gaya, 824236 India
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6
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Agrawal A, Bandi CK, Burgin T, Woo Y, Mayes HB, Chundawat SPS. Click-Chemistry-Based Free Azide versus Azido Sugar Detection Enables Rapid In Vivo Screening of Glycosynthase Activity. ACS Chem Biol 2021; 16:2490-2501. [PMID: 34499469 DOI: 10.1021/acschembio.1c00585] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
Abstract
Engineering of carbohydrate-active enzymes such as glycosynthases to enable chemoenzymatic synthesis of bespoke oligosaccharides has been limited by the lack of suitable ultrahigh-throughput screening methods capable of robustly detecting either starting substrates or end-products of the glycosidic bond formation reaction. Currently, there are limited screening methods available for rapid and highly sensitive single-cell-based screening of glycosynthase enzymes employing azido sugars as activated donor glycosyl substrates. Here, we report a fluorescence-based approach employing click-chemistry for the selective detection of glycosyl azides as substrates versus free inorganic azides as reaction products that facilitated an ultrahigh-throughput in vivo single-cell-based assay of glycosynthase activity. This assay was developed based on the distinct differences observed in relative fluorescence intensity of the triazole-containing fluorophore product formed during the click-chemistry reaction of organic glycosyl azides versus inorganic azides. This discovery formed the basis for proof of concept validation of a directed evolution methodology for screening and sorting glycosynthase mutants capable of synthesis of targeted fucosylated oligosaccharides. Our screening approach facilitated fluorescence-activated cell sorting of an error-prone polymerase chain reaction-based mutant library of fucosynthases expressed in Escherichia coli to identify several novel mutants that showed increased activity for β-fucosyl azide-activated donor sugars toward desired acceptor sugars (e.g., pNP-xylose and lactose). Finally, we discuss avenues for improving this proof of concept in vivo assay method to identify better glycosynthase mutants and further demonstrate the broader applicability of this screening methodology for synthesis of bespoke glycans.
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Affiliation(s)
- Ayushi Agrawal
- Department of Chemical & Biochemical Engineering, Rutgers The State University of New Jersey, 98 Brett Road, Piscataway, New Jersey 08854, United States
| | - Chandra Kanth Bandi
- Department of Chemical & Biochemical Engineering, Rutgers The State University of New Jersey, 98 Brett Road, Piscataway, New Jersey 08854, United States
| | - Tucker Burgin
- Department of Chemical Engineering, University of Michigan Ann Arbor, 2800 Plymouth Avenue, Ann Arbor, Michigan 48105, United States
| | - Youngwoo Woo
- Department of Chemical Engineering, University of Michigan Ann Arbor, 2800 Plymouth Avenue, Ann Arbor, Michigan 48105, United States
| | - Heather B. Mayes
- Department of Chemical Engineering, University of Michigan Ann Arbor, 2800 Plymouth Avenue, Ann Arbor, Michigan 48105, United States
- National Bioenergy Center, National Renewable Energy Laboratory, 15013 Denver West Parkway, Golden, Colorado 80401, United States
| | - Shishir P. S. Chundawat
- Department of Chemical & Biochemical Engineering, Rutgers The State University of New Jersey, 98 Brett Road, Piscataway, New Jersey 08854, United States
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7
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Endo Y, Shimizu Y, Nishikawa H, Sawasato K, Nishiyama KI. Interplay between MPIase, YidC, and PMF during Sec-independent insertion of membrane proteins. Life Sci Alliance 2021; 5:5/1/e202101162. [PMID: 34642230 PMCID: PMC8548208 DOI: 10.26508/lsa.202101162] [Citation(s) in RCA: 7] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/18/2021] [Revised: 09/30/2021] [Accepted: 10/01/2021] [Indexed: 11/24/2022] Open
Abstract
Charges in the N-terminal region and the synthesis level of membrane proteins with N-out topology determine YidC and PMF dependencies with the interplay between glycolipid MPIase, YidC, and PMF. Integral membrane proteins with the N-out topology are inserted into membranes usually in YidC- and PMF-dependent manners. The molecular basis of the various dependencies on insertion factors is not fully understood. A model protein, Pf3-Lep, is inserted independently of both YidC and PMF, whereas the V15D mutant requires both YidC and PMF in vivo. We analyzed the mechanisms that determine the insertion factor dependency in vitro. Glycolipid MPIase was required for insertion of both proteins because MPIase depletion caused a significant defect in insertion. On the other hand, YidC depletion and PMF dissipation had no effects on Pf3-Lep insertion, whereas V15D insertion was reduced. We reconstituted (proteo)liposomes containing MPIase, YidC, and/or F0F1-ATPase. MPIase was essential for insertion of both proteins. YidC and PMF stimulated Pf3-Lep insertion as the synthesis level increased. V15D insertion was stimulated by both YidC and PMF irrespective of the synthesis level. These results indicate that charges in the N-terminal region and the synthesis level are the determinants of YidC and PMF dependencies with the interplay between MPIase, YidC, and PMF.
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Affiliation(s)
- Yuta Endo
- The United Graduate School of Agricultural Sciences, Iwate University, Morioka, Japan
| | - Yuko Shimizu
- Department of Biological Chemistry and Food Science, Faculty of Agriculture, Iwate University, Morioka, Japan
| | - Hanako Nishikawa
- Department of Biological Chemistry and Food Science, Faculty of Agriculture, Iwate University, Morioka, Japan
| | - Katsuhiro Sawasato
- Department of Biological Chemistry and Food Science, Faculty of Agriculture, Iwate University, Morioka, Japan
| | - Ken-Ichi Nishiyama
- The United Graduate School of Agricultural Sciences, Iwate University, Morioka, Japan .,Department of Biological Chemistry and Food Science, Faculty of Agriculture, Iwate University, Morioka, Japan
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8
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Potteth US, Upadhyay T, Saini S, Saraogi I. Novel Antibacterial Targets in Protein Biogenesis Pathways. Chembiochem 2021; 23:e202100459. [PMID: 34643994 DOI: 10.1002/cbic.202100459] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/30/2021] [Revised: 10/12/2021] [Indexed: 11/11/2022]
Abstract
Antibiotic resistance has emerged as a global threat due to the ability of bacteria to quickly evolve in response to the selection pressure induced by anti-infective drugs. Thus, there is an urgent need to develop new antibiotics against resistant bacteria. In this review, we discuss pathways involving bacterial protein biogenesis as attractive antibacterial targets since many of them are essential for bacterial survival and virulence. We discuss the structural understanding of various components associated with bacterial protein biogenesis, which in turn can be utilized for rational antibiotic design. We highlight efforts made towards developing inhibitors of these pathways with insights into future possibilities and challenges. We also briefly discuss other potential targets related to protein biogenesis.
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Affiliation(s)
- Upasana S Potteth
- Department of Biological Sciences, Indian Institute of Science Education and Research Bhopal, Bhauri, Bhopal Bypass Road, Bhopal, 462066, Madhya Pradesh, India
| | - Tulsi Upadhyay
- Department of Biological Sciences, Indian Institute of Science Education and Research Bhopal, Bhauri, Bhopal Bypass Road, Bhopal, 462066, Madhya Pradesh, India
| | - Snehlata Saini
- Department of Biological Sciences, Indian Institute of Science Education and Research Bhopal, Bhauri, Bhopal Bypass Road, Bhopal, 462066, Madhya Pradesh, India
| | - Ishu Saraogi
- Department of Biological Sciences, Indian Institute of Science Education and Research Bhopal, Bhauri, Bhopal Bypass Road, Bhopal, 462066, Madhya Pradesh, India.,Department of Chemistry, Indian Institute of Science Education and Research Bhopal, Bhauri, Bhopal Bypass Road, Bhopal - 462066, Madhya Pradesh, India
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9
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Ali S, Alam M, Hasan GM, Hassan MI. Potential therapeutic targets of Klebsiella pneumoniae: a multi-omics review perspective. Brief Funct Genomics 2021; 21:63-77. [PMID: 34448478 DOI: 10.1093/bfgp/elab038] [Citation(s) in RCA: 28] [Impact Index Per Article: 9.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/02/2021] [Revised: 08/03/2021] [Accepted: 08/04/2021] [Indexed: 11/15/2022] Open
Abstract
The multidrug resistance developed in many organisms due to the prolonged use of antibiotics has been an increasing global health crisis. Klebsiella pneumoniae is a causal organism for various infections, including respiratory, urinary tract and biliary diseases. Initially, immunocompromised individuals are primarily affected by K. pneumoniae. Due to the emergence of hypervirulent strains recently, both healthy and immunocompetent individuals are equally susceptible to K. pneumoniae infections. The infections caused by multidrug-resistant and hypervirulent K. pneumoniae strains are complicated to treat, illustrating an urgent need to develop novel and more practical approaches to combat the pathogen. We focused on the previously performed high-throughput analyses by other groups to discover several novel enzymes that may be considered attractive drug targets of K. pneumoniae. These targets qualify most of the selection criteria for drug targeting, including an absence of its homolog's gene in the host. The capsule, lipopolysaccharide, fimbriae, siderophores and essential virulence factors facilitate the pathogen entry, infection and survival inside the host. This review discusses K. pneumoniae pathophysiology, including its virulence determinants and further the potential drug targets that might facilitate the discovery of novel drugs and effective treatment regimens shortly.
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Affiliation(s)
- Sabeeha Ali
- Centre for Interdisciplinary Research in Basic Sciences, Jamia Millia Islamia, Jamia Nagar New Delhi 110025, India
| | - Manzar Alam
- Centre for Interdisciplinary Research in Basic Sciences, Jamia Millia Islamia, Jamia Nagar New Delhi 110025, India
| | - Gulam Mustafa Hasan
- Department of Biochemistry, College of Medicine, Prince Sattam Bin Abdulaziz University, Al-Kharj, Saudi Arabia
| | - Md Imtaiyaz Hassan
- Centre for Interdisciplinary Research in Basic Sciences, Jamia Millia Islamia, Jamia Nagar New Delhi 110025, India
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10
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Membrane Insertion of the M13 Minor Coat Protein G3p Is Dependent on YidC and the SecAYEG Translocase. Viruses 2021; 13:v13071414. [PMID: 34372619 PMCID: PMC8310372 DOI: 10.3390/v13071414] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/21/2021] [Revised: 07/14/2021] [Accepted: 07/14/2021] [Indexed: 01/01/2023] Open
Abstract
The minor coat protein G3p of bacteriophage M13 is the key component for the host interaction of this virus and binds to Escherichia coli at the tip of the F pili. As we show here, during the biosynthesis of G3p as a preprotein, the signal sequence interacts primarily with SecY, whereas the hydrophobic anchor sequence at the C-terminus interacts with YidC. Using arrested nascent chains and thiol crosslinking, we show here that the ribosome-exposed signal sequence is first contacted by SecY but not by YidC, suggesting that only SecYEG is involved at this early stage. The protein has a large periplasmic domain, a hydrophobic anchor sequence of 21 residues and a short C-terminal tail that remains in the cytoplasm. During the later synthesis of the entire G3p, the residues 387, 389 and 392 in anchor domain contact YidC in its hydrophobic slide to hold translocation of the C-terminal tail. Finally, the protein is processed by leader peptidase and assembled into new progeny phage particles that are extruded out of the cell.
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11
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Oswald J, Njenga R, Natriashvili A, Sarmah P, Koch HG. The Dynamic SecYEG Translocon. Front Mol Biosci 2021; 8:664241. [PMID: 33937339 PMCID: PMC8082313 DOI: 10.3389/fmolb.2021.664241] [Citation(s) in RCA: 28] [Impact Index Per Article: 9.3] [Reference Citation Analysis] [Abstract] [Key Words] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/04/2021] [Accepted: 03/24/2021] [Indexed: 12/13/2022] Open
Abstract
The spatial and temporal coordination of protein transport is an essential cornerstone of the bacterial adaptation to different environmental conditions. By adjusting the protein composition of extra-cytosolic compartments, like the inner and outer membranes or the periplasmic space, protein transport mechanisms help shaping protein homeostasis in response to various metabolic cues. The universally conserved SecYEG translocon acts at the center of bacterial protein transport and mediates the translocation of newly synthesized proteins into and across the cytoplasmic membrane. The ability of the SecYEG translocon to transport an enormous variety of different substrates is in part determined by its ability to interact with multiple targeting factors, chaperones and accessory proteins. These interactions are crucial for the assisted passage of newly synthesized proteins from the cytosol into the different bacterial compartments. In this review, we summarize the current knowledge about SecYEG-mediated protein transport, primarily in the model organism Escherichia coli, and describe the dynamic interaction of the SecYEG translocon with its multiple partner proteins. We furthermore highlight how protein transport is regulated and explore recent developments in using the SecYEG translocon as an antimicrobial target.
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Affiliation(s)
- Julia Oswald
- Institute for Biochemistry and Molecular Biology, Zentrum für Biochemie und Molekulare Medizin (ZMBZ), Faculty of Medicine, Albert Ludwigs Universität Freiburg, Freiburg, Germany
| | - Robert Njenga
- Institute for Biochemistry and Molecular Biology, Zentrum für Biochemie und Molekulare Medizin (ZMBZ), Faculty of Medicine, Albert Ludwigs Universität Freiburg, Freiburg, Germany.,Faculty of Biology, Albert Ludwigs Universität Freiburg, Freiburg, Germany
| | - Ana Natriashvili
- Institute for Biochemistry and Molecular Biology, Zentrum für Biochemie und Molekulare Medizin (ZMBZ), Faculty of Medicine, Albert Ludwigs Universität Freiburg, Freiburg, Germany.,Faculty of Biology, Albert Ludwigs Universität Freiburg, Freiburg, Germany
| | - Pinku Sarmah
- Institute for Biochemistry and Molecular Biology, Zentrum für Biochemie und Molekulare Medizin (ZMBZ), Faculty of Medicine, Albert Ludwigs Universität Freiburg, Freiburg, Germany.,Faculty of Biology, Albert Ludwigs Universität Freiburg, Freiburg, Germany
| | - Hans-Georg Koch
- Institute for Biochemistry and Molecular Biology, Zentrum für Biochemie und Molekulare Medizin (ZMBZ), Faculty of Medicine, Albert Ludwigs Universität Freiburg, Freiburg, Germany
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12
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Jiang C, Wynne M, Huber D. How Quality Control Systems AID Sec-Dependent Protein Translocation. Front Mol Biosci 2021; 8:669376. [PMID: 33928127 PMCID: PMC8076867 DOI: 10.3389/fmolb.2021.669376] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/18/2021] [Accepted: 03/17/2021] [Indexed: 02/01/2023] Open
Abstract
The evolutionarily conserved Sec machinery is responsible for transporting proteins across the cytoplasmic membrane. Protein substrates of the Sec machinery must be in an unfolded conformation in order to be translocated across (or inserted into) the cytoplasmic membrane. In bacteria, the requirement for unfolded proteins is strict: substrate proteins that fold (or misfold) prematurely in the cytoplasm prior to translocation become irreversibly trapped in the cytoplasm. Partially folded Sec substrate proteins and stalled ribosomes containing nascent Sec substrates can also inhibit translocation by blocking (i.e., “jamming”) the membrane-embedded Sec machinery. To avoid these issues, bacteria have evolved a complex network of quality control systems to ensure that Sec substrate proteins do not fold in the cytoplasm. This quality control network can be broken into three branches, for which we have defined the acronym “AID”: (i) avoidance of cytoplasmic intermediates through cotranslationally channeling newly synthesized Sec substrates to the Sec machinery; (ii) inhibition of folding Sec substrate proteins that transiently reside in the cytoplasm by molecular chaperones and the requirement for posttranslational modifications; (iii) destruction of products that could potentially inhibit translocation. In addition, several stress response pathways help to restore protein-folding homeostasis when environmental conditions that inhibit translocation overcome the AID quality control systems.
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Affiliation(s)
- Chen Jiang
- School of Biosciences and the Institute for Microbiology and Infection, University of Birmingham, Birmingham, United Kingdom
| | - Max Wynne
- School of Biosciences and the Institute for Microbiology and Infection, University of Birmingham, Birmingham, United Kingdom
| | - Damon Huber
- School of Biosciences and the Institute for Microbiology and Infection, University of Birmingham, Birmingham, United Kingdom
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13
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Šebela M, Raus M, Ondřej V, Hašler P. The Influence of Metabolic Inhibitors, Antibiotics, and Microgravity on Intact Cell MALDI-TOF Mass Spectra of the Cyanobacterium Synechococcus Sp. UPOC S4. Molecules 2021; 26:molecules26061683. [PMID: 33802864 PMCID: PMC8002600 DOI: 10.3390/molecules26061683] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/15/2021] [Revised: 03/02/2021] [Accepted: 03/11/2021] [Indexed: 11/28/2022] Open
Abstract
The aim and novelty of this paper are found in assessing the influence of inhibitors and antibiotics on intact cell MALDI-TOF mass spectra of the cyanobacterium Synechococcus sp. UPOC S4 and to check the impact on reliability of identification. Defining the limits of this method is important for its use in biology and applied science. The compounds included inhibitors of respiration, glycolysis, citrate cycle, and proteosynthesis. They were used at 1–10 μM concentrations and different periods of up to 3 weeks. Cells were also grown without inhibitors in a microgravity because of expected strong effects. Mass spectra were evaluated using controls and interpreted in terms of differential peaks and their assignment to protein sequences by mass. Antibiotics, azide, and bromopyruvate had the greatest impact. The spectral patterns were markedly altered after a prolonged incubation at higher concentrations, which precluded identification in the database of reference spectra. The incubation in microgravity showed a similar effect. These differences were evident in dendrograms constructed from the spectral data. Enzyme inhibitors affected the spectra to a smaller extent. This study shows that only a long-term presence of antibiotics and strong metabolic inhibitors in the medium at 10−5 M concentrations hinders the correct identification of cyanobacteria by matrix-assisted laser desorption/ionization time-of-flight mass spectrometry (MALDI-TOF).
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Affiliation(s)
- Marek Šebela
- Department of Biochemistry and Centre of the Region Haná for Biotechnological and Agricultural Research, Faculty of Science, Palacký University, Šlechtitelů 27, CZ-783 71 Olomouc, Czech Republic;
- Correspondence: (M.Š.); (P.H.)
| | - Martin Raus
- Department of Biochemistry and Centre of the Region Haná for Biotechnological and Agricultural Research, Faculty of Science, Palacký University, Šlechtitelů 27, CZ-783 71 Olomouc, Czech Republic;
| | - Vladan Ondřej
- Department of Botany, Faculty of Science, Palacký University, Šlechtitelů 27, CZ-783 71 Olomouc, Czech Republic;
| | - Petr Hašler
- Department of Botany, Faculty of Science, Palacký University, Šlechtitelů 27, CZ-783 71 Olomouc, Czech Republic;
- Correspondence: (M.Š.); (P.H.)
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14
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Effective Small Molecule Antibacterials from a Novel Anti-Protein Secretion Screen. Microorganisms 2021; 9:microorganisms9030592. [PMID: 33805695 PMCID: PMC8000395 DOI: 10.3390/microorganisms9030592] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/18/2021] [Revised: 03/09/2021] [Accepted: 03/10/2021] [Indexed: 12/03/2022] Open
Abstract
The increasing problem of bacterial resistance to antibiotics underscores the urgent need for new antibacterials. Protein export pathways are attractive potential targets. The Sec pathway is essential for bacterial viability and includes components that are absent from eukaryotes. Here, we used a new high-throughput in vivo screen based on the secretion and activity of alkaline phosphatase (PhoA), a Sec-dependent secreted enzyme that becomes active in the periplasm. The assay was optimized for a luminescence-based substrate and was used to screen a ~240K small molecule compound library. After hit confirmation and analoging, 14 HTS secretion inhibitors (HSI), belonging to eight structural classes, were identified with IC50 < 60 µM. The inhibitors were evaluated as antibacterials against 19 Gram-negative and Gram-positive bacterial species (including those from the WHO’s top pathogens list). Seven of them—HSI#6, 9; HSI#1, 5, 10; and HSI#12, 14—representing three structural families, were bacteriocidal. HSI#6 was the most potent hit against 13 species of both Gram-negative and Gram-positive bacteria with IC50 of 0.4 to 8.7 μM. HSI#1, 5, 9 and 10 inhibited the viability of Gram-positive bacteria with IC50 ~6.9–77.8 μM. HSI#9, 12, and 14 inhibited the viability of E. coli strains with IC50 < 65 μM. Moreover, HSI#1, 5 and 10 inhibited the viability of an E. coli strain missing TolC to improve permeability with IC50 4 to 14 μM, indicating their inability to penetrate the outer membrane. The antimicrobial activity was not related to the inhibition of the SecA component of the translocase in vitro, and hence, HSI molecules may target new unknown components that directly or indirectly affect protein secretion. The results provided proof of the principle that the new broad HTS approach can yield attractive nanomolar inhibitors that have potential as new starting compounds for optimization to derive potential antibiotics.
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15
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Icke C, Hodges FJ, Pullela K, McKeand SA, Bryant JA, Cunningham AF, Cole JA, Henderson IR. Glycine acylation and trafficking of a new class of bacterial lipoprotein by a composite secretion system. eLife 2021; 10:63762. [PMID: 33625358 PMCID: PMC7943197 DOI: 10.7554/elife.63762] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/06/2020] [Accepted: 02/23/2021] [Indexed: 01/21/2023] Open
Abstract
Protein acylation is critical for many cellular functions across all domains of life. In bacteria, lipoproteins have important roles in virulence and are targets for the development of antimicrobials and vaccines. Bacterial lipoproteins are secreted from the cytosol via the Sec pathway and acylated on an N-terminal cysteine residue through the action of three enzymes. In Gram-negative bacteria, the Lol pathway transports lipoproteins to the outer membrane. Here, we demonstrate that the Aat secretion system is a composite system sharing similarity with elements of a type I secretion systems and the Lol pathway. During secretion, the AatD subunit acylates the substrate CexE on a highly conserved N-terminal glycine residue. Mutations disrupting glycine acylation interfere with membrane incorporation and trafficking. Our data reveal CexE as the first member of a new class of glycine-acylated lipoprotein, while Aat represents a new secretion system that displays the substrate lipoprotein on the cell surface.
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Affiliation(s)
- Christopher Icke
- Institute for Molecular Bioscience, University of Queensland, Brisbane, Australia
| | - Freya J Hodges
- Institute for Molecular Bioscience, University of Queensland, Brisbane, Australia
| | - Karthik Pullela
- Institute for Molecular Bioscience, University of Queensland, Brisbane, Australia
| | | | | | - Adam F Cunningham
- Institute of Microbiology and Infection, Birmingham, United Kingdom.,Institute of Immunology and Immunotherapy, University of Birmingham, Birmingham, United Kingdom
| | - Jeff A Cole
- Institute of Microbiology and Infection, Birmingham, United Kingdom
| | - Ian R Henderson
- Institute for Molecular Bioscience, University of Queensland, Brisbane, Australia
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16
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Seinen AB, Spakman D, van Oijen AM, Driessen AJM. Cellular dynamics of the SecA ATPase at the single molecule level. Sci Rep 2021; 11:1433. [PMID: 33446830 PMCID: PMC7809386 DOI: 10.1038/s41598-021-81081-2] [Citation(s) in RCA: 9] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/03/2020] [Accepted: 01/04/2021] [Indexed: 12/04/2022] Open
Abstract
In bacteria, the SecA ATPase provides the driving force for protein secretion via the SecYEG translocon. While the dynamic interplay between SecA and SecYEG in translocation is widely appreciated, it is not clear how SecA associates with the translocon in the crowded cellular environment. We use super-resolution microscopy to directly visualize the dynamics of SecA in Escherichia coli at the single-molecule level. We find that SecA is predominantly associated with and evenly distributed along the cytoplasmic membrane as a homodimer, with only a minor cytosolic fraction. SecA moves along the cell membrane as three distinct but interconvertible diffusional populations: (1) A state loosely associated with the membrane, (2) an integral membrane form, and (3) a temporarily immobile form. Disruption of the proton-motive-force, which is essential for protein secretion, re-localizes a significant portion of SecA to the cytoplasm and results in the transient location of SecA at specific locations at the membrane. The data support a model in which SecA diffuses along the membrane surface to gain access to the SecYEG translocon.
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Affiliation(s)
- Anne-Bart Seinen
- Department of Molecular Microbiology, Groningen Biomolecular Sciences and Biotechnology Institute, and the Zernike Institute for Advanced Materials, University of Groningen, Groningen, The Netherlands.,AMOLF, Science Park 104, 1098 XG, Amsterdam, The Netherlands
| | - Dian Spakman
- Department of Molecular Microbiology, Groningen Biomolecular Sciences and Biotechnology Institute, and the Zernike Institute for Advanced Materials, University of Groningen, Groningen, The Netherlands
| | | | - Arnold J M Driessen
- Department of Molecular Microbiology, Groningen Biomolecular Sciences and Biotechnology Institute, and the Zernike Institute for Advanced Materials, University of Groningen, Groningen, The Netherlands.
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17
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Multiple ways to kill bacteria via inhibiting novel cell wall or membrane targets. Future Med Chem 2020; 12:1253-1279. [PMID: 32538147 DOI: 10.4155/fmc-2020-0046] [Citation(s) in RCA: 23] [Impact Index Per Article: 5.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/20/2022] Open
Abstract
The rise of antibiotic-resistant infections has been well documented and the need for novel antibiotics cannot be overemphasized. US FDA approved antibiotics target only a small fraction of bacterial cell wall or membrane components, well-validated antimicrobial targets. In this review, we highlight small molecules that inhibit relatively unexplored cell wall and membrane targets. Some of these targets include teichoic acids-related proteins (DltA, LtaS, TarG and TarO), lipid II, Mur family enzymes, components of LPS assembly (MsbA, LptA, LptB and LptD), penicillin-binding protein 2a in methicillin-resistant Staphylococcus aureus, outer membrane protein transport (such as LepB and BamA) and lipoprotein transport components (LspA, LolC, LolD and LolE). Inhibitors of SecA, cell division protein, FtsZ and compounds that kill persister cells via membrane targeting are also covered.
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18
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Cranford-Smith T, Jamshad M, Jeeves M, Chandler RA, Yule J, Robinson A, Alam F, Dunne KA, Aponte Angarita EH, Alanazi M, Carter C, Henderson IR, Lovett JE, Winn P, Knowles T, Huber D. Iron is a ligand of SecA-like metal-binding domains in vivo. J Biol Chem 2020; 295:7516-7528. [PMID: 32241912 PMCID: PMC7247292 DOI: 10.1074/jbc.ra120.012611] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/10/2020] [Revised: 03/26/2020] [Indexed: 12/12/2022] Open
Abstract
The ATPase SecA is an essential component of the bacterial Sec machinery, which transports proteins across the cytoplasmic membrane. Most SecA proteins contain a long C-terminal tail (CTT). In Escherichia coli, the CTT contains a structurally flexible linker domain and a small metal-binding domain (MBD). The MBD coordinates zinc via a conserved cysteine-containing motif and binds to SecB and ribosomes. In this study, we screened a high-density transposon library for mutants that affect the susceptibility of E. coli to sodium azide, which inhibits SecA-mediated translocation. Results from sequencing this library suggested that mutations removing the CTT make E. coli less susceptible to sodium azide at subinhibitory concentrations. Copurification experiments suggested that the MBD binds to iron and that azide disrupts iron binding. Azide also disrupted binding of SecA to membranes. Two other E. coli proteins that contain SecA-like MBDs, YecA and YchJ, also copurified with iron, and NMR spectroscopy experiments indicated that YecA binds iron via its MBD. Competition experiments and equilibrium binding measurements indicated that the SecA MBD binds preferentially to iron and that a conserved serine is required for this specificity. Finally, structural modeling suggested a plausible model for the octahedral coordination of iron. Taken together, our results suggest that SecA-like MBDs likely bind to iron in vivo.
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Affiliation(s)
- Tamar Cranford-Smith
- School of Biosciences, University of Birmingham, Birmingham B15 2TT, United Kingdom
| | - Mohammed Jamshad
- School of Biosciences, University of Birmingham, Birmingham B15 2TT, United Kingdom
| | - Mark Jeeves
- Institute of Cancer and Genomic Sciences, University of Birmingham, Birmingham B15 2TT, United Kingdom
| | - Rachael A Chandler
- School of Biosciences, University of Birmingham, Birmingham B15 2TT, United Kingdom
| | - Jack Yule
- School of Biosciences, University of Birmingham, Birmingham B15 2TT, United Kingdom
| | - Ashley Robinson
- Institute for Microbiology and Infection, University of Birmingham, Birmingham B15 2TT, United Kingdom
| | - Farhana Alam
- School of Biosciences, University of Birmingham, Birmingham B15 2TT, United Kingdom
| | - Karl A Dunne
- Institute for Microbiology and Infection, University of Birmingham, Birmingham B15 2TT, United Kingdom
| | - Edwin H Aponte Angarita
- Centre for Computational Biology, University of Birmingham, Birmingham B15 2TT, United Kingdom
| | - Mashael Alanazi
- School of Biosciences, University of Birmingham, Birmingham B15 2TT, United Kingdom; Department of Biology, College of Science, Jouf University, Saudi Arabia
| | - Cailean Carter
- School of Biosciences, University of Birmingham, Birmingham B15 2TT, United Kingdom
| | - Ian R Henderson
- Institute for Microbiology and Infection, University of Birmingham, Birmingham B15 2TT, United Kingdom
| | - Janet E Lovett
- SUPA, School of Physics and Astronomy and BSRC, University of St. Andrews, St. Andrews KY16 9SS, United Kingdom
| | - Peter Winn
- School of Biosciences, University of Birmingham, Birmingham B15 2TT, United Kingdom; Centre for Computational Biology, University of Birmingham, Birmingham B15 2TT, United Kingdom
| | - Timothy Knowles
- School of Biosciences, University of Birmingham, Birmingham B15 2TT, United Kingdom
| | - Damon Huber
- School of Biosciences, University of Birmingham, Birmingham B15 2TT, United Kingdom.
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19
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De Geyter J, Portaliou AG, Srinivasu B, Krishnamurthy S, Economou A, Karamanou S. Trigger factor is a bona fide secretory pathway chaperone that interacts with SecB and the translocase. EMBO Rep 2020; 21:e49054. [PMID: 32307852 DOI: 10.15252/embr.201949054] [Citation(s) in RCA: 21] [Impact Index Per Article: 5.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/16/2019] [Revised: 03/09/2020] [Accepted: 03/19/2020] [Indexed: 11/09/2022] Open
Abstract
Bacterial secretory preproteins are translocated across the inner membrane post-translationally by the SecYEG-SecA translocase. Mature domain features and signal peptides maintain preproteins in kinetically trapped, largely soluble, folding intermediates. Some aggregation-prone preproteins require chaperones, like trigger factor (TF) and SecB, for solubility and/or targeting. TF antagonizes the contribution of SecB to secretion by an unknown molecular mechanism. We reconstituted this interaction in vitro and studied targeting and secretion of the model preprotein pro-OmpA. TF and SecB display distinct, unsuspected roles in secretion. Tightly associating TF:pro-OmpA targets the translocase at SecA, but TF prevents pro-OmpA secretion. In solution, SecB binds TF:pro-OmpA with high affinity. At the membrane, when bound to the SecA C-tail, SecB increases TF and TF:pro-OmpA affinities for the translocase and allows pro-OmpA to resume translocation. Our data reveal that TF, a main cytoplasmic folding pathway chaperone, is also a bona fide post-translational secretory chaperone that directly interacts with both SecB and the translocase to mediate regulated protein secretion. Thus, TF links the cytoplasmic folding and secretion chaperone networks.
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Affiliation(s)
- Jozefien De Geyter
- Department of Microbiology and Immunology, Rega Institute for Medical Research, Laboratory of Molecular Bacteriology, KU Leuven, Leuven, Belgium
| | - Athina G Portaliou
- Department of Microbiology and Immunology, Rega Institute for Medical Research, Laboratory of Molecular Bacteriology, KU Leuven, Leuven, Belgium
| | - Bindu Srinivasu
- Department of Microbiology and Immunology, Rega Institute for Medical Research, Laboratory of Molecular Bacteriology, KU Leuven, Leuven, Belgium
| | - Srinath Krishnamurthy
- Department of Microbiology and Immunology, Rega Institute for Medical Research, Laboratory of Molecular Bacteriology, KU Leuven, Leuven, Belgium
| | - Anastassios Economou
- Department of Microbiology and Immunology, Rega Institute for Medical Research, Laboratory of Molecular Bacteriology, KU Leuven, Leuven, Belgium
| | - Spyridoula Karamanou
- Department of Microbiology and Immunology, Rega Institute for Medical Research, Laboratory of Molecular Bacteriology, KU Leuven, Leuven, Belgium
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20
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Naha A, Mandal RS, Samanta P, Saha RN, Shaw S, Ghosh A, Chatterjee NS, Dutta P, Okamoto K, Dutta S, Mukhopadhyay AK. Deciphering the possible role of ctxB7 allele on higher production of cholera toxin by Haitian variant Vibrio cholerae O1. PLoS Negl Trop Dis 2020; 14:e0008128. [PMID: 32236098 PMCID: PMC7112172 DOI: 10.1371/journal.pntd.0008128] [Citation(s) in RCA: 13] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/02/2019] [Accepted: 02/10/2020] [Indexed: 12/16/2022] Open
Abstract
Cholera continues to be an important public health concern in developing countries where proper hygiene and sanitation are compromised. This severe diarrheal disease is caused by the Gram-negative pathogen Vibrio cholerae belonging to serogroups O1 and O139. Cholera toxin (CT) is the prime virulence factor and is directly responsible for the disease manifestation. The ctxB gene encodes cholera toxin B subunit (CTB) whereas the A subunit (CTA) is the product of ctxA gene. Enzymatic action of CT depends on binding of B pentamers to the lipid-based receptor ganglioside GM1. In recent years, emergence of V. cholerae Haitian variant strains with ctxB7 allele and their rapid spread throughout the globe has been linked to various cholera outbreaks in Africa and Asia. These strains produce classical type (WT) CTB except for an additional mutation in the signal sequence region where an asparagine (N) residue replaces a histidine (H) at the 20th amino acid position (H20N) of CTB precursor (pre-CTB). Here we report that Haitian variant V. cholerae O1 strains isolated in Kolkata produced higher amount of CT compared to contemporary O1 El Tor variant strains under in vitro virulence inducing conditions. We observed that the ctxB7 allele, itself plays a pivotal role in higher CT production. Based on our in silico analysis, we hypothesized that higher accumulation of toxin subunits from ctxB7 allele might be attributed to the structural alteration at the CTB signal peptide region of pre-H20N CTB. Overall, this study provides plausible explanation regarding the hypertoxigenic phenotype of the Haitian variant strains which have spread globally, possibly through positive selection for increased pathogenic traits.
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Affiliation(s)
- Arindam Naha
- Division of Bacteriology, ICMR-National Institute of Cholera and Enteric Diseases, Kolkata, India
| | - Rahul Shubhra Mandal
- Biomedical Informatics Center, ICMR-National Institute of Cholera and Enteric Diseases, Kolkata, India
| | - Prosenjit Samanta
- Division of Bacteriology, ICMR-National Institute of Cholera and Enteric Diseases, Kolkata, India
| | - Rudra Narayan Saha
- Division of Bacteriology, ICMR-National Institute of Cholera and Enteric Diseases, Kolkata, India
| | - Sreeja Shaw
- Division of Bacteriology, ICMR-National Institute of Cholera and Enteric Diseases, Kolkata, India
| | - Amit Ghosh
- Division of Bacteriology, ICMR-National Institute of Cholera and Enteric Diseases, Kolkata, India
| | | | - Pujarini Dutta
- Division of Clinical Medicine, ICMR-National Institute of Cholera and Enteric Diseases, Kolkata, India
| | - Keinosuke Okamoto
- Collaborative Research Center of Okayama University for Infectious Diseases at NICED, Kolkata, India
| | - Shanta Dutta
- Division of Bacteriology, ICMR-National Institute of Cholera and Enteric Diseases, Kolkata, India
| | - Asish Kumar Mukhopadhyay
- Division of Bacteriology, ICMR-National Institute of Cholera and Enteric Diseases, Kolkata, India
- * E-mail:
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21
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Xin C, Ban X, Gu Z, Li C, Cheng L, Hong Y, Li Z. Non-classical secretion of 1,4-alpha-glucan branching enzymes without signal peptides in Escherichia coli. Int J Biol Macromol 2019; 132:759-765. [DOI: 10.1016/j.ijbiomac.2019.04.002] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/05/2018] [Revised: 04/01/2019] [Accepted: 04/01/2019] [Indexed: 11/16/2022]
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22
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Complete Genome Sequence of Escherichia coli MT102, a Plasmid-Free Recipient Resistant to Rifampin, Azide, and Streptomycin, Used in Conjugation Experiments. Microbiol Resour Announc 2019; 8:8/20/e00383-19. [PMID: 31097507 PMCID: PMC6522792 DOI: 10.1128/mra.00383-19] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/30/2022] Open
Abstract
We present here the complete genome sequence of Escherichia coli MT102, which is resistant to rifampin, azide, and streptomycin and is used as a recipient in plasmid transfer experiments. The sequence will be utilized for chromosomal read removal in plasmid sequence analyses obtained from transconjugants within this strain and in comprehensive genetic studies. We present here the complete genome sequence of Escherichia coli MT102, which is resistant to rifampin, azide, and streptomycin and is used as a recipient in plasmid transfer experiments. The sequence will be utilized for chromosomal read removal in plasmid sequence analyses obtained from transconjugants within this strain and in comprehensive genetic studies.
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23
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Soto-Rodríguez J, Baneyx F. Role of the signal sequence in proteorhodopsin biogenesis in E. coli. Biotechnol Bioeng 2018; 116:912-918. [PMID: 30475397 DOI: 10.1002/bit.26878] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/06/2018] [Revised: 10/16/2018] [Accepted: 11/21/2018] [Indexed: 12/16/2022]
Abstract
Blue-absorbing proteorhodopsin (BPR) from marine bacteria is a retinal-bound, light-activated, outwards proton transporter containing seven α-helical transmembrane segments (TMS). It is synthesized as a precursor species (pre-BPR) with a predicted N-terminal signal sequence that is cleaved to yield the mature protein. While optimizing the production of BPR in Escherichia coli to facilitate the construction of bioprotonic devices, we observed significant pre-BPR accumulation in the inner membrane and explored signal sequence requirements and export pathway. We report here that BPR does not rely on the Sec pathway for inner membrane integration, and that although it greatly enhances yields, its signal sequence is not necessary to obtain a functional product. We further show that an unprocessable version of pre-BPR obtained by mutagenesis of the signal peptidase I site exhibits all functional attributes of the wild-type protein and has the advantage of being produced at higher levels. Our results are consistent with the BPR signal sequence being recognized by the signal recognition particle (SRP; a protein that orchestrates the cotranslational biogenesis of inner membrane proteins) and serving as a beneficial "pro" domain rather than a traditional secretory peptide.
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Affiliation(s)
| | - François Baneyx
- Department of Chemical Engineering, University of Washington, Seattle, Washington
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24
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Jin J, Hsieh YH, Chaudhary AS, Cui J, Houghton JE, Sui SF, Wang B, Tai PC. SecA inhibitors as potential antimicrobial agents: differential actions on SecA-only and SecA-SecYEG protein-conducting channels. FEMS Microbiol Lett 2018; 365:5037921. [PMID: 30007321 PMCID: PMC7190897 DOI: 10.1093/femsle/fny145] [Citation(s) in RCA: 10] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/31/2018] [Accepted: 06/13/2018] [Indexed: 12/13/2022] Open
Abstract
Sec-dependent protein translocation is an essential process in bacteria. SecA is a key component of the translocation machinery and has multiple domains that interact with various ligands. SecA acts as an ATPase motor to drive the precursor protein/peptide through the SecYEG protein translocation channels. As SecA is unique to bacteria and there is no mammalian counterpart, it is an ideal target for the development of new antimicrobials. Several reviews detail the assays for ATPase and protein translocation, as well as the search for SecA inhibitors. Recent studies have shown that, in addition to the SecA-SecYEG translocation channels, there are SecA-only channels in the lipid bilayers, which function independently from the SecYEG machinery. This mini-review focuses on recent advances on the newly developed SecA inhibitors that allow the evaluation of their potential as antimicrobial agents, as well as a fundamental understanding of mechanisms of SecA function(s). These SecA inhibitors abrogate the effects of efflux pumps in both Gram-positive and Gram-negative bacteria. We also discuss recent findings that SecA binds to ribosomes and nascent peptides, which suggest other roles of SecA. A model for the multiple roles of SecA is presented.
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Affiliation(s)
- Jinshan Jin
- Department of Biology, Center for Biotechnology and Drug Design and Georgia State University, Atlanta, GA 30303, USA
| | - Ying-Hsin Hsieh
- Department of Biology, Center for Biotechnology and Drug Design and Georgia State University, Atlanta, GA 30303, USA
| | - Arpana S Chaudhary
- Department of Chemistry, Center for Biotechnology and Drug Design and Georgia State University, P.O. Box 3965, Atlanta, GA 30303, USA
| | - Jianmei Cui
- Department of Chemistry, Center for Biotechnology and Drug Design and Georgia State University, P.O. Box 3965, Atlanta, GA 30303, USA
| | - John E Houghton
- Department of Biology, Center for Biotechnology and Drug Design and Georgia State University, Atlanta, GA 30303, USA
| | - Sen-fang Sui
- State Key Laboratory of Membrane Biology, Center for Structural Biology, School of Life Sciences, Tsinghua University, Beijing 100084, China
| | - Binghe Wang
- Department of Chemistry, Center for Biotechnology and Drug Design and Georgia State University, P.O. Box 3965, Atlanta, GA 30303, USA
| | - Phang C Tai
- Department of Biology, Center for Biotechnology and Drug Design and Georgia State University, Atlanta, GA 30303, USA
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25
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Complete Genome Sequence of Escherichia coli ME8067, an Azide-Resistant Laboratory Strain Used for Conjugation Experiments. GENOME ANNOUNCEMENTS 2018; 6:6/25/e00515-18. [PMID: 29930039 PMCID: PMC6013617 DOI: 10.1128/genomea.00515-18] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Subscribe] [Scholar Register] [Indexed: 11/20/2022]
Abstract
We report here the complete genome sequence of Escherichia coli ME8067, an azide-resistant laboratory strain used for conjugation experiments. The ME8067 genome was closely related to E. coli strain K-12 substrain W3110. This genome sequence will support further genetic analysis of conjugative elements.
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26
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Complete Genome Sequence of Escherichia coli J53, an Azide-Resistant Laboratory Strain Used for Conjugation Experiments. GENOME ANNOUNCEMENTS 2018; 6:6/21/e00433-18. [PMID: 29798920 PMCID: PMC5968721 DOI: 10.1128/genomea.00433-18] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Subscribe] [Scholar Register] [Indexed: 11/20/2022]
Abstract
We report here the complete genome sequence of Escherichia coli J53, which is used as a recipient in conjugation experiments and is a laboratory strain derived from E. coli K-12. This genome sequence will help in the development of a comprehensive genetic analysis of conjugative elements.
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27
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Tsirigotaki A, Chatzi KE, Koukaki M, De Geyter J, Portaliou AG, Orfanoudaki G, Sardis MF, Trelle MB, Jørgensen TJD, Karamanou S, Economou A. Long-Lived Folding Intermediates Predominate the Targeting-Competent Secretome. Structure 2018; 26:695-707.e5. [PMID: 29606594 DOI: 10.1016/j.str.2018.03.006] [Citation(s) in RCA: 26] [Impact Index Per Article: 4.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/06/2017] [Revised: 02/02/2018] [Accepted: 03/08/2018] [Indexed: 10/17/2022]
Abstract
Secretory preproteins carry signal peptides fused amino-terminally to mature domains. They are post-translationally targeted to cross the plasma membrane in non-folded states with the help of translocases, and fold only at their final destinations. The mechanism of this process of postponed folding is unknown, but is generally attributed to signal peptides and chaperones. We herein demonstrate that, during targeting, most mature domains maintain loosely packed folding intermediates. These largely soluble states are signal peptide independent and essential for translocase recognition. These intermediates are promoted by mature domain features: residue composition, elevated disorder, and reduced hydrophobicity. Consequently, a mature domain folds slower than its cytoplasmic structural homolog. Some mature domains could not evolve stable, loose intermediates, and hence depend on signal peptides for slow folding to the detriment of solubility. These unique features of secretory proteins impact our understanding of protein trafficking, folding, and aggregation, and thus place them in a distinct class.
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Affiliation(s)
- Alexandra Tsirigotaki
- KU Leuven, Department of Microbiology and Immunology, Rega Institute for Medical Research, Laboratory of Molecular Bacteriology, 3000 Leuven, Belgium
| | - Katerina E Chatzi
- KU Leuven, Department of Microbiology and Immunology, Rega Institute for Medical Research, Laboratory of Molecular Bacteriology, 3000 Leuven, Belgium
| | - Marina Koukaki
- Institute of Molecular Biology and Biotechnology, FoRTH, University of Crete, 70013 Heraklion, Crete, Greece
| | - Jozefien De Geyter
- KU Leuven, Department of Microbiology and Immunology, Rega Institute for Medical Research, Laboratory of Molecular Bacteriology, 3000 Leuven, Belgium
| | - Athina G Portaliou
- KU Leuven, Department of Microbiology and Immunology, Rega Institute for Medical Research, Laboratory of Molecular Bacteriology, 3000 Leuven, Belgium
| | - Georgia Orfanoudaki
- Institute of Molecular Biology and Biotechnology, FoRTH, University of Crete, 70013 Heraklion, Crete, Greece
| | - Marios Frantzeskos Sardis
- KU Leuven, Department of Microbiology and Immunology, Rega Institute for Medical Research, Laboratory of Molecular Bacteriology, 3000 Leuven, Belgium
| | - Morten Beck Trelle
- Department of Biochemistry and Molecular Biology, University of Southern Denmark, 5230 Odense M, Denmark
| | - Thomas J D Jørgensen
- Department of Biochemistry and Molecular Biology, University of Southern Denmark, 5230 Odense M, Denmark
| | - Spyridoula Karamanou
- KU Leuven, Department of Microbiology and Immunology, Rega Institute for Medical Research, Laboratory of Molecular Bacteriology, 3000 Leuven, Belgium
| | - Anastassios Economou
- KU Leuven, Department of Microbiology and Immunology, Rega Institute for Medical Research, Laboratory of Molecular Bacteriology, 3000 Leuven, Belgium.
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Hsieh YH, Zhang H, Jin J, Dai C, Jiang C, Wang B, Tai PC. Biphasic actions of SecA inhibitors on Prl/Sec suppressors: Possible physiological roles of SecA-only channels. Biochem Biophys Res Commun 2017; 482:296-300. [PMID: 27856243 DOI: 10.1016/j.bbrc.2016.11.057] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/07/2016] [Accepted: 11/11/2016] [Indexed: 11/30/2022]
Abstract
SecA is an essential component in the bacterial Sec-dependent protein translocation process. We previously showed that in addition to the ubiquitous, high-affinity SecYEG-SecDF·YajC protein translocation channel, there is a low-affinity SecA-only channel that elicits ion channel activity and promotes protein translocation. The SecA-only channels are less efficient, and like Prl suppressors, lack signal peptide specificity; they function in the absence of signal peptides. The presence of SecYEG-SecDF·YajC alters the sensitivity of ATPase inhibitor Rose Bengal. In this study, we found that the suppressor membranes are much more resistant to inhibition by Rose Bengal. Similar results have been found for a SecA-specific inhibitor. Moreover, biphasic responses of inhibition of ion current and protein translocation activities were observed for many PrlA/SecY and PrlG/SecE suppressor membranes, with a low IC50 value similar to that of the SecA-only channels and a very high IC50. However, the suppressor strains are as sensitive to the inhibitor as the parental strain, suggesting that SecA-only channels have some essential physiological function(s) in the cells that are inhibited by the specific SecA inhibitor.
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Affiliation(s)
- Ying-Hsin Hsieh
- Department of Biology, Georgia State University, Atlanta, GA 30303, USA
| | - Hao Zhang
- Department of Biology, Georgia State University, Atlanta, GA 30303, USA
| | - Jinshan Jin
- Department of Biology, Georgia State University, Atlanta, GA 30303, USA
| | - Chaofeng Dai
- Department of Chemistry, Georgia State University, Atlanta, GA 30303, USA
| | - Chun Jiang
- Department of Biology, Georgia State University, Atlanta, GA 30303, USA
| | - Binghe Wang
- Department of Chemistry, Georgia State University, Atlanta, GA 30303, USA
| | - Phang C Tai
- Department of Biology, Georgia State University, Atlanta, GA 30303, USA; Center for Biotechnology and Drug Design, Georgia State University, Atlanta, GA 30303, USA.
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Jin J, Hsieh YH, Cui J, Damera K, Dai C, Chaudhary AS, Zhang H, Yang H, Cao N, Jiang C, Vaara M, Wang B, Tai PC. Using Chemical Probes to Assess the Feasibility of Targeting SecA for Developing Antimicrobial Agents against Gram-Negative Bacteria. ChemMedChem 2016; 11:2511-2521. [PMID: 27753464 PMCID: PMC5189635 DOI: 10.1002/cmdc.201600421] [Citation(s) in RCA: 10] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/19/2016] [Revised: 09/25/2016] [Indexed: 11/07/2022]
Abstract
With the widespread emergence of drug resistance, there is an urgent need to search for new antimicrobials, especially those against Gram-negative bacteria. Along this line, the identification of viable targets is a critical first step. The protein translocase SecA is commonly believed to be an excellent target for the development of broad-spectrum antimicrobials. In recent years, we developed three structural classes of SecA inhibitors that have proven to be very effective against Gram-positive bacteria. However, we have not achieved the same level of success against Gram-negative bacteria, despite the potent inhibition of SecA in enzyme assays by the same inhibitors. In this study, we use representative inhibitors as chemical probes to gain an understanding as to why these inhibitors were not effective against Gram-negative bacteria. The results validate our initial postulation that the major difference in effectiveness against Gram-positive and Gram-negative bacteria is in the additional permeability barrier posed by the outer membrane of Gram-negative bacteria. We also found that the expression of efflux pumps, which are responsible for multidrug resistance (MDR), have no effect on the effectiveness of these SecA inhibitors. Identification of an inhibitor-resistant mutant and complementation tests of the plasmids containing secA in a secAts mutant showed that a single secA-azi-9 mutation increased the resistance, providing genetic evidence that SecA is indeed the target of these inhibitors in bacteria. Such results strongly suggest SecA as an excellent target for developing effective antimicrobials against Gram-negative bacteria with the intrinsic ability to overcome MDR. A key future research direction should be the optimization of membrane permeability.
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Affiliation(s)
- Jinshan Jin
- Department of Biology, Center for Biotechnology and Drug Design, and Center for Diagnostics and Therapeutics, Georgia State University, Atlanta, GA 30303
| | - Ying-Hsin Hsieh
- Department of Biology, Center for Biotechnology and Drug Design, and Center for Diagnostics and Therapeutics, Georgia State University, Atlanta, GA 30303
| | - Jianmei Cui
- Department of Chemistry, Center for Biotechnology and Drug Design, and Center for Diagnostics and Therapeutics, Georgia State University, Atlanta, GA 30303
| | - Krishna Damera
- Department of Chemistry, Center for Biotechnology and Drug Design, and Center for Diagnostics and Therapeutics, Georgia State University, Atlanta, GA 30303
| | - Chaofeng Dai
- Department of Chemistry, Center for Biotechnology and Drug Design, and Center for Diagnostics and Therapeutics, Georgia State University, Atlanta, GA 30303
| | - Arpana S. Chaudhary
- Department of Chemistry, Center for Biotechnology and Drug Design, and Center for Diagnostics and Therapeutics, Georgia State University, Atlanta, GA 30303
| | - Hao Zhang
- Department of Biology, Center for Biotechnology and Drug Design, and Center for Diagnostics and Therapeutics, Georgia State University, Atlanta, GA 30303
| | - Hsiuchin Yang
- Department of Biology, Center for Biotechnology and Drug Design, and Center for Diagnostics and Therapeutics, Georgia State University, Atlanta, GA 30303
| | - Nannan Cao
- Department of Biology, Center for Biotechnology and Drug Design, and Center for Diagnostics and Therapeutics, Georgia State University, Atlanta, GA 30303
| | - Chun Jiang
- Department of Biology, Center for Biotechnology and Drug Design, and Center for Diagnostics and Therapeutics, Georgia State University, Atlanta, GA 30303
| | - Martti Vaara
- Division of Clinical Microbiology, Helsinki University Hospital, FI-00029 HUSLAB, Helsinki, Finland, and Northern Antibiotics Ltd, FI-00720, Helsinki, Finland
| | - Binghe Wang
- Department of Chemistry, Center for Biotechnology and Drug Design, and Center for Diagnostics and Therapeutics, Georgia State University, Atlanta, GA 30303
| | - Phang C. Tai
- Department of Biology, Center for Biotechnology and Drug Design, and Center for Diagnostics and Therapeutics, Georgia State University, Atlanta, GA 30303
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Vladoiu MC, Labrie M, Létourneau M, Egesborg P, Gagné D, Billard É, Grosset AA, Doucet N, Chatenet D, St-Pierre Y. Design of a peptidic inhibitor that targets the dimer interface of a prototypic galectin. Oncotarget 2016; 6:40970-80. [PMID: 26543238 PMCID: PMC4747383 DOI: 10.18632/oncotarget.5403] [Citation(s) in RCA: 17] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/13/2015] [Accepted: 08/20/2015] [Indexed: 12/30/2022] Open
Abstract
Galectins are small soluble lectins that bind β-galactosides via their carbohydrate recognition domain (CRD). Their ability to dimerize is critical for the crosslinking of glycoprotein receptors and subsequent cellular signaling. This is particularly important in their immunomodulatory role via the induction of T-cell apoptosis. Because galectins play a central role in many pathologies, including cancer, they represent valuable therapeutic targets. At present, most inhibitors have been directed towards the CRD, a challenging task in terms of specificity given the high structural homology of the CRD among galectins. Such inhibitors are not effective at targeting CRD-independent functions of galectins. Here, we report a new class of galectin inhibitors that specifically binds human galectin-7 (hGal-7), disrupts the formation of homodimers, and inhibits the pro-apoptotic activity of hGal-7 on Jurkat T cells. In addition to representing a new means to achieve specificity when targeting galectins, such inhibitors provide a promising alternative to more conventional galectin inhibitors that target the CRD with soluble glycans or other small molecular weight allosteric inhibitors.
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Affiliation(s)
| | - Marilyne Labrie
- INRS-Institut Armand-Frappier, Université du Québec, Laval, Québec, H7V 1B7 Canada
| | - Myriam Létourneau
- INRS-Institut Armand-Frappier, Université du Québec, Laval, Québec, H7V 1B7 Canada
| | - Philippe Egesborg
- INRS-Institut Armand-Frappier, Université du Québec, Laval, Québec, H7V 1B7 Canada
| | - Donald Gagné
- INRS-Institut Armand-Frappier, Université du Québec, Laval, Québec, H7V 1B7 Canada
| | - Étienne Billard
- INRS-Institut Armand-Frappier, Université du Québec, Laval, Québec, H7V 1B7 Canada
| | - Andrée-Anne Grosset
- INRS-Institut Armand-Frappier, Université du Québec, Laval, Québec, H7V 1B7 Canada
| | - Nicolas Doucet
- INRS-Institut Armand-Frappier, Université du Québec, Laval, Québec, H7V 1B7 Canada
| | - David Chatenet
- INRS-Institut Armand-Frappier, Université du Québec, Laval, Québec, H7V 1B7 Canada
| | - Yves St-Pierre
- INRS-Institut Armand-Frappier, Université du Québec, Laval, Québec, H7V 1B7 Canada
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Dajkovic A, Hinde E, MacKichan C, Carballido-Lopez R. Dynamic Organization of SecA and SecY Secretion Complexes in the B. subtilis Membrane. PLoS One 2016; 11:e0157899. [PMID: 27336478 PMCID: PMC4918944 DOI: 10.1371/journal.pone.0157899] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/18/2016] [Accepted: 06/07/2016] [Indexed: 12/21/2022] Open
Abstract
In prokaryotes, about one third of cellular proteins are translocated across the plasma membrane or inserted into it by concerted action of the cytoplasmic ATPase SecA and the universally conserved SecYEG heterotrimeric polypeptide-translocating pore. Secretion complexes have been reported to localize in specific subcellular sites in Bacillus subtilis. In this work, we used a combination of total internal reflection microscopy, scanning fluorescence correlation spectroscopy, and pair correlation function to study the localization and dynamics of SecA and SecY in growing Bacillus subtilis cells. Both SecA and SecY localized in transient and dynamic foci in the cytoplasmic membrane, which displayed no higher-level organization in helices. Foci of SecA and SecY were in constant flux with freely diffusing SecA and SecY molecules. Scanning FCS confirmed the existence of populations of cellular SecA and SecY molecules with a wide range of diffusion coefficients. Diffusion of SecY as an uncomplexed molecular species was short-lived and only local while SecY complexed with its protein partners traversed distances of over half a micrometer in the cell.
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Affiliation(s)
- Alex Dajkovic
- Micalis Institute, INRA, AgroParisTech, Université Paris-Saclay, 78350 Jouy-en-Josas, France
- * E-mail:
| | - Elizabeth Hinde
- School of Medical Sciences, University of New South Wales, Sydney, Australia 2052
| | - Calum MacKichan
- Micalis Institute, INRA, AgroParisTech, Université Paris-Saclay, 78350 Jouy-en-Josas, France
| | - Rut Carballido-Lopez
- Micalis Institute, INRA, AgroParisTech, Université Paris-Saclay, 78350 Jouy-en-Josas, France
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Gao D, Luan Y, Liang Q, Qi Q. Exploring the N-terminal role of a heterologous protein in secreting out ofEscherichia coli. Biotechnol Bioeng 2016; 113:2561-2567. [DOI: 10.1002/bit.26028] [Citation(s) in RCA: 12] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/19/2016] [Revised: 05/25/2016] [Accepted: 06/02/2016] [Indexed: 11/09/2022]
Affiliation(s)
- Dongfang Gao
- State Key Laboratory of Microbial Technology; Shandong University; Jinan 250100 People's Republic of China
| | - Yaqi Luan
- State Key Laboratory of Microbial Technology; Shandong University; Jinan 250100 People's Republic of China
| | - Quanfeng Liang
- State Key Laboratory of Microbial Technology; Shandong University; Jinan 250100 People's Republic of China
| | - Qingsheng Qi
- State Key Laboratory of Microbial Technology; Shandong University; Jinan 250100 People's Republic of China
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Abstract
There is a consensus in the medical profession of the pressing need for novel antimicrobial agents due to issues related to drug resistance. In practice, solutions to this problem to a large degree lie with the identification of new and vital targets in bacteria and subsequently designing their inhibitors. We consider SecA a very promising antimicrobial target. In this review, we compile and analyze information available on SecA to show that inhibition of SecA has a multitude of consequences. Furthermore, we discuss issues critical to the design and evaluation of SecA inhibitors.
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Okuda M, Ohta K, Tominaga K. Vibrational dynamics of azide-derivatized amino acids studied by nonlinear infrared spectroscopy. J Chem Phys 2015; 142:212418. [DOI: 10.1063/1.4917032] [Citation(s) in RCA: 13] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/23/2023] Open
Affiliation(s)
- Masaki Okuda
- Graduate School of Science, Kobe University, Rokkodai-cho 1-1, Nada. Kobe 657-8501, Japan
| | - Kaoru Ohta
- Moleuclar Photoscience Research Center, Kobe University, Rokkodai-cho 1-1, Nada. Kobe 657-8501, Japan
| | - Keisuke Tominaga
- Graduate School of Science, Kobe University, Rokkodai-cho 1-1, Nada. Kobe 657-8501, Japan
- Moleuclar Photoscience Research Center, Kobe University, Rokkodai-cho 1-1, Nada. Kobe 657-8501, Japan
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Rawat S, Zhu L, Lindner E, Dalbey RE, White SH. SecA drives transmembrane insertion of RodZ, an unusual single-span membrane protein. J Mol Biol 2015; 427:1023-37. [PMID: 24846669 PMCID: PMC4233018 DOI: 10.1016/j.jmb.2014.05.005] [Citation(s) in RCA: 20] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/24/2014] [Revised: 04/16/2014] [Accepted: 05/07/2014] [Indexed: 10/25/2022]
Abstract
The transmembrane (TM) helices of most type II single-span membrane proteins (S-SMPs) of Escherichia coli occur near the N-terminus, where the cell's targeting mechanisms can readily identify it as it emerges from the ribosome. However, the TM helices of a few S-SMPs, such as RodZ, occur a hundred or more residues downstream from the N-terminus, which raises fundamental questions about targeting and assembly. Because of RodZ's novelty and potential usefulness for understanding TM helix insertion in vivo, we examined its membrane targeting and assembly. We used RodZ constructs containing immunotags before the TM domain to assess membrane insertion using proteinase K digestion. We confirmed the N(in)-C(out) (type II) topology of RodZ and established the absence of a targeting signal other than the TM domain. RodZ was not inserted into the membrane under SecA depletion conditions or in the presence of sodium azide, which is known to inhibit SecA. Insertion failed when the TM proton gradient was abolished with Carbonyl cyanide m-chlorophenyl hydrazone. Insertion also failed when RodZ was expressed in SecE-depleted E. coli, indicating that the SecYEG translocon is required for RodZ assembly. Protease accessibility assays of RodZ in other E. coli depletion strains revealed that insertion is independent of SecB, YidC, and SecD/F. Insertion was found to be only weakly dependent on the signal recognition particle pathway: insertion was weakly dependent on the Ffh but independent of FtsY. We conclude that membrane insertion of RodZ requires only the SecYEG translocon, the SecA ATPase motor, and the TM proton motive force.
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Affiliation(s)
- Swati Rawat
- Department of Physiology and Biophysics and the Center for Biomembrane Systems, University of California at Irvine, Irvine, CA 92697-4560, USA
| | - Lu Zhu
- Department of Chemistry and Biochemistry, The Ohio State University, Columbus, OH 43210, USA
| | - Eric Lindner
- Department of Physiology and Biophysics and the Center for Biomembrane Systems, University of California at Irvine, Irvine, CA 92697-4560, USA
| | - Ross E Dalbey
- Department of Chemistry and Biochemistry, The Ohio State University, Columbus, OH 43210, USA
| | - Stephen H White
- Department of Physiology and Biophysics and the Center for Biomembrane Systems, University of California at Irvine, Irvine, CA 92697-4560, USA.
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Hsieh YH, Huang YJ, Jin JS, Yu L, Yang H, Jiang C, Wang B, Tai PC. Mechanisms of Rose Bengal inhibition on SecA ATPase and ion channel activities. Biochem Biophys Res Commun 2014; 454:308-12. [PMID: 25450394 DOI: 10.1016/j.bbrc.2014.10.070] [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] [Received: 10/06/2014] [Accepted: 10/14/2014] [Indexed: 10/24/2022]
Abstract
SecA is an essential protein possessing ATPase activity in bacterial protein translocation for which Rose Bengal (RB) is the first reported sub-micromolar inhibitor in ATPase activity and protein translocation. Here, we examined the mechanisms of inhibition on various forms of SecA ATPase by conventional enzymatic assays, and by monitoring the SecA-dependent channel activity in the semi-physiological system in cells. We build on the previous observation that SecA with liposomes form active protein-conducting channels in the oocytes. Such ion channel activity is enhanced by purified Escherichia coli SecYEG-SecDF·YajC liposome complexes. Inhibition by RB could be monitored, providing correlation of in vitro activity and intact cell functionality. In this work, we found the intrinsic SecA ATPase is inhibited by RB competitively at low ATP concentration, and non-competitively at high ATP concentrations while the translocation ATPase with precursors and SecYEG is inhibited non-competitively by RB. The Inhibition by RB on SecA channel activity in the oocytes with exogenous ATP-Mg(2+), mimicking translocation ATPase activity, is also non-competitive. The non-competitive inhibition on channel activity has also been observed with SecA from other bacteria which otherwise would be difficult to examine without the cognate precursors and membranes.
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Affiliation(s)
- Ying-Hsin Hsieh
- Department of Biology, Center of Biotechnology and Drug Design, Georgia State University, Atlanta, GA 30303, United States
| | - Ying-Ju Huang
- Department of Biology, Center of Biotechnology and Drug Design, Georgia State University, Atlanta, GA 30303, United States
| | - Jin-Shan Jin
- Department of Biology, Center of Biotechnology and Drug Design, Georgia State University, Atlanta, GA 30303, United States
| | - Liyan Yu
- Department of Biology, Center of Biotechnology and Drug Design, Georgia State University, Atlanta, GA 30303, United States
| | - Hsiuchin Yang
- Department of Biology, Center of Biotechnology and Drug Design, Georgia State University, Atlanta, GA 30303, United States
| | - Chun Jiang
- Department of Biology, Center of Biotechnology and Drug Design, Georgia State University, Atlanta, GA 30303, United States
| | - Binghe Wang
- Department of Chemistry, Center of Biotechnology and Drug Design, Georgia State University, Atlanta, GA 30303, United States
| | - Phang C Tai
- Department of Biology, Center of Biotechnology and Drug Design, Georgia State University, Atlanta, GA 30303, United States.
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Halbedel S, Reiss S, Hahn B, Albrecht D, Mannala GK, Chakraborty T, Hain T, Engelmann S, Flieger A. A systematic proteomic analysis of Listeria monocytogenes house-keeping protein secretion systems. Mol Cell Proteomics 2014; 13:3063-81. [PMID: 25056936 DOI: 10.1074/mcp.m114.041327] [Citation(s) in RCA: 21] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/06/2022] Open
Abstract
Listeria monocytogenes is a firmicute bacterium causing serious infections in humans upon consumption of contaminated food. Most of its virulence factors are secretory proteins either released to the medium or attached to the bacterial surface. L. monocytogenes encodes at least six different protein secretion pathways. Although great efforts have been made in the past to predict secretory proteins and their secretion routes using bioinformatics, experimental evidence is lacking for most secretion systems. Therefore, we constructed mutants in the main housekeeping protein secretion systems, which are the Sec-dependent transport, the YidC membrane insertases SpoIIIJ and YqjG, as well as the twin-arginine pathway, and analyzed their secretion and virulence defects. Our results demonstrate that Sec-dependent secretion and membrane insertion of proteins via YidC proteins are essential for viability of L. monocytogenes. Depletion of SecA or YidC activity severely affected protein secretion, whereas loss of the Tat-pathway was without any effect on secretion, viability, and virulence. Two-dimensional gel electrophoresis combined with protein identification by mass spectrometry revealed that secretion of many virulence factors and of enzymes synthesizing and degrading the cell wall depends on the SecA route. This finding was confirmed by SecA inhibition experiments using sodium azide. Analysis of secretion of substrates typically dependent on the accessory SecA2 ATPase in wild type and azide resistant mutants of L. monocytogenes revealed for the first time that SecA2-dependent protein secretion also requires the ATPase activity of the house-keeping SecA protein.
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Affiliation(s)
- Sven Halbedel
- From the ‡Robert Koch Institute, FG11 - Division of Enteropathogenic Bacteria and Legionella, Burgstrasse 37, 38855 Wernigerode, Germany;
| | - Swantje Reiss
- §Institute of Microbiology, University of Greifswald, F.-L.-Jahn-Strasse 15, 17487 Greifswald, Germany
| | - Birgit Hahn
- From the ‡Robert Koch Institute, FG11 - Division of Enteropathogenic Bacteria and Legionella, Burgstrasse 37, 38855 Wernigerode, Germany
| | - Dirk Albrecht
- §Institute of Microbiology, University of Greifswald, F.-L.-Jahn-Strasse 15, 17487 Greifswald, Germany
| | - Gopala Krishna Mannala
- ¶Institute of Medical Microbiology, University of Gießen, Schubertstrasse 81, 35392 Gießen, Germany
| | - Trinad Chakraborty
- ¶Institute of Medical Microbiology, University of Gießen, Schubertstrasse 81, 35392 Gießen, Germany
| | - Torsten Hain
- ¶Institute of Medical Microbiology, University of Gießen, Schubertstrasse 81, 35392 Gießen, Germany
| | - Susanne Engelmann
- §Institute of Microbiology, University of Greifswald, F.-L.-Jahn-Strasse 15, 17487 Greifswald, Germany; ‖Institute of Microbiology, Technical University of Braunschweig, Spielmannstrasse 7, 38106 Braunschweig, Germany; **Helmholtz Centre for Infection Research, Microbial Proteomics, Inhoffenstrasse 7, 38124 Braunschweig, Germany
| | - Antje Flieger
- From the ‡Robert Koch Institute, FG11 - Division of Enteropathogenic Bacteria and Legionella, Burgstrasse 37, 38855 Wernigerode, Germany;
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Adachi S, Murakawa Y, Hiraga S. SecA defects are accompanied by dysregulation of MukB, DNA gyrase, chromosome partitioning and DNA superhelicity in Escherichia coli. MICROBIOLOGY-SGM 2014; 160:1648-1658. [PMID: 24858081 DOI: 10.1099/mic.0.077685-0] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/18/2022]
Abstract
Spatial regulation of nucleoids and chromosome-partitioning proteins is important for proper chromosome partitioning in Escherichia coli. However, the underlying molecular mechanisms are unknown. In the present work, we showed that mutation or chemical perturbation of secretory A (SecA), an ATPase component of the membrane protein translocation machinery, SecY, a component of the membrane protein translocation channel and acyl carrier protein P (AcpP), which binds to SecA and MukB, a functional homologue of structural maintenance of chromosomes protein (SMC), resulted in a defect in chromosome partitioning. We further showed that SecA is essential for proper positioning of the oriC DNA region, decatenation and maintenance of superhelicity of DNA. Genetic interaction studies revealed that the topological abnormality observed in the secA mutant was due to combined inhibitory effects of defects in MukB, DNA gyrase and Topo IV, suggesting a role for the membrane protein translocation machinery in chromosome partitioning and/or structural maintenance of chromosomes.
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Affiliation(s)
- Shun Adachi
- Medical Research Project, Institute of Health Biosciences, The University of Tokushima Graduate School, 3-18-15 Kuramoto-cho, Tokushima 770-8503, Japan.,Department of Radiation Genetics, Graduate School of Medicine, Kyoto University, Konoe-cho, Yoshida, Sakyo-ku, Kyoto 606-8501, Japan
| | - Yasuhiro Murakawa
- Max Delbrück Center for Molecular Medicine Berlin-Buch, Robert-Rössle-Str. 10, 13125 Berlin, Germany.,Department of Radiation Genetics, Graduate School of Medicine, Kyoto University, Konoe-cho, Yoshida, Sakyo-ku, Kyoto 606-8501, Japan
| | - Sota Hiraga
- Department of Radiation Genetics, Graduate School of Medicine, Kyoto University, Konoe-cho, Yoshida, Sakyo-ku, Kyoto 606-8501, Japan
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Parsons LM, Cipollo J. Oral ingestion of Microbacterium nematophilum leads to anal-region infection in Caenorhabditis elegans. Microbes Infect 2014; 16:356-61. [DOI: 10.1016/j.micinf.2014.01.002] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/25/2013] [Revised: 12/24/2013] [Accepted: 01/06/2014] [Indexed: 11/30/2022]
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41
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Rao C V S, De Waelheyns E, Economou A, Anné J. Antibiotic targeting of the bacterial secretory pathway. BIOCHIMICA ET BIOPHYSICA ACTA-MOLECULAR CELL RESEARCH 2014; 1843:1762-83. [PMID: 24534745 DOI: 10.1016/j.bbamcr.2014.02.004] [Citation(s) in RCA: 36] [Impact Index Per Article: 3.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 10/31/2013] [Revised: 01/27/2014] [Accepted: 02/06/2014] [Indexed: 02/06/2023]
Abstract
Finding new, effective antibiotics is a challenging research area driven by novel approaches required to tackle unconventional targets. In this review we focus on the bacterial protein secretion pathway as a target for eliminating or disarming pathogens. We discuss the latest developments in targeting the Sec-pathway for novel antibiotics focusing on two key components: SecA, the ATP-driven motor protein responsible for driving preproteins across the cytoplasmic membrane and the Type I signal peptidase that is responsible for the removal of the signal peptide allowing the release of the mature protein from the membrane. We take a bird's-eye view of other potential targets in the Sec-pathway as well as other Sec-dependent or Sec-independent protein secretion pathways as targets for the development of novel antibiotics. This article is part of a Special Issue entitled: Protein trafficking and secretion in bacteria. Guest Editors: Anastassios Economou and Ross Dalbey.
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Affiliation(s)
- Smitha Rao C V
- Laboratory of Molecular Bacteriology, Rega Institute, Department of Microbiology and Immunology, KU Leuven, O&N1, 6th floor, Herestraat 49, P.O. Box 1037, B-3000 Leuven, Belgium.
| | - Evelien De Waelheyns
- Laboratory of Molecular Bacteriology, Rega Institute, Department of Microbiology and Immunology, KU Leuven, O&N1, 6th floor, Herestraat 49, P.O. Box 1037, B-3000 Leuven, Belgium.
| | - Anastassios Economou
- Laboratory of Molecular Bacteriology, Rega Institute, Department of Microbiology and Immunology, KU Leuven, O&N1, 6th floor, Herestraat 49, P.O. Box 1037, B-3000 Leuven, Belgium; Institute of Molecular Biology and Biotechnology, FORTH, University of Crete, P.O. Box 1385, GR-711 10 Iraklio, Crete, Greece; Department of Biology, University of Crete, P.O. Box 1385, GR-71110 Iraklio, Crete, Greece.
| | - Jozef Anné
- Laboratory of Molecular Bacteriology, Rega Institute, Department of Microbiology and Immunology, KU Leuven, O&N1, 6th floor, Herestraat 49, P.O. Box 1037, B-3000 Leuven, Belgium.
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Ishii H, Shirai T, Makino C, Nishikata T. Mitochondrial inhibitor sodium azide inhibits the reorganization of mitochondria-rich cytoplasm and the establishment of the anteroposterior axis in ascidian embryo. Dev Growth Differ 2014; 56:175-88. [DOI: 10.1111/dgd.12117] [Citation(s) in RCA: 18] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/14/2013] [Revised: 12/04/2013] [Accepted: 12/04/2013] [Indexed: 11/30/2022]
Affiliation(s)
- Hirokazu Ishii
- Frontiers of Innovative Research in Science and Technology (FIRST); Konan University; Kobe Hyogo 650-0047 Japan
| | - Takuma Shirai
- Frontiers of Innovative Research in Science and Technology (FIRST); Konan University; Kobe Hyogo 650-0047 Japan
| | - Chisato Makino
- Frontiers of Innovative Research in Science and Technology (FIRST); Konan University; Kobe Hyogo 650-0047 Japan
| | - Takahito Nishikata
- Frontiers of Innovative Research in Science and Technology (FIRST); Konan University; Kobe Hyogo 650-0047 Japan
- Frontier Institute for Biomolecular Engineering Research (FIBER); Konan University; Kobe Hyogo 650-0047 Japan
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43
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Soman R, Yuan J, Kuhn A, Dalbey RE. Polarity and charge of the periplasmic loop determine the YidC and sec translocase requirement for the M13 procoat lep protein. J Biol Chem 2013; 289:1023-32. [PMID: 24275657 DOI: 10.1074/jbc.m113.522250] [Citation(s) in RCA: 15] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/06/2022] Open
Abstract
During membrane biogenesis, the M13 procoat protein is inserted into the lipid bilayer in a strictly YidC-dependent manner with both the hydrophobic signal sequence and the membrane anchor sequence promoting translocation of the periplasmic loop via a hairpin mechanism. Here, we find that the translocase requirements can be altered for PClep in a predictable manner by changing the polarity and charge of the peptide region that is translocated across the membrane. When the polarity of the translocated peptide region is lowered and the charged residues in this region are removed, translocation of this loop region occurs largely by a YidC- and Sec-independent mechanism. When the polarity is increased to that of the wild-type procoat protein, the YidC insertase is essential for translocation. Further increasing the polarity, by adding charged residues, switches the insertion pathway to a YidC/Sec mechanism. Conversely, we find that increasing the hydrophobicity of the transmembrane segments of PClep can decrease the translocase requirement for translocation of the peptide chain. This study provides a framework to understand why the YidC and Sec machineries exist in parallel and demonstrates that the YidC insertase has a limited capacity to translocate a peptide chain on its own.
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Affiliation(s)
- Raunak Soman
- From the Department of Chemistry and Biochemistry, The Ohio State University, Columbus, Ohio 43210 and
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Suppressor analysis reveals a role for SecY in the SecA2-dependent protein export pathway of Mycobacteria. J Bacteriol 2013; 195:4456-65. [PMID: 23913320 DOI: 10.1128/jb.00630-13] [Citation(s) in RCA: 18] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/17/2023] Open
Abstract
All bacteria use the conserved Sec pathway to transport proteins across the cytoplasmic membrane, with the SecA ATPase playing a central role in the process. Mycobacteria are part of a small group of bacteria that have two SecA proteins: the canonical SecA (SecA1) and a second, specialized SecA (SecA2). The SecA2-dependent pathway exports a small subset of proteins and is required for Mycobacterium tuberculosis virulence. The mechanism by which SecA2 drives export of proteins across the cytoplasmic membrane remains poorly understood. Here we performed suppressor analysis on a dominant negative secA2 mutant (secA2 K129R) of the model mycobacterium Mycobacterium smegmatis to better understand the pathway used by SecA2 to export proteins. Two extragenic suppressor mutations were identified as mapping to the promoter region of secY, which encodes the central component of the canonical Sec export channel. These suppressor mutations increased secY expression, and this effect was sufficient to alleviate the secA2 K129R phenotype. We also discovered that the level of SecY protein was greatly diminished in the secA2 K129R mutant, but at least partially restored in the suppressors. Furthermore, the level of SecY in a suppressor strongly correlated with the degree of suppression. Our findings reveal a detrimental effect of SecA2 K129R on SecY, arguing for an integrated system in which SecA2 works with SecY and the canonical Sec translocase to export proteins.
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45
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Cui J, Jin J, Hsieh YH, Yang H, Ke B, Damera K, Tai PC, Wang B. Design, Synthesis and Biological Evaluation of Rose Bengal Analogues as SecA Inhibitors. ChemMedChem 2013; 8:1384-93. [DOI: 10.1002/cmdc.201300216] [Citation(s) in RCA: 26] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/15/2013] [Indexed: 11/06/2022]
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46
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Genome sequence of Escherichia coli J53, a reference strain for genetic studies. J Bacteriol 2012; 194:3742-3. [PMID: 22740669 DOI: 10.1128/jb.00641-12] [Citation(s) in RCA: 38] [Impact Index Per Article: 3.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022] Open
Abstract
Escherichia coli J53 (F(-) met pro Azi(r)) is a derivative of E. coli K-12 which is resistant to sodium azide. This strain has been widely used as a general recipient strain for various conjugation experiments. Here, we report the genome sequence of E. coli J53 (=KACC 16628).
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47
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Chen N, Hong FL, Wang HH, Yuan QH, Ma WY, Gao XN, Shi R, Zhang RJ, Sun CS, Wang SB. Modified recombinant proteins can be exported via the Sec pathway in Escherichia coli. PLoS One 2012; 7:e42519. [PMID: 22912705 PMCID: PMC3418276 DOI: 10.1371/journal.pone.0042519] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/23/2011] [Accepted: 07/10/2012] [Indexed: 01/29/2023] Open
Abstract
The correct folding of a protein is a pre-requirement for its proper posttranslational modification. The Escherichia coli Sec pathway, in which preproteins, in an unfolded, translocation-competent state, are rapidly secreted across the cytoplasmic membrane, is commonly assumed to be unfavorable for their modification in the cytosol. Whether posttranslationally modified recombinant preproteins can be efficiently transported via the Sec pathway, however, remains unclear. ACP and BCCP domain (BCCP87) are carrier proteins that can be converted into active phosphopantetheinylated ACP (holo-ACP) and biotinylated-BCCP (holo-BCCP) by AcpS and BirA, respectively. In the present study, we show that, when ACP or BCCP87 is fused to the C-terminus of secretory protein YebF or MBP, the resulting fusion protein preYebF-ACP, preYebF-BCCP87, preMBP-ACP or preMBP-BCCP87 can be modified and then secreted. Our data demonstrate that posttranslational modification of preYebF-ACP, preYebF-BCCP87 preMBP-ACP and preMBP-BCCP87 can take place in the cytosol prior to translocation, and the Sec machinery accommodates these previously modified fusion proteins. High levels of active holo-ACP and holo-BCCP87 are achieved when AcpS or BirA is co-expressed, especially when sodium azide is used to retard their translocation across the inner membrane. Our results also provide an alternative to achieve a high level of modified recombinant proteins expressed extracellularly.
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Affiliation(s)
- Nan Chen
- College of Life Sciences, South China Agricultural University, Guangzhou, Guangdong, P. R. China
| | - Fu-Lin Hong
- College of Life Sciences, South China Agricultural University, Guangzhou, Guangdong, P. R. China
| | - Hai-Hong Wang
- College of Life Sciences, South China Agricultural University, Guangzhou, Guangdong, P. R. China
| | - Qi-Hang Yuan
- College of Life Sciences, South China Agricultural University, Guangzhou, Guangdong, P. R. China
| | - Wan-Yan Ma
- College of Life Sciences, South China Agricultural University, Guangzhou, Guangdong, P. R. China
| | - Xu-Na Gao
- College of Life Sciences, South China Agricultural University, Guangzhou, Guangdong, P. R. China
| | - Rui Shi
- College of Life Sciences, South China Agricultural University, Guangzhou, Guangdong, P. R. China
| | - Rui-Juan Zhang
- College of Life Sciences, South China Agricultural University, Guangzhou, Guangdong, P. R. China
| | - Chang-Sheng Sun
- College of Life Sciences, South China Agricultural University, Guangzhou, Guangdong, P. R. China
| | - Sheng-Bin Wang
- College of Life Sciences, South China Agricultural University, Guangzhou, Guangdong, P. R. China
- * E-mail:
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48
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Neugebauer SA, Baulig A, Kuhn A, Facey SJ. Membrane Protein Insertion of Variant MscL Proteins Occurs at YidC and SecYEG of Escherichia coli. J Mol Biol 2012; 417:375-86. [DOI: 10.1016/j.jmb.2012.01.046] [Citation(s) in RCA: 18] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/26/2011] [Revised: 12/23/2011] [Accepted: 01/26/2012] [Indexed: 10/14/2022]
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49
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The variable subdomain of Escherichia coli SecA functions to regulate SecA ATPase activity and ADP release. J Bacteriol 2012; 194:2205-13. [PMID: 22389482 DOI: 10.1128/jb.00039-12] [Citation(s) in RCA: 11] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022] Open
Abstract
Bacterial SecA proteins can be categorized by the presence or absence of a variable subdomain (VAR) located within nucleotide-binding domain II of the SecA DEAD motor. Here we show that VAR is dispensable for SecA function, since the VAR deletion mutant secAΔ519-547 displayed a wild-type rate of cellular growth and protein export. Loss or gain of VAR is extremely rare in the history of bacterial evolution, indicating that it appears to contribute to secA function within the relevant species in their natural environments. VAR removal also results in additional secA phenotypes: azide resistance (Azi(r)) and suppression of signal sequence defects (PrlD). The SecAΔ(519-547) protein was found to be modestly hyperactive for SecA ATPase activities and displayed an accelerated rate of ADP release, consistent with the biochemical basis of azide resistance. Based on our findings, we discuss models whereby VAR allosterically regulates SecA DEAD motor function at SecYEG.
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Huang YJ, Wang H, Gao FB, Li M, Yang H, Wang B, Tai PC. Fluorescein analogues inhibit SecA ATPase: the first sub-micromolar inhibitor of bacterial protein translocation. ChemMedChem 2012; 7:571-7. [PMID: 22354575 DOI: 10.1002/cmdc.201100594] [Citation(s) in RCA: 32] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/18/2011] [Indexed: 11/10/2022]
Abstract
SecA is a central component of the general secretion system that is essential for bacterial growth and thus an ideal target for antimicrobial agents. A series of fluorescein analogues were first screened against the ATPase activity using the truncated unregulated SecA catalytic domain. Rose bengal (RB) and erythrosin B (EB) were found to be potent inhibitors SecA with IC(50) values of 0.5 μM and 2 μM, respectively. RB and EB inhibit the catalytic SecA ATPase more effectively than the F(1) F(0) -proton ATPase. We used three assays to test the effect of these compounds on full-length SecA ATPase: in solution (intrinsic ATPase), in membrane preparation, and translocation ATPase. RB and EB show the following trend in terms of IC(50) values: translocation ATPase<membrane ATPase<intrinsic ATPase. Very importantly, the potency of these fluorescein analogues in inhibiting the truncated SecA ATPase correlates with their ability to inhibit the biologically relevant protein translocation activity of SecA. The in vitro translocation of proOmpA precursors into membrane vesicles is strongly inhibited by RB with IC(50) values of approximately 0.25 μM, making RB the most potent inhibitor of SecA ATPase and SecA-dependent protein translocation reported thus far. The ability of these compounds to inhibit SecA also directly translates into antibacterial effects. Our findings show the value of fluorescein analogues as probes for mechanistic studies of SecA functions and for the potential development of new antimicrobial agents with SecA as the target.
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Affiliation(s)
- Ying-Ju Huang
- Department of Biology, Georgia State University, 490 Petit Science Center, 161 Jesse Hill Jr. Drive, Atlanta, GA 30303, USA
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