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Ji Y, Li J, Liang Y, Li L, Wang Y, Pi L, Xing P, Nomura CT, Chen S, Zhu C, Wang Q. Engineering the Tat-secretion pathway of Bacillus licheniformis for the secretion of cytoplasmic enzyme arginase. Appl Microbiol Biotechnol 2024; 108:89. [PMID: 38194145 DOI: 10.1007/s00253-023-12917-2] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/25/2023] [Revised: 10/06/2023] [Accepted: 10/16/2023] [Indexed: 01/10/2024]
Abstract
The industrial bacterium Bacillus licheniformis has long been used as a microbial factory for the production of enzymes due to its ability to secrete copious amounts of native extracellular proteins and its generally regarded as safe (GRAS) status. However, most attempts to use B. licheniformis to produce heterologous and cytoplasmic enzymes primarily via the general secretory (Sec) pathway have had limited success. The twin-arginine transport (Tat) pathway offers a promising alternative for the extracellular export of Sec-incompatible proteins because it transports full, correctly folded proteins. However, compared to the Sec pathway, the yields of the Tat pathway have historically been too low for commercial use. To improve the export efficiency of the Tat pathway, we identified the optimal Tat-dependent signal peptides and increased the abundance of the Tat translocases, the signal peptidase (SPase), and the intracellular chaperones. These strategic modifications significantly improved the Tat-dependent secretion of the cytoplasmic enzyme arginase into the culture medium using B. licheniformis. The extracellular enzymatic activity of arginase showed a 5.2-fold increase after these modifications. Moreover, compared to the start strain B. licheniformis 0F3, the production of extracellular GFP was improved by 3.8 times using the strategic modified strain B. licheniformis 0F13, and the extracellular enzymatic activity of SOX had a 1.3-fold increase using the strain B. licheniformis 0F14. This Tat-based production chassis has the potential for enhanced production of Sec-incompatible enzymes, therefore expanding the capability of B. licheniformis as an efficient cellular factory for the production of high-value proteins. KEY POINTS: • Systematic genetic modification of Tat-pathway in B. licheniformis. • Significant enhancement of the secretion capacity of Tat pathway for delivery the cytoplasmic enzyme arginase. • A new platform for efficient extracellular production of Sec-incompatible enzymes.
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Affiliation(s)
- Yi Ji
- State Key Laboratory of Biocatalysis and Enzyme Engineering, Environmental Microbial Technology Center of Hubei Province, College of Life Science, Hubei University, Wuhan, 430062, People's Republic of China
| | - Junliang Li
- State Key Laboratory of Biocatalysis and Enzyme Engineering, Environmental Microbial Technology Center of Hubei Province, College of Life Science, Hubei University, Wuhan, 430062, People's Republic of China
| | - Yonglin Liang
- State Key Laboratory of Biocatalysis and Enzyme Engineering, Environmental Microbial Technology Center of Hubei Province, College of Life Science, Hubei University, Wuhan, 430062, People's Republic of China
| | - Liang Li
- State Key Laboratory of Biocatalysis and Enzyme Engineering, Environmental Microbial Technology Center of Hubei Province, College of Life Science, Hubei University, Wuhan, 430062, People's Republic of China
| | - Yajun Wang
- State Key Laboratory of Biocatalysis and Enzyme Engineering, Environmental Microbial Technology Center of Hubei Province, College of Life Science, Hubei University, Wuhan, 430062, People's Republic of China
| | - Li Pi
- Wuhan Grand Hoyo Co., Ltd, Wuhan, 430075, People's Republic of China
| | - Panpan Xing
- Wuhan Grand Hoyo Co., Ltd, Wuhan, 430075, People's Republic of China
| | - Christopher T Nomura
- Department of Biological Sciences, University of Idaho, 875 Perimeter Drive, Moscow, ID, 83844, USA
| | - Shouwen Chen
- State Key Laboratory of Biocatalysis and Enzyme Engineering, Environmental Microbial Technology Center of Hubei Province, College of Life Science, Hubei University, Wuhan, 430062, People's Republic of China
| | - Chengjun Zhu
- Wuhan Grand Hoyo Co., Ltd, Wuhan, 430075, People's Republic of China.
| | - Qin Wang
- State Key Laboratory of Biocatalysis and Enzyme Engineering, Environmental Microbial Technology Center of Hubei Province, College of Life Science, Hubei University, Wuhan, 430062, People's Republic of China.
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Bernal-Cabas M, Miethke M, Antelo-Varela M, Aguilar Suárez R, Neef J, Schön L, Gabarrini G, Otto A, Becher D, Wolf D, van Dijl JM. Functional association of the stress-responsive LiaH protein and the minimal TatAyCy protein translocase in Bacillus subtilis. BIOCHIMICA ET BIOPHYSICA ACTA-MOLECULAR CELL RESEARCH 2020; 1867:118719. [DOI: 10.1016/j.bbamcr.2020.118719] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Received: 10/23/2019] [Revised: 04/07/2020] [Accepted: 04/09/2020] [Indexed: 01/07/2023]
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Abstract
The Tat pathway for protein translocation across bacterial membranes stands out for its selective handling of fully folded cargo proteins. In this review, we provide a comprehensive summary of our current understanding of the different known Tat components, their assembly into different complexes, and their specific roles in the protein translocation process. In particular, this overview focuses on the Gram-negative bacterium Escherichia coli and the Gram-positive bacterium Bacillus subtilis. Using these organisms as examples, we discuss structural features of Tat complexes alongside mechanistic models that allow for the Tat pathway's unique protein proofreading and transport capabilities. Finally, we highlight recent advances in exploiting the Tat pathway for biotechnological benefit, the production of high-value pharmaceutical proteins.
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Abstract
The twin-arginine protein translocation (Tat) system has been characterized in bacteria, archaea and the chloroplast thylakoidal membrane. This system is distinct from other protein transport systems with respect to two key features. Firstly, it accepts cargo proteins with an N-terminal signal peptide that carries the canonical twin-arginine motif, which is essential for transport. Second, the Tat system only accepts and translocates fully folded cargo proteins across the respective membrane. Here, we review the core essential features of folded protein transport via the bacterial Tat system, using the three-component TatABC system of Escherichia coli and the two-component TatAC systems of Bacillus subtilis as the main examples. In particular, we address features of twin-arginine signal peptides, the essential Tat components and how they assemble into different complexes, mechanistic features and energetics of Tat-dependent protein translocation, cytoplasmic chaperoning of Tat cargo proteins, and the remarkable proofreading capabilities of the Tat system. In doing so, we present the current state of our understanding of Tat-dependent protein translocation across biological membranes, which may serve as a lead for future investigations.
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Affiliation(s)
- Kelly M. Frain
- The School of Biosciences, University of Kent, Canterbury, CT2 7NZ UK
| | - Colin Robinson
- The School of Biosciences, University of Kent, Canterbury, CT2 7NZ UK
| | - Jan Maarten van Dijl
- Department of Medical Microbiology, University Medical Center Groningen, University of Groningen (UMCG), Hanzeplein 1, P.O. Box 30001, 9700 RB Groningen, The Netherlands
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Huang X, Cao L, Qin Z, Li S, Kong W, Liu Y. Tat-Independent Secretion of Polyethylene Terephthalate Hydrolase PETase in Bacillus subtilis 168 Mediated by Its Native Signal Peptide. JOURNAL OF AGRICULTURAL AND FOOD CHEMISTRY 2018; 66:13217-13227. [PMID: 30465427 DOI: 10.1021/acs.jafc.8b05038] [Citation(s) in RCA: 57] [Impact Index Per Article: 9.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/09/2023]
Abstract
Widespread utilization of polyethylene terephthalate (PET) has caused critical environmental pollution. The enzymatic degradation of PET is a promising solution to this problem. In this study, PETase, which exhibits much higher PET-hydrolytic activity than other enzymes, was successfully secreted into extracellular milieu from Bacillus subtilis 168 under the direction of its native signal peptide (named SPPETase). SPPETase is predicted to be a twin-arginine signal peptide. Intriguingly, inactivation of twin-arginine translocation (Tat) complexes improved the secretion amount by 3.8-fold, indicating that PETase was exported via Tat-independent pathway. To the best of our knowledge, this is the first report on the improvement of Tat-independent secretion by inactivating Tat components of B. subtilis 168 in LB medium. Furthermore, PET film degradation assay showed that the secreted PETase was fully active. This study paves the first step to construct an efficient engineered strain for PET degradation.
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Affiliation(s)
- Xin Huang
- School of Life Sciences, Institute of Aquatic Economic Animals and Guangdong Provincial Key Laboratory for Aquatic Economic Animals, National Engineering Center for Marine Biotechnology of South China Sea , Sun Yat-Sen University , Guangzhou 510275 , P. R. China
| | - Lichuang Cao
- School of Life Sciences, Institute of Aquatic Economic Animals and Guangdong Provincial Key Laboratory for Aquatic Economic Animals, National Engineering Center for Marine Biotechnology of South China Sea , Sun Yat-Sen University , Guangzhou 510275 , P. R. China
| | - Zongmin Qin
- School of Life Sciences, Institute of Aquatic Economic Animals and Guangdong Provincial Key Laboratory for Aquatic Economic Animals, National Engineering Center for Marine Biotechnology of South China Sea , Sun Yat-Sen University , Guangzhou 510275 , P. R. China
| | - Shuifeng Li
- School of Life Sciences, Institute of Aquatic Economic Animals and Guangdong Provincial Key Laboratory for Aquatic Economic Animals, National Engineering Center for Marine Biotechnology of South China Sea , Sun Yat-Sen University , Guangzhou 510275 , P. R. China
| | - Wei Kong
- School of Life Sciences, Institute of Aquatic Economic Animals and Guangdong Provincial Key Laboratory for Aquatic Economic Animals, National Engineering Center for Marine Biotechnology of South China Sea , Sun Yat-Sen University , Guangzhou 510275 , P. R. China
| | - Yuhuan Liu
- School of Life Sciences, Institute of Aquatic Economic Animals and Guangdong Provincial Key Laboratory for Aquatic Economic Animals, National Engineering Center for Marine Biotechnology of South China Sea , Sun Yat-Sen University , Guangzhou 510275 , P. R. China
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Lucena D, Mauri M, Schmidt F, Eckhardt B, Graumann PL. Microdomain formation is a general property of bacterial membrane proteins and induces heterogeneity of diffusion patterns. BMC Biol 2018; 16:97. [PMID: 30173665 PMCID: PMC6120080 DOI: 10.1186/s12915-018-0561-0] [Citation(s) in RCA: 27] [Impact Index Per Article: 4.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/03/2018] [Accepted: 08/08/2018] [Indexed: 11/22/2022] Open
Abstract
Background Proteins within the cytoplasmic membrane display distinct localization patterns and arrangements. While multiple models exist describing the dynamics of membrane proteins, to date, there have been few systematic studies, particularly in bacteria, to evaluate how protein size, number of transmembrane domains, and temperature affect their diffusion, and if conserved localization patterns exist. Results We have used fluorescence microscopy, single-molecule tracking (SMT), and computer-aided visualization methods to obtain a better understanding of the three-dimensional organization of bacterial membrane proteins, using the model bacterium Bacillus subtilis. First, we carried out a systematic study of the localization of over 200 B. subtilis membrane proteins, tagged with monomeric mVenus-YFP at their original gene locus. Their subcellular localization could be discriminated in polar, septal, patchy, and punctate patterns. Almost 20% of membrane proteins specifically localized to the cell poles, and a vast majority of all proteins localized in distinct structures, which we term microdomains. Dynamics were analyzed for selected membrane proteins, using SMT. Diffusion coefficients of the analyzed transmembrane proteins did not correlate with protein molecular weight, but correlated inversely with the number of transmembrane helices, i.e., transmembrane radius. We observed that temperature can strongly influence diffusion on the membrane, in that upon growth temperature upshift, diffusion coefficients of membrane proteins increased and still correlated inversely to the number of transmembrane domains, following the Saffman–Delbrück relation. Conclusions The vast majority of membrane proteins localized to distinct multimeric assemblies. Diffusion of membrane proteins can be suitably described by discriminating diffusion coefficients into two protein populations, one mobile and one immobile, the latter likely constituting microdomains. Our results show there is high heterogeneity and yet structural order in the cell membrane, and provide a roadmap for our understanding of membrane organization in prokaryotes. Electronic supplementary material The online version of this article (10.1186/s12915-018-0561-0) contains supplementary material, which is available to authorized users.
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Affiliation(s)
- Daniella Lucena
- SYNMIKRO, LOEWE Center for Synthetic Microbiology, Marburg, Germany.,Fachbereich Chemie, Philipps-Universität Marburg, Marburg, Germany
| | - Marco Mauri
- SYNMIKRO, LOEWE Center for Synthetic Microbiology, Marburg, Germany.,INRIA Grenoble - Rhône-Alpes, Montbonnot, France
| | - Felix Schmidt
- SYNMIKRO, LOEWE Center for Synthetic Microbiology, Marburg, Germany.,Fachbereich Physik, Philipps-Universität Marburg, Marburg, Germany
| | - Bruno Eckhardt
- SYNMIKRO, LOEWE Center for Synthetic Microbiology, Marburg, Germany.,Fachbereich Physik, Philipps-Universität Marburg, Marburg, Germany
| | - Peter L Graumann
- SYNMIKRO, LOEWE Center for Synthetic Microbiology, Marburg, Germany. .,Fachbereich Chemie, Philipps-Universität Marburg, Marburg, Germany.
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Unanticipated functional diversity among the TatA-type components of the Tat protein translocase. Sci Rep 2018; 8:1326. [PMID: 29358647 PMCID: PMC5777986 DOI: 10.1038/s41598-018-19640-3] [Citation(s) in RCA: 8] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/21/2017] [Accepted: 12/29/2017] [Indexed: 11/08/2022] Open
Abstract
Twin-arginine translocation (Tat) systems transport folded proteins that harbor a conserved arginine pair in their signal peptides. They assemble from hexahelical TatC-type and single-spanning TatA-type proteins. Many Tat systems comprise two functionally diverse, TatA-type proteins, denominated TatA and TatB. Some bacteria in addition express TatE, which thus far has been characterized as a functional surrogate of TatA. For the Tat system of Escherichia coli we demonstrate here that different from TatA but rather like TatB, TatE contacts a Tat signal peptide independently of the proton-motive force and restricts the premature processing of a Tat signal peptide. Furthermore, TatE embarks at the transmembrane helix five of TatC where it becomes so closely spaced to TatB that both proteins can be covalently linked by a zero-space cross-linker. Our results suggest that in addition to TatB and TatC, TatE is a further component of the Tat substrate receptor complex. Consistent with TatE being an autonomous TatAB-type protein, a bioinformatics analysis revealed a relatively broad distribution of the tatE gene in bacterial phyla and highlighted unique protein sequence features of TatE orthologs.
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8
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Hohmann HP, van Dijl JM, Krishnappa L, Prágai Z. Host Organisms:Bacillus subtilis. Ind Biotechnol (New Rochelle N Y) 2016. [DOI: 10.1002/9783527807796.ch7] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/29/2022] Open
Affiliation(s)
- Hans-Peter Hohmann
- Nutrition Innovation Center R&D Biotechnology; DSM Nutritional Products Ltd; Wurmisweg 576 CH-4303 Kaiseraugst Switzerland
| | - Jan M. van Dijl
- University of Groningen, University Medical Center Groningen; Department of Medical Microbiology; Hanzeplein 1 9700 RB Groningen The Netherlands
| | - Laxmi Krishnappa
- University of Groningen, University Medical Center Groningen; Department of Medical Microbiology; Hanzeplein 1 9700 RB Groningen The Netherlands
| | - Zoltán Prágai
- Nutrition Innovation Center R&D Biotechnology; DSM Nutritional Products Ltd; Wurmisweg 576 CH-4303 Kaiseraugst Switzerland
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9
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Abstract
Twin-arginine protein translocation systems (Tat) translocate fully folded and co-factor-containing proteins across biological membranes. In this review, we focus on the Tat pathway of Gram-positive bacteria. The minimal Tat pathway is composed of two components, namely a TatA and TatC pair, which are often complemented with additional TatA-like proteins. We provide overviews of our current understanding of Tat pathway composition and mechanistic aspects related to Tat-dependent cargo protein translocation. This includes Tat pathway flexibility, requirements for the correct folding and incorporation of co-factors in cargo proteins and the functions of known cargo proteins. Tat pathways of several Gram-positive bacteria are discussed in detail, with emphasis on the Tat pathway of Bacillus subtilis. We discuss both shared and unique features of the different Gram-positive bacterial Tat pathways. Lastly, we highlight topics for future research on Tat, including the development of this protein transport pathway for the biotechnological secretion of high-value proteins and its potential applicability as an antimicrobial drug target in pathogens.
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Affiliation(s)
- Vivianne J Goosens
- MRC Centre for Molecular Bacteriology and Infection, Section of Microbiology, Imperial College London, London, SW7 2AZ, UK
| | - Jan Maarten van Dijl
- Department of Medical Microbiology, University of Groningen, University Medical Center Groningen, Hanzeplein 1, P.O. Box 30001, 9700, RB, Groningen, The Netherlands.
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10
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A Tat ménage à trois — The role of Bacillus subtilis TatAc in twin-arginine protein translocation. BIOCHIMICA ET BIOPHYSICA ACTA-MOLECULAR CELL RESEARCH 2015; 1853:2745-53. [DOI: 10.1016/j.bbamcr.2015.07.022] [Citation(s) in RCA: 16] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Received: 05/18/2015] [Revised: 07/28/2015] [Accepted: 07/30/2015] [Indexed: 11/19/2022]
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11
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Optimization of the secretion pathway for heterologous proteins in Bacillus subtilis. BIOTECHNOL BIOPROC E 2015. [DOI: 10.1007/s12257-014-0843-5] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/23/2022]
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12
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Goosens VJ, Monteferrante CG, van Dijl JM. Co-factor insertion and disulfide bond requirements for twin-arginine translocase-dependent export of the Bacillus subtilis Rieske protein QcrA. J Biol Chem 2014; 289:13124-31. [PMID: 24652282 DOI: 10.1074/jbc.m113.529677] [Citation(s) in RCA: 13] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/06/2022] Open
Abstract
The twin-arginine translocation (Tat) pathway can transport folded and co-factor-containing cargo proteins over bacterial cytoplasmic membranes. Functional Tat machinery components, a folded state of the cargo protein and correct co-factor insertion in the cargo protein are generally considered as prerequisites for successful translocation. The present studies were aimed at a dissection of these requirements with regard to the Rieske iron-sulfur protein QcrA of Bacillus subtilis. Notably, QcrA is a component of the cytochrome bc1 complex, which is conserved from bacteria to man. Single amino acid substitutions were introduced into the Rieske domain of QcrA to prevent either co-factor binding or disulfide bond formation. Both types of mutations precluded QcrA translocation. Importantly, a proofreading hierarchy was uncovered, where a QcrA mutant defective in disulfide bonding was quickly degraded, whereas mutant QcrA proteins defective in co-factor binding accumulated in the cytoplasm and membrane. Altogether, these are the first studies on Tat-dependent protein translocation where both oxidative folding and co-factor attachment have been addressed in a single native molecule.
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Affiliation(s)
- Vivianne J Goosens
- From the Department of Medical Microbiology, University of Groningen, University Medical Center Groningen, Hanzeplein 1, P. O. Box 30001, 9700 RB, Groningen, The Netherlands
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The canonical twin-arginine translocase components are not required for secretion of folded green fluorescent protein from the ancestral strain of Bacillus subtilis. Appl Environ Microbiol 2014; 80:3219-32. [PMID: 24632256 DOI: 10.1128/aem.00335-14] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022] Open
Abstract
Cellular processes, such as the digestion of macromolecules, phosphate acquisition, and cell motility, require bacterial secretion systems. In Bacillus subtilis, the predominant protein export pathways are Sec (generalized secretory pathway) and Tat (twin-arginine translocase). Unlike Sec, which secretes unfolded proteins, the Tat machinery secretes fully folded proteins across the plasma membrane and into the medium. Proteins are directed for Tat-dependent export by N-terminal signal peptides that contain a conserved twin-arginine motif. Thus, utilizing the Tat secretion system by fusing a Tat signal peptide is an attractive strategy for the production and export of heterologous proteins. As a proof of concept, we expressed green fluorescent protein (GFP) fused to the PhoD Tat signal peptide in the laboratory and ancestral strains of B. subtilis. Secretion of the Tat-GFP construct, as well as secretion of proteins in general, was substantially increased in the ancestral strain. Furthermore, our results show that secreted, fluorescent GFP could be purified directly from the extracellular medium. Nonetheless, export was not dependent on the known Tat secretion components or the signal peptide twin-arginine motif. We propose that the ancestral strain contains additional Tat components and/or secretion regulators that were abrogated following domestication.
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Patel R, Smith SM, Robinson C. Protein transport by the bacterial Tat pathway. BIOCHIMICA ET BIOPHYSICA ACTA-MOLECULAR CELL RESEARCH 2014; 1843:1620-8. [PMID: 24583120 DOI: 10.1016/j.bbamcr.2014.02.013] [Citation(s) in RCA: 38] [Impact Index Per Article: 3.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 12/06/2013] [Revised: 02/10/2014] [Accepted: 02/15/2014] [Indexed: 10/25/2022]
Abstract
The twin-arginine translocation (Tat) system accomplishes the remarkable feat of translocating large - even dimeric - proteins across tightly sealed energy-transducing membranes. All of the available evidence indicates that it is unique in terms of both structure and mechanism; however its very nature has hindered efforts to probe the core translocation events. At the heart of the problem is the fact that two large sub-complexes are believed to coalesce to form the active translocon, and 'capturing' this translocation event has been too difficult. Nevertheless, studies on the individual components have come a long way in recent years, and structural studies have reached the point where educated guesses can be made concerning the most interesting aspects of Tat. In this article we review these studies and the emerging ideas in this field. 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)
- Roshani Patel
- School of Life Sciences, University of Warwick, Coventry CV4 7AL, United Kingdom
| | - Sarah M Smith
- School of Life Sciences, University of Warwick, Coventry CV4 7AL, United Kingdom
| | - Colin Robinson
- Centre for Molecular Processing, School of Biosciences, University of Kent, Canterbury CT2 7NJ, United Kingdom.
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15
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Goosens VJ, Monteferrante CG, van Dijl JM. The Tat system of Gram-positive bacteria. BIOCHIMICA ET BIOPHYSICA ACTA-MOLECULAR CELL RESEARCH 2013; 1843:1698-706. [PMID: 24140208 DOI: 10.1016/j.bbamcr.2013.10.008] [Citation(s) in RCA: 60] [Impact Index Per Article: 5.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 07/07/2013] [Revised: 10/08/2013] [Accepted: 10/08/2013] [Indexed: 10/26/2022]
Abstract
The twin-arginine protein translocation (Tat) system has a unique ability to translocate folded and co-factor-containing proteins across lipid bilayers. The Tat pathway is present in bacteria, archaea and in the thylakoid membranes of chloroplasts and, depending on the organism and environmental conditions, it can be deemed important for cell survival, virulence or bioproduction. This review provides an overview of the current understanding of the Tat system with specific focus on Gram-positive bacteria. The 'universal minimal Tat system' is composed of a TatA and a TatC protein. However, this pathway is more commonly composed of two TatA-like proteins and one TatC protein. Often the TatA-like proteins have diverged to have two different functions and, in this case, the second TatA-like protein is usually referred to as TatB. The correct folding and/or incorporation of co-factors are requirements for translocation, and the known quality control mechanisms are examined in this review. A number of examples of crosstalk between the Tat system and other protein transport systems, such as the Sec-YidC translocon and signal peptidases or sheddases are also discussed. Further, an overview of specific Gram-positive bacterial Tat systems found in monoderm and diderm species is detailed. Altogether, this review highlights the unique features of Gram-positive bacterial Tat systems and pinpoints key questions that remain to be addressed in future research. 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)
- Vivianne J Goosens
- Department of Medical Microbiology, University of Groningen, University Medical Center Groningen, Hanzeplein 1, P.O. Box 30001, 9700 RB Groningen, The Netherlands
| | - Carmine G Monteferrante
- Department of Medical Microbiology, University of Groningen, University Medical Center Groningen, Hanzeplein 1, P.O. Box 30001, 9700 RB Groningen, The Netherlands
| | - Jan Maarten van Dijl
- Department of Medical Microbiology, University of Groningen, University Medical Center Groningen, Hanzeplein 1, P.O. Box 30001, 9700 RB Groningen, The Netherlands.
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16
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Albiniak AM, Matos CFRO, Branston SD, Freedman RB, Keshavarz-Moore E, Robinson C. High-level secretion of a recombinant protein to the culture medium with a Bacillus subtilis twin-arginine translocation system in Escherichia coli. FEBS J 2013; 280:3810-21. [PMID: 23745597 DOI: 10.1111/febs.12376] [Citation(s) in RCA: 17] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/31/2013] [Revised: 05/10/2013] [Accepted: 05/15/2013] [Indexed: 11/29/2022]
Abstract
The twin-arginine translocation (Tat) system transports folded proteins across the plasma membrane in bacteria, and heterologous proteins can be exported by this pathway if a Tat-type signal peptide is present at the N-terminus. The system thus has potential for biopharmaceutical production in Escherichia coli, where export to the periplasm is often a favoured approach. Previous studies have shown that E. coli cells can export high levels of protein by the Tat pathway, and the protein product accummulates almost exclusively in the periplasm. In this study, we analysed E. coli cells that express the Bacillus subtilis TatAdCd system in place of the native TatABC system. We show that a heterologous model protein, comprising the TorA signal peptide linked to green fluorescent protein (TorA-GFP), is efficiently exported by the TatAdCd system. However, whereas the GFP is exported initially to the periplasm during batch fermentation, the mature protein is increasingly found in the extracellular culture medium. By the end of a 16-h fermentation, ~ 90% of exported GFP is present in the medium as active mature protein. The total protein profiles of the medium and periplasm are essentially identical, confirming that the outer membrane becomes leaky during the fermentation process. The cells are otherwise intact, and there is no large-scale release of cytoplasmic contents. Export levels are relatively high, with ~ 0.35 g GFP·L⁻¹ culture present in the medium. This system thus offers a means of producing recombinant protein in E. coli and harvesting directly from the medium, with potential advantages in terms of ease of purification and downstream processing.
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Affiliation(s)
- Anna M Albiniak
- School of Life Sciences, University of Warwick, Coventry, UK
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17
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Beck D, Vasisht N, Baglieri J, Monteferrante CG, van Dijl JM, Robinson C, Smith CJ. Ultrastructural characterisation of Bacillus subtilis TatA complexes suggests they are too small to form homooligomeric translocation pores. BIOCHIMICA ET BIOPHYSICA ACTA-MOLECULAR CELL RESEARCH 2013; 1833:1811-9. [PMID: 23567937 PMCID: PMC3988878 DOI: 10.1016/j.bbamcr.2013.03.028] [Citation(s) in RCA: 16] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 02/05/2013] [Revised: 03/27/2013] [Accepted: 03/28/2013] [Indexed: 11/29/2022]
Abstract
Tat-dependent protein transport permits the traffic of fully folded proteins across membranes in bacteria and chloroplasts. The mechanism by which this occurs is not understood. Current theories propose that a key step requires the coalescence of a substrate-binding TatC-containing complex with a TatA complex, which forms pores of varying sizes that could accommodate different substrates. We have studied the structure of the TatAd complex from Bacillus subtilis using electron microscopy to generate the first 3D model of a TatA complex from a Gram-positive bacterium. We observe that TatAd does not exhibit the remarkable heterogeneity of Escherichia coli TatA complexes but instead forms ring-shaped complexes of 7.5–9 nm diameter with potential pores of 2.5–3 nm diameter that are occluded at one end. Such structures are consistent with those seen for E. coli TatE complexes. Furthermore, the small diameter of the TatAd pore, and the homogeneous nature of the complexes, suggest that TatAd cannot form the translocation channel by itself. Biochemical data indicate that another B. subtilis TatA complex, TatAc, has similar properties, suggesting a common theme for TatA-type complexes from Bacillus. First 3D density maps of TatA-type complexes from Gram-positive organism TatAd forms ring-shaped complexes with potential pores of 2.5–3 nm diameters. The small diameter of TatAd channels apparently precludes passage of folded proteins. TatAc forms homogeneous complexes of < 100 kDa. Similarities between B. subtilis TatAd and TatAc suggest a common mechanism.
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Affiliation(s)
- Daniel Beck
- School of Life Sciences, University of Warwick, Coventry CV4 7AL, UK
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Freudl R. Leaving home ain't easy: protein export systems in Gram-positive bacteria. Res Microbiol 2013; 164:664-74. [PMID: 23541477 DOI: 10.1016/j.resmic.2013.03.014] [Citation(s) in RCA: 33] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/16/2012] [Accepted: 02/05/2013] [Indexed: 10/27/2022]
Abstract
Transport of proteins into or across biological membranes is catalyzed by membrane-bound transport machineries. In Gram-positive bacteria, the vast majority of proteins are exported out of the cytosol by the conserved general secretion (Sec) system or, alternatively, by the twin-arginine translocation (Tat) system, that closely resemble their well-studied counterparts in Gram-negative bacteria. Besides these common major export routes, additional unique protein export systems (such as accessory Sec2 systems and/or type VII/WXG100 secretion systems) exist in some Gram-positive bacteria that are specifically involved in the secretion of limited subsets of proteins.
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Affiliation(s)
- Roland Freudl
- Institut für Bio- und Geowissenschaften 1, Biotechnologie, Forschungszentrum Jülich GmbH, D-52425 Jülich, Germany.
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19
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Monteferrante CG, MacKichan C, Marchadier E, Prejean MV, Carballido-López R, van Dijl JM. Mapping the twin-arginine protein translocation network of Bacillus subtilis. Proteomics 2013. [PMID: 23180473 DOI: 10.1002/pmic.201200416] [Citation(s) in RCA: 15] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/05/2022]
Abstract
Bacteria employ twin-arginine translocation (Tat) pathways for the transport of folded proteins to extracytoplasmic destinations. In recent years, most studies on bacterial Tat pathways addressed the membrane-bound TatA(B)C subunits of the Tat translocase, and the specific interactions between this translocase and its substrate proteins. In contrast, relatively few studies investigated possible coactors in the TatA(B)C-dependent protein translocation process. The present studies were aimed at identifying interaction partners of the Tat pathway of Bacillus subtilis, which is a paradigm for studies on protein secretion by Gram-positive bacteria. Specifically, 36 interaction partners of the TatA and TatC subunits were identified by rigorous application of the yeast two-hybrid (Y2H) approach. Our Y2H analyses revealed that the three TatA isoforms of B. subtilis can form homo- and heterodimers. Subsequently, the secretion of the Tat substrates YwbN and PhoD was tested in mutant strains lacking genes for the TatAC interaction partners identified in our genome-wide Y2H screens. Our results show that the cell wall-bound protease WprA is important for YwbN secretion, and that the HemAT and CsbC proteins are required for PhoD secretion under phosphate starvation conditions. Taken together, our findings imply that the Bacillus Tat pathway is embedded in an intricate protein-protein interaction network.
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Affiliation(s)
- Carmine G Monteferrante
- Department of Medical Microbiology, University of Groningen, University Medical Center Groningen, Groningen, the Netherlands
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Goosens VJ, Otto A, Glasner C, Monteferrante CC, van der Ploeg R, Hecker M, Becher D, van Dijl JM. Novel Twin-Arginine Translocation Pathway-Dependent Phenotypes of Bacillus subtilis Unveiled by Quantitative Proteomics. J Proteome Res 2013; 12:796-807. [DOI: 10.1021/pr300866f] [Citation(s) in RCA: 24] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
Affiliation(s)
- Vivianne J. Goosens
- Department of Medical Microbiology, University of Groningen, University Medical Center
Groningen, Hanzeplein 1, P.O. Box 30001, 9700 RB Groningen, The Netherlands
| | - Andreas Otto
- Institut für Mikrobiologie, Ernst-Moritz-Arndt Universität Greifswald, Friedrich-Ludwig-Jahn-Str.
15, D-17489 Greifswald, Germany
| | - Corinna Glasner
- Department of Medical Microbiology, University of Groningen, University Medical Center
Groningen, Hanzeplein 1, P.O. Box 30001, 9700 RB Groningen, The Netherlands
| | - Carmine C. Monteferrante
- Department of Medical Microbiology, University of Groningen, University Medical Center
Groningen, Hanzeplein 1, P.O. Box 30001, 9700 RB Groningen, The Netherlands
| | - René van der Ploeg
- Department of Medical Microbiology, University of Groningen, University Medical Center
Groningen, Hanzeplein 1, P.O. Box 30001, 9700 RB Groningen, The Netherlands
| | - Michael Hecker
- Institut für Mikrobiologie, Ernst-Moritz-Arndt Universität Greifswald, Friedrich-Ludwig-Jahn-Str.
15, D-17489 Greifswald, Germany
| | - Dörte Becher
- Institut für Mikrobiologie, Ernst-Moritz-Arndt Universität Greifswald, Friedrich-Ludwig-Jahn-Str.
15, D-17489 Greifswald, Germany
| | - Jan Maarten van Dijl
- Department of Medical Microbiology, University of Groningen, University Medical Center
Groningen, Hanzeplein 1, P.O. Box 30001, 9700 RB Groningen, The Netherlands
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