1
|
Xiao H, Zou Y, Wang J, Wan S. A Review for Artificial Intelligence Based Protein Subcellular Localization. Biomolecules 2024; 14:409. [PMID: 38672426 PMCID: PMC11048326 DOI: 10.3390/biom14040409] [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: 02/29/2024] [Revised: 03/21/2024] [Accepted: 03/25/2024] [Indexed: 04/28/2024] Open
Abstract
Proteins need to be located in appropriate spatiotemporal contexts to carry out their diverse biological functions. Mislocalized proteins may lead to a broad range of diseases, such as cancer and Alzheimer's disease. Knowing where a target protein resides within a cell will give insights into tailored drug design for a disease. As the gold validation standard, the conventional wet lab uses fluorescent microscopy imaging, immunoelectron microscopy, and fluorescent biomarker tags for protein subcellular location identification. However, the booming era of proteomics and high-throughput sequencing generates tons of newly discovered proteins, making protein subcellular localization by wet-lab experiments a mission impossible. To tackle this concern, in the past decades, artificial intelligence (AI) and machine learning (ML), especially deep learning methods, have made significant progress in this research area. In this article, we review the latest advances in AI-based method development in three typical types of approaches, including sequence-based, knowledge-based, and image-based methods. We also elaborately discuss existing challenges and future directions in AI-based method development in this research field.
Collapse
Affiliation(s)
- Hanyu Xiao
- Department of Genetics, Cell Biology and Anatomy, College of Medicine, University of Nebraska Medical Center, Omaha, NE 68198, USA;
| | - Yijin Zou
- College of Veterinary Medicine, China Agricultural University, Beijing 100193, China;
| | - Jieqiong Wang
- Department of Neurological Sciences, College of Medicine, University of Nebraska Medical Center, Omaha, NE 68198, USA;
| | - Shibiao Wan
- Department of Genetics, Cell Biology and Anatomy, College of Medicine, University of Nebraska Medical Center, Omaha, NE 68198, USA;
| |
Collapse
|
2
|
Chew NSL, Ooi CW, Yeo LY, Tan MK. Influence of MHz-order acoustic waves on bacterial suspensions. ULTRASONICS 2024; 138:107234. [PMID: 38171227 DOI: 10.1016/j.ultras.2023.107234] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 09/18/2023] [Revised: 11/22/2023] [Accepted: 12/24/2023] [Indexed: 01/05/2024]
Abstract
The development of alternative techniques to efficiently inactivate bacterial suspensions is crucial to prevent transmission of waterborne illness, particularly when commonly used techniques such as heating, filtration, chlorination, or ultraviolet treatment are not practical or feasible. We examine the effect of MHz-order acoustic wave irradiation in the form of surface acoustic waves (SAWs) on Gram-positive (Escherichia coli) and Gram-negative (Brevibacillus borstelensis and Staphylococcus aureus) bacteria suspended in water droplets. A significant increase in the relative bacterial load reduction of colony-forming units (up to 74%) can be achieved by either increasing (1) the excitation power, or, (2) the acoustic treatment duration, which we attributed to the effect of the acoustic radiation force exerted on the bacteria. Consequently, by increasing the maximum pressure amplitude via a hybrid modulation scheme involving a combination of amplitude and pulse-width modulation, we observe that the bacterial inactivation efficiency can be further increased by approximately 14%. By combining this scalable acoustic-based bacterial inactivation platform with plasma-activated water, a 100% reduction in E. coli is observed in less than 10 mins, therefore demonstrating the potential of the synergistic effects of MHz-order acoustic irradiation and plasma-activated water as an efficient strategy for water decontamination.
Collapse
Affiliation(s)
- Nicholas S L Chew
- Department of Mechanical Engineering, School of Engineering, Monash University Malaysia, 47500 Bandar Sunway, Selangor, Malaysia
| | - Chien W Ooi
- Department of Chemical Engineering, School of Engineering, Monash University Malaysia, 47500 Bandar Sunway, Selangor, Malaysia
| | - Leslie Y Yeo
- Micro/Nanophysics Research Laboratory, RMIT University, Melbourne, VIC 3001, Australia
| | - Ming K Tan
- Department of Mechanical Engineering, School of Engineering, Monash University Malaysia, 47500 Bandar Sunway, Selangor, Malaysia.
| |
Collapse
|
3
|
Naka S, Matsuoka D, Goto K, Misaki T, Nagasawa Y, Ito S, Nomura R, Nakano K, Matsumoto-Nakano M. Cnm of Streptococcus mutans is important for cell surface structure and membrane permeability. Front Cell Infect Microbiol 2022; 12:994014. [PMID: 36176579 PMCID: PMC9513430 DOI: 10.3389/fcimb.2022.994014] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/14/2022] [Accepted: 08/18/2022] [Indexed: 11/18/2022] Open
Abstract
Streptococcus mutans, a Gram-positive facultative anaerobic bacterium, is a major pathogen of dental caries. The protein Cnm of S. mutans is involved in collagen binding, but its other biological functions are unknown. In this study, a Cnm-deficient isogenic mutant and a complementation strain were generated from a Cnm-positive S. mutans strain to help determine the properties of Cnm. Initially, comparison of the cell surface structure was performed by electron microscopy, which demonstrated that Cnm appears to be localized on the cell surface and associated with a protruding cell surface structure. Deep RNA sequencing of the strains revealed that the defect in Cnm caused upregulated expression of many genes related to ABC transporters and cell-surface proteins, while a few genes were downregulated. The amount of biofilm formed by the Cnm-defective strain increased compared with the parental and complemented strains, but the biofilm structure was thinner because of elevated expression of genes encoding glucan synthesis enzymes, leading to increased production of extracellular polysaccharides. Particular antibiotics, including bacitracin and chloramphenicol, had a lower minimum inhibitory concentration for the Cnm-defective strain than particular antibiotics, including bacitracin and chloramphenicol, compared with the parental and complemented strains. Our results suggest that S. mutans Cnm is located on the cell surface, gives rise to the observed protruding cell surface, and is associated with several biological properties related to membrane permeability.
Collapse
Affiliation(s)
- Shuhei Naka
- Department of Pediatric Dentistry, Okayama University Graduate School of Medicine, Dentistry and Pharmaceutical Sciences, Okayama, Japan
| | - Daiki Matsuoka
- Department of Pediatric Dentistry, Okayama University Graduate School of Medicine, Dentistry and Pharmaceutical Sciences, Okayama, Japan
| | - Kana Goto
- Department of Pediatric Dentistry, Okayama University Graduate School of Medicine, Dentistry and Pharmaceutical Sciences, Okayama, Japan
| | - Taro Misaki
- Division of Nephrology, Seirei Hamamatsu General Hospital, Hamamatsu, Japan
- Department of Nursing, Faculty of Nursing, Seirei Christopher University, Hamamatsu, Japan
| | - Yasuyuki Nagasawa
- Department of General Internal Medicine, Hyogo College of Medicine, Nishinomiya, Japan
| | - Seigo Ito
- Department of Internal Medicine, Japan Self-Defense Iruma Hospital, Iruma, Japan
| | - Ryota Nomura
- Department of Pediatric Dentistry, Division of Oral infection and Disease Control, Osaka University Graduate School of Dentistry, Suita, Japan
| | - Kazuhiko Nakano
- Department of Pediatric Dentistry, Division of Oral infection and Disease Control, Osaka University Graduate School of Dentistry, Suita, Japan
| | - Michiyo Matsumoto-Nakano
- Department of Pediatric Dentistry, Okayama University Graduate School of Medicine, Dentistry and Pharmaceutical Sciences, Okayama, Japan
- *Correspondence: Michiyo Matsumoto-Nakano,
| |
Collapse
|
4
|
Wall Teichoic Acids Facilitate the Release of Toxins from the Surface of Staphylococcus aureus. Microbiol Spectr 2022; 10:e0101122. [PMID: 35863033 PMCID: PMC9430763 DOI: 10.1128/spectrum.01011-22] [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] [Indexed: 11/20/2022] Open
Abstract
A major feature of the pathogenicity of Staphylococcus aureus is its ability to secrete cytolytic toxins. This process involves the translocation of the toxins from the cytoplasm through the bacterial membrane and the cell wall to the external environment. The process of their movement through the membrane is relatively well defined, involving both general and toxin-specific secretory systems. Movement of the toxins through the cell wall was considered to involve the passive diffusion of the proteins through the porous cell wall structures; however, recent work suggests that this is more complex, and here we demonstrate a role for the wall teichoic acids (WTA) in this process. Utilizing a genome-wide association approach, we identified a polymorphism in the locus encoding the WTA biosynthetic machinery as associated with the cytolytic activity of the bacteria. We verified this association using an isogenic mutant set and found that WTA are required for the release of several cytolytic toxins from the bacterial cells. We show that this effect is mediated by a change in the electrostatic charge across the cell envelope that results from the loss of WTA. As a major target for the development of novel therapeutics, it is important that we fully understand the entire process of cytolytic toxin production and release. These findings open up a new aspect to the process of toxin release by a major human pathogen while also demonstrating that clinical isolates can utilize WTA production to vary their cytotoxicity, thereby altering their pathogenic capabilities. IMPORTANCE The production and release of cytolytic toxins is a critical aspect for the pathogenicity of many bacterial pathogens. In this study, we demonstrate a role for wall teichoic acids, molecules that are anchored to the peptidoglycan of the bacterial cell wall, in the release of toxins from S. aureus cells into the extracellular environment. Our findings suggest that this effect is mediated by a gradient of electrostatic charge which the presence of the negatively charged WTA molecules create across the cell envelope. This work brings an entirely new aspect to our understanding of the cytotoxicity of S. aureus and demonstrates a further means by which this major human pathogen can adapt its pathogenic capabilities.
Collapse
|
5
|
Mayer J, Knuuti T, Baumgarten L, Menke E, Bischoff L, Bunk B, Biedendieck R. Construction and Application of a Plasmid-Based Signal Peptide Library for Improved Secretion of Recombinant Proteins with Priestia megaterium. Microorganisms 2022; 10:microorganisms10040777. [PMID: 35456829 PMCID: PMC9032162 DOI: 10.3390/microorganisms10040777] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/17/2022] [Revised: 03/31/2022] [Accepted: 04/01/2022] [Indexed: 02/04/2023] Open
Abstract
The secretion of recombinant proteins plays an important role in their economic production and purification. The secretion efficiency depends on the responsible signal peptide (SP) in combination with the target protein and the given host and cannot be predicted so far. Due to its high plasmid stability, the lack of alkaline extracellular proteases and only few contaminating extracellular host proteins, Priestia megaterium provides a promising alternative to common Bacillus species. For the development of an easy and fast cloning and screening system to identify the SP best suited to a distinct protein, a plasmid-based SP library containing all predicted 182 Sec-dependent SPs from P. megaterium was established. The splitting of the SPs into 10 groups of individual multi-SP plasmids (pMSPs) allows their grouped amplification and application in screening approaches. The functionality of the whole library was demonstrated by enhancing the amount of the already well-secreted α-amylase AmyE by 1.6-fold. The secretion of a novel penicillin G acylase, which remained as insoluble protein inside the cells, as its native SP is unsuitable for secretion in P. megaterium, could be enhanced even up to 29-fold. Overall, only around 170 recombinant P. megaterium clones based on 50 inserted SPs had to be screened to achieve sufficient amounts for further enzyme characterizations. Thus, this newly developed plasmid-based genetic tool applicable for P. megaterium and also other Bacillus species facilitates the identification of suitable SPs for secretion of recombinant proteins.
Collapse
Affiliation(s)
- Janine Mayer
- Institute of Microbiology and Braunschweig Integrated Centre of Systems Biology (BRICS), Technische Universität Braunschweig, Rebenring 56, 38106 Braunschweig, Germany; (J.M.); (T.K.); (L.B.); (E.M.); (L.B.)
| | - Tobias Knuuti
- Institute of Microbiology and Braunschweig Integrated Centre of Systems Biology (BRICS), Technische Universität Braunschweig, Rebenring 56, 38106 Braunschweig, Germany; (J.M.); (T.K.); (L.B.); (E.M.); (L.B.)
| | - Lisa Baumgarten
- Institute of Microbiology and Braunschweig Integrated Centre of Systems Biology (BRICS), Technische Universität Braunschweig, Rebenring 56, 38106 Braunschweig, Germany; (J.M.); (T.K.); (L.B.); (E.M.); (L.B.)
| | - Elise Menke
- Institute of Microbiology and Braunschweig Integrated Centre of Systems Biology (BRICS), Technische Universität Braunschweig, Rebenring 56, 38106 Braunschweig, Germany; (J.M.); (T.K.); (L.B.); (E.M.); (L.B.)
| | - Lena Bischoff
- Institute of Microbiology and Braunschweig Integrated Centre of Systems Biology (BRICS), Technische Universität Braunschweig, Rebenring 56, 38106 Braunschweig, Germany; (J.M.); (T.K.); (L.B.); (E.M.); (L.B.)
| | - Boyke Bunk
- Leibniz Institute DSMZ-German Collection of Microorganisms and Cell Cultures, Inhoffenstraße 7, 38124 Braunschweig, Germany;
| | - Rebekka Biedendieck
- Institute of Microbiology and Braunschweig Integrated Centre of Systems Biology (BRICS), Technische Universität Braunschweig, Rebenring 56, 38106 Braunschweig, Germany; (J.M.); (T.K.); (L.B.); (E.M.); (L.B.)
- Correspondence: ; Tel.: +49-531-391-55291
| |
Collapse
|
6
|
Zhao D, Zhang R, Liu X, Li X, Xu M, Huang X, Xiao X. Screening of Chitosan Derivatives-Carbon Dots Based on Antibacterial Activity and Application in Anti-Staphylococcus aureus Biofilm. Int J Nanomedicine 2022; 17:937-952. [PMID: 35280335 PMCID: PMC8904944 DOI: 10.2147/ijn.s350739] [Citation(s) in RCA: 2] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/22/2021] [Accepted: 02/10/2022] [Indexed: 12/15/2022] Open
Abstract
Introduction Pathogenic bacteria, especially the ones with highly organized, systematic aggregating bacteria biofilm, would cause great harm to human health. The development of highly efficient antibacterial and antibiofilm functional fluorescent nanomaterial would be of great significance. Methods This paper reports the preparation of a series of antibacterial functional carbon dots (CDs) with chitosan (CS) and its derivatives as raw materials through one-step route, and the impact of various experiment parameters upon the optical properties and the antibacterial abilities have been explored, including the structures of the raw materials, excipients, and solvents. Results The CDs prepared by quaternary ammonium salt of chitosan (QCS) and ethylenediamine (EDA) exhibit multiple antibacterial effects through membrane breaking, DNA and protein destroying, and the production of singlet oxygen. The CDs showed excellent broad-spectrum inhibitory activity against a variety of bacteria (Gram-positive and negative bacteria), in particular, to the biofilm of Staphylococcus aureus with minimum inhibitory concentration at 10 µg/mL, showing great potential in killing bacteria and biofilms. The biocompatibility experiments proved that QCS-EDA-CDs are non-toxic to human normal hepatocytes and have low haemolytic effect. Furthermore, the prepared QCS-EDA-CDs have been successfully used in bacterial and biofilm imaging thanks to their excellent optical properties. Conclusion This paper explored the preparation and application of functional CDs, which can be used as the visual probe and therapeutic agents in the treatment of infections caused by bacteria and biofilm.
Collapse
Affiliation(s)
- Dan Zhao
- School of Pharmaceutical Sciences, South-Central University for Nationalities, Wuhan, 430074, People’s Republic of China
- National Demonstration Center for Experimental Ethnopharmacology Education (South-Central University for Nationalities), Wuhan, 430065, People’s Republic of China
- Correspondence: Dan Zhao, Tel +1 806 208 4690, Email
| | - Rui Zhang
- School of Pharmaceutical Sciences, South-Central University for Nationalities, Wuhan, 430074, People’s Republic of China
- National Demonstration Center for Experimental Ethnopharmacology Education (South-Central University for Nationalities), Wuhan, 430065, People’s Republic of China
| | - Xuemei Liu
- School of Pharmaceutical Sciences, South-Central University for Nationalities, Wuhan, 430074, People’s Republic of China
- National Demonstration Center for Experimental Ethnopharmacology Education (South-Central University for Nationalities), Wuhan, 430065, People’s Republic of China
| | - Xiaoyun Li
- School of Pharmaceutical Sciences, South-Central University for Nationalities, Wuhan, 430074, People’s Republic of China
- National Demonstration Center for Experimental Ethnopharmacology Education (South-Central University for Nationalities), Wuhan, 430065, People’s Republic of China
| | - Mengyu Xu
- School of Pharmaceutical Sciences, South-Central University for Nationalities, Wuhan, 430074, People’s Republic of China
- National Demonstration Center for Experimental Ethnopharmacology Education (South-Central University for Nationalities), Wuhan, 430065, People’s Republic of China
| | - Xianju Huang
- School of Pharmaceutical Sciences, South-Central University for Nationalities, Wuhan, 430074, People’s Republic of China
- National Demonstration Center for Experimental Ethnopharmacology Education (South-Central University for Nationalities), Wuhan, 430065, People’s Republic of China
| | - Xincai Xiao
- School of Pharmaceutical Sciences, South-Central University for Nationalities, Wuhan, 430074, People’s Republic of China
- National Demonstration Center for Experimental Ethnopharmacology Education (South-Central University for Nationalities), Wuhan, 430065, People’s Republic of China
| |
Collapse
|
7
|
Pourhassan N Z, Smits SHJ, Ahn JH, Schmitt L. Biotechnological applications of type 1 secretion systems. Biotechnol Adv 2021; 53:107864. [PMID: 34767962 DOI: 10.1016/j.biotechadv.2021.107864] [Citation(s) in RCA: 8] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/18/2021] [Revised: 10/30/2021] [Accepted: 10/31/2021] [Indexed: 02/06/2023]
Abstract
Bacteria have evolved a diverse range of secretion systems to export different substrates across their cell envelope. Although secretion of proteins into the extracellular space could offer advantages for recombinant protein production, the low secretion titers of the secretion systems for some heterologous proteins remain a clear drawback of their utility at commercial scales. Therefore, a potential use of most of secretion systems as production platforms at large scales are still limited. To overcome this limitation, remarkable efforts have been made toward improving the secretion efficiency of different bacterial secretion systems in recent years. Here, we review the progress with respect to biotechnological applications of type I secretion system (T1SS) of Gram-negative bacteria. We will also focus on the applicability of T1SS for the secretion of heterologous proteins as well as vaccine development. Last but not least, we explore the employed engineering strategies that have enhanced the secretion efficiencies of T1SS. Attention is also paid to directed evolution approaches that may offer a more versatile approach to optimize secretion efficiency of T1SS.
Collapse
Affiliation(s)
- Zohreh Pourhassan N
- Institute of Biochemistry, Heinrich Heine University Düsseldorf, Universitätsstr. 1, 40225 Düsseldorf, Germany
| | - Sander H J Smits
- Institute of Biochemistry, Heinrich Heine University Düsseldorf, Universitätsstr. 1, 40225 Düsseldorf, Germany
| | - Jung Hoon Ahn
- Department of Chemistry and Biology, Korea Science Academy of Korea Advanced Institute of Science and Technology, Busan 47162, South Korea
| | - Lutz Schmitt
- Institute of Biochemistry, Heinrich Heine University Düsseldorf, Universitätsstr. 1, 40225 Düsseldorf, Germany.
| |
Collapse
|
8
|
Spengler C, Nolle F, Thewes N, Wieland B, Jung P, Bischoff M, Jacobs K. Using Knock-Out Mutants to Investigate the Adhesion of Staphylococcus aureus to Abiotic Surfaces. Int J Mol Sci 2021; 22:11952. [PMID: 34769382 PMCID: PMC8584566 DOI: 10.3390/ijms222111952] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/02/2021] [Revised: 10/29/2021] [Accepted: 10/30/2021] [Indexed: 12/19/2022] Open
Abstract
The adhesion of Staphylococcus aureus to abiotic surfaces is crucial for establishing device-related infections. With a high number of single-cell force spectroscopy measurements with genetically modified S. aureus cells, this study provides insights into the adhesion process of the pathogen to abiotic surfaces of different wettability. Our results show that S. aureus utilizes different cell wall molecules and interaction mechanisms when binding to hydrophobic and hydrophilic surfaces. We found that covalently bound cell wall proteins strongly interact with hydrophobic substrates, while their contribution to the overall adhesion force is smaller on hydrophilic substrates. Teichoic acids promote adhesion to hydrophobic surfaces as well as to hydrophilic surfaces. This, however, is to a lesser extent. An interplay of electrostatic effects of charges and protein composition on bacterial surfaces is predominant on hydrophilic surfaces, while it is overshadowed on hydrophobic surfaces by the influence of the high number of binding proteins. Our results can help to design new models of bacterial adhesion and may be used to interpret the adhesion of other microorganisms with similar surface properties.
Collapse
Affiliation(s)
- Christian Spengler
- Experimental Physics and Center for Biophysics, Saarland University, 66123 Saarbrücken, Germany; (C.S.); (F.N.); (N.T.)
| | - Friederike Nolle
- Experimental Physics and Center for Biophysics, Saarland University, 66123 Saarbrücken, Germany; (C.S.); (F.N.); (N.T.)
| | - Nicolas Thewes
- Experimental Physics and Center for Biophysics, Saarland University, 66123 Saarbrücken, Germany; (C.S.); (F.N.); (N.T.)
| | - Ben Wieland
- Institute of Medical Microbiology and Hygiene and Center for Biophysics, Saarland University, 66421 Homburg, Germany; (B.W.); (P.J.); (M.B.)
| | - Philipp Jung
- Institute of Medical Microbiology and Hygiene and Center for Biophysics, Saarland University, 66421 Homburg, Germany; (B.W.); (P.J.); (M.B.)
| | - Markus Bischoff
- Institute of Medical Microbiology and Hygiene and Center for Biophysics, Saarland University, 66421 Homburg, Germany; (B.W.); (P.J.); (M.B.)
| | - Karin Jacobs
- Experimental Physics and Center for Biophysics, Saarland University, 66123 Saarbrücken, Germany; (C.S.); (F.N.); (N.T.)
- Max Planck School Matter to Life, Jahnstraße 29, 69120 Heidelberg, Germany
| |
Collapse
|
9
|
The cell envelope of Staphylococcus aureus selectively controls the sorting of virulence factors. Nat Commun 2021; 12:6193. [PMID: 34702812 PMCID: PMC8548510 DOI: 10.1038/s41467-021-26517-z] [Citation(s) in RCA: 14] [Impact Index Per Article: 4.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/27/2020] [Accepted: 10/05/2021] [Indexed: 11/08/2022] Open
Abstract
Staphylococcus aureus bi-component pore-forming leukocidins are secreted toxins that directly target and lyse immune cells. Intriguingly, one of the leukocidins, Leukocidin AB (LukAB), is found associated with the bacterial cell envelope in addition to secreted into the extracellular milieu. Here, we report that retention of LukAB on the bacterial cells provides S. aureus with a pre-synthesized active toxin that kills immune cells. On the bacteria, LukAB is distributed as discrete foci in two distinct compartments: membrane-proximal and surface-exposed. Through genetic screens, we show that a membrane lipid, lysyl-phosphatidylglycerol (LPG), and lipoteichoic acid (LTA) contribute to LukAB deposition and release. Furthermore, by studying non-covalently surface-bound proteins we discovered that the sorting of additional exoproteins, such as IsaB, Hel, ScaH, and Geh, are also controlled by LPG and LTA. Collectively, our study reveals a multistep secretion system that controls exoprotein storage and protein translocation across the S. aureus cell wall.
Collapse
|
10
|
Halladin DK, Ortega FE, Ng KM, Footer MJ, Mitić NS, Malkov SN, Gopinathan A, Huang KC, Theriot JA. Entropy-driven translocation of disordered proteins through the Gram-positive bacterial cell wall. Nat Microbiol 2021; 6:1055-1065. [PMID: 34326523 DOI: 10.1038/s41564-021-00942-8] [Citation(s) in RCA: 6] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/17/2020] [Accepted: 06/28/2021] [Indexed: 02/07/2023]
Abstract
In Gram-positive bacteria, a thick cross-linked cell wall separates the membrane from the extracellular space. Some surface-exposed proteins, such as the Listeria monocytogenes actin nucleation-promoting factor ActA, remain associated with the bacterial membrane but somehow thread through tens of nanometres of cell wall to expose their amino terminus to the exterior. Here, we report that entropy enables the translocation of disordered transmembrane proteins through the Gram-positive cell wall. We build a physical model, which predicts that the entropic constraint imposed by a thin periplasm is sufficient to drive the translocation of an intrinsically disordered protein such as ActA across a porous barrier similar to a peptidoglycan cell wall. We experimentally validate our model and show that ActA translocation depends on the cell-envelope dimensions and disordered-protein length, and that translocation is reversible. We also show that disordered regions of eukaryotic proteins can translocate Gram-positive cell walls via entropy. We propose that entropic forces are sufficient to drive the translocation of specific proteins to the outer surface.
Collapse
Affiliation(s)
- David K Halladin
- Department of Microbiology and Immunology, Stanford University School of Medicine, Stanford, CA, USA.,Department of Biochemistry and Howard Hughes Medical Institute, Stanford University School of Medicine, Stanford, CA, USA
| | - Fabian E Ortega
- Department of Biochemistry and Howard Hughes Medical Institute, Stanford University School of Medicine, Stanford, CA, USA
| | - Katharine M Ng
- Department of Microbiology and Immunology, Stanford University School of Medicine, Stanford, CA, USA.,Department of Bioengineering, Stanford University, Stanford, CA, USA
| | - Matthew J Footer
- Department of Biochemistry and Howard Hughes Medical Institute, Stanford University School of Medicine, Stanford, CA, USA.,Department of Biology and Howard Hughes Medical Institute, University of Washington, Seattle, WA, USA
| | - Nenad S Mitić
- Faculty of Mathematics, University of Belgrade, Belgrade, Serbia
| | - Saša N Malkov
- Faculty of Mathematics, University of Belgrade, Belgrade, Serbia
| | - Ajay Gopinathan
- Department of Physics, University of California, Merced, CA, USA
| | - Kerwyn Casey Huang
- Department of Microbiology and Immunology, Stanford University School of Medicine, Stanford, CA, USA. .,Department of Bioengineering, Stanford University, Stanford, CA, USA. .,Chan Zuckerberg Biohub, San Francisco, CA, USA.
| | - Julie A Theriot
- Department of Microbiology and Immunology, Stanford University School of Medicine, Stanford, CA, USA. .,Department of Biochemistry and Howard Hughes Medical Institute, Stanford University School of Medicine, Stanford, CA, USA. .,Department of Biology and Howard Hughes Medical Institute, University of Washington, Seattle, WA, USA.
| |
Collapse
|
11
|
Recombinant protein secretion by Bacillus subtilis and Lactococcus lactis: pathways, applications, and innovation potential. Essays Biochem 2021; 65:187-195. [PMID: 33955475 PMCID: PMC8314018 DOI: 10.1042/ebc20200171] [Citation(s) in RCA: 24] [Impact Index Per Article: 8.0] [Reference Citation Analysis] [Abstract] [Key Words] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/12/2021] [Revised: 04/15/2021] [Accepted: 04/16/2021] [Indexed: 01/01/2023]
Abstract
Secreted recombinant proteins are of great significance for industry, healthcare and a sustainable bio-based economy. Consequently, there is an ever-increasing need for efficient production platforms to deliver such proteins in high amounts and high quality. Gram-positive bacteria, particularly bacilli such as Bacillus subtilis, are favored for the production of secreted industrial enzymes. Nevertheless, recombinant protein production in the B. subtilis cell factory can be very challenging due to bottlenecks in the general (Sec) secretion pathway as well as this bacterium’s intrinsic capability to secrete a cocktail of highly potent proteases. This has placed another Gram-positive bacterium, Lactococcus lactis, in the focus of attention as an alternative, non-proteolytic, cell factory for secreted proteins. Here we review our current understanding of the secretion pathways exploited in B. subtilis and L. lactis to deliver proteins from their site of synthesis, the cytoplasm, into the fermentation broth. An advantage of this cell factory comparison is that it identifies opportunities for protein secretion pathway engineering to remove or bypass current production bottlenecks. Noteworthy new developments in cell factory engineering are the mini-Bacillus concept, highlighting potential advantages of massive genome minimization, and the application of thus far untapped ‘non-classical’ protein secretion routes. Altogether, it is foreseen that engineered lactococci will find future applications in the production of high-quality proteins at the relatively small pilot scale, while engineered bacilli will remain a favored choice for protein production in bulk.
Collapse
|
12
|
McKernan P, Cassidy B, Woodward A, Battiste J, Drevets D, Harrison R. Anionic phospholipid expression as a molecular target in Listeria monocytogenes and Escherichia coli. Int J Antimicrob Agents 2020; 56:106183. [PMID: 33045345 DOI: 10.1016/j.ijantimicag.2020.106183] [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: 04/15/2020] [Revised: 07/02/2020] [Accepted: 10/04/2020] [Indexed: 10/23/2022]
Abstract
This study validates bacterial anionic phospholipids (APs) as a putative molecular target in a novel antibiotic treatment against the Gram-positive bacterium Listeria monocytogenes and the Gram-negative bacterium Escherichia coli. Bacterial AP expression was targeted with its associated protein-ligand partner, annexin A5 (ANXA5). This protein was functionalised with the covalent addition of the antibiotic ampicillin (AMP) and separately with the antibiotic moxifloxacin (MOX). Functionalised ANXA5 serves as a delivery vehicle, directing the antibiotic to bacterial AP expression. The results presented here suggest that this ANXA5-AMP bioconjugate participates in a positive feedback loop where APs, the target of the delivery vehicle ANXA5, are upregulated by the chemotherapeutic payload of the bioconjugate. Importantly, the ANXA5 delivery vehicle is non-toxic to bacterial cells by itself and neither is the ANXA5-antibiotic bioconjugate toxic to human vascular endothelial cells. As measured by the IC50, conjugation to ANXA5 resulted in increasing the antibiotic activity of AMP against L. monocytogenes and E. coli by more than 4 and 3 orders of magnitude, respectively, compared with free AMP, whilst the activity of MOX against L. monocytogenes is increased by 4 orders of magnitude. Given the conservation of AP expression in pathologies such as oncogenesis and other bacterial/viral/parasitic infections, we hypothesise that a therapeutic modality targeting AP expression may be a viable chemotherapeutic strategy in many infectious diseases.
Collapse
Affiliation(s)
- Patrick McKernan
- Department of Neurology, University of Oklahoma Health Sciences Center, 865 Research Parkway, Oklahoma City, OK 73104, USA; Department of Neurosurgery, University of Oklahoma Health Sciences Center, Oklahoma City, OK, USA; Department of Radiation Oncology, University of Oklahoma Health Sciences Center Oklahoma City, OK, USA
| | - Benjamin Cassidy
- Department of Medicine, University of Oklahoma Health Sciences Center, Oklahoma City, OK, USA
| | - Alexis Woodward
- School of Biomedical Engineering, University of Oklahoma, 202 W. Boyd St., Norman, OK 73019, USA
| | - James Battiste
- Department of Neurology, University of Oklahoma Health Sciences Center, 865 Research Parkway, Oklahoma City, OK 73104, USA; Stephenson Cancer Center, 800 NE 10th St., Oklahoma City, OK 73104, USA
| | - Douglas Drevets
- Department of Medicine, University of Oklahoma Health Sciences Center, Oklahoma City, OK, USA; Medical Services, Department of Veterans Affairs Medical Center, 921 NE 13th St., Oklahoma City, OK 73104, USA
| | - Roger Harrison
- Stephenson Cancer Center, 800 NE 10th St., Oklahoma City, OK 73104, USA; School of Chemical, Biological and Materials Engineering, University of Oklahoma, 100 E. Boyd St., Norman, OK 73019, USA.
| |
Collapse
|
13
|
Zhang Y, Yu S, Xie R, Li J, Leier A, Marquez-Lago TT, Akutsu T, Smith AI, Ge Z, Wang J, Lithgow T, Song J. PeNGaRoo, a combined gradient boosting and ensemble learning framework for predicting non-classical secreted proteins. Bioinformatics 2020; 36:704-712. [PMID: 31393553 DOI: 10.1093/bioinformatics/btz629] [Citation(s) in RCA: 21] [Impact Index Per Article: 5.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/03/2019] [Revised: 07/17/2019] [Accepted: 08/07/2019] [Indexed: 12/17/2022] Open
Abstract
MOTIVATION Gram-positive bacteria have developed secretion systems to transport proteins across their cell wall, a process that plays an important role during host infection. These secretion mechanisms have also been harnessed for therapeutic purposes in many biotechnology applications. Accordingly, the identification of features that select a protein for efficient secretion from these microorganisms has become an important task. Among all the secreted proteins, 'non-classical' secreted proteins are difficult to identify as they lack discernable signal peptide sequences and can make use of diverse secretion pathways. Currently, several computational methods have been developed to facilitate the discovery of such non-classical secreted proteins; however, the existing methods are based on either simulated or limited experimental datasets. In addition, they often employ basic features to train the models in a simple and coarse-grained manner. The availability of more experimentally validated datasets, advanced feature engineering techniques and novel machine learning approaches creates new opportunities for the development of improved predictors of 'non-classical' secreted proteins from sequence data. RESULTS In this work, we first constructed a high-quality dataset of experimentally verified 'non-classical' secreted proteins, which we then used to create benchmark datasets. Using these benchmark datasets, we comprehensively analyzed a wide range of features and assessed their individual performance. Subsequently, we developed a two-layer Light Gradient Boosting Machine (LightGBM) ensemble model that integrates several single feature-based models into an overall prediction framework. At this stage, LightGBM, a gradient boosting machine, was used as a machine learning approach and the necessary parameter optimization was performed by a particle swarm optimization strategy. All single feature-based LightGBM models were then integrated into a unified ensemble model to further improve the predictive performance. Consequently, the final ensemble model achieved a superior performance with an accuracy of 0.900, an F-value of 0.903, Matthew's correlation coefficient of 0.803 and an area under the curve value of 0.963, and outperforming previous state-of-the-art predictors on the independent test. Based on our proposed optimal ensemble model, we further developed an accessible online predictor, PeNGaRoo, to serve users' demands. We believe this online web server, together with our proposed methodology, will expedite the discovery of non-classically secreted effector proteins in Gram-positive bacteria and further inspire the development of next-generation predictors. AVAILABILITY AND IMPLEMENTATION http://pengaroo.erc.monash.edu/. SUPPLEMENTARY INFORMATION Supplementary data are available at Bioinformatics online.
Collapse
Affiliation(s)
- Yanju Zhang
- Bioinformatics Group, School of Computer Science and Information Security, Guilin University of Electronic Technology, Guilin 541004, China
| | - Sha Yu
- Bioinformatics Group, School of Computer Science and Information Security, Guilin University of Electronic Technology, Guilin 541004, China.,Infection and Immunity Program, Biomedicine Discovery Institute and Department of Biochemistry and Molecular Biology, VIC 3800, Australia
| | - Ruopeng Xie
- Bioinformatics Group, School of Computer Science and Information Security, Guilin University of Electronic Technology, Guilin 541004, China.,Infection and Immunity Program, Biomedicine Discovery Institute and Department of Biochemistry and Molecular Biology, VIC 3800, Australia
| | - Jiahui Li
- Bioinformatics Group, School of Computer Science and Information Security, Guilin University of Electronic Technology, Guilin 541004, China.,Infection and Immunity Program, Biomedicine Discovery Institute and Department of Microbiology, Monash University, Melbourne, VIC 3800, Australia
| | - André Leier
- Department of Genetics, AL, USA.,Department of Cell, Developmental and Integrative Biology, School of Medicine, University of Alabama at Birmingham, AL, USA
| | - Tatiana T Marquez-Lago
- Department of Genetics, AL, USA.,Department of Cell, Developmental and Integrative Biology, School of Medicine, University of Alabama at Birmingham, AL, USA
| | - Tatsuya Akutsu
- Bioinformatics Center, Institute for Chemical Research, Kyoto University, Uji, Kyoto 611-0011, Japan
| | - A Ian Smith
- Infection and Immunity Program, Biomedicine Discovery Institute and Department of Biochemistry and Molecular Biology, VIC 3800, Australia.,ARC Centre of Excellence in Advanced Molecular Imaging, Monash University, VIC 3800, Australia
| | - Zongyuan Ge
- Monash e-Research Centre and Faculty of Engineering, Monash University, Melbourne, VIC 3800, Australia
| | - Jiawei Wang
- Infection and Immunity Program, Biomedicine Discovery Institute and Department of Microbiology, Monash University, Melbourne, VIC 3800, Australia
| | - Trevor Lithgow
- Infection and Immunity Program, Biomedicine Discovery Institute and Department of Microbiology, Monash University, Melbourne, VIC 3800, Australia
| | - Jiangning Song
- Infection and Immunity Program, Biomedicine Discovery Institute and Department of Biochemistry and Molecular Biology, VIC 3800, Australia.,ARC Centre of Excellence in Advanced Molecular Imaging, Monash University, VIC 3800, Australia
| |
Collapse
|
14
|
Irla M, Drejer EB, Brautaset T, Hakvåg S. Establishment of a functional system for recombinant production of secreted proteins at 50 °C in the thermophilic Bacillus methanolicus. Microb Cell Fact 2020; 19:151. [PMID: 32723337 PMCID: PMC7389648 DOI: 10.1186/s12934-020-01409-x] [Citation(s) in RCA: 8] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/17/2019] [Accepted: 07/20/2020] [Indexed: 01/06/2023] Open
Abstract
BACKGROUND The suitability of bacteria as microbial cell factories is dependent on several factors such as price of feedstock, product range, production yield and ease of downstream processing. The facultative methylotroph Bacillus methanolicus is gaining interest as a thermophilic cell factory for production of value-added products from methanol. The aim of this study was to expand the capabilities of B. methanolicus as a microbial cell factory by establishing a system for secretion of recombinant proteins. RESULTS Native and heterologous signal peptides were tested for secretion of α-amylases and proteases, and we have established the use of the thermostable superfolder green fluorescent protein (sfGFP) as a valuable reporter protein in B. methanolicus. We demonstrated functional production and secretion of recombinant proteases, α-amylases and sfGFP in B. methanolicus MGA3 at 50 °C and showed that the choice of signal peptide for optimal secretion efficiency varies between proteins. In addition, we showed that heterologous production and secretion of α-amylase from Geobacillus stearothermophilus enables B. methanolicus to grow in minimal medium with starch as the sole carbon source. An in silico signal peptide library consisting of 169 predicted peptides from B. methanolicus was generated and will be useful for future studies, but was not experimentally investigated any further here. CONCLUSION A functional system for recombinant production of secreted proteins at 50 °C has been established in the thermophilic B. methanolicus. In addition, an in silico signal peptide library has been generated, that together with the tools and knowledge presented in this work will be useful for further development of B. methanolicus as a host for recombinant protein production and secretion at 50 °C.
Collapse
Affiliation(s)
- Marta Irla
- Department of Biotechnology and Food Sciences, Norwegian University of Science and Technology (NTNU), Trondheim, Norway
| | - Eivind B Drejer
- Department of Biotechnology and Food Sciences, Norwegian University of Science and Technology (NTNU), Trondheim, Norway
| | - Trygve Brautaset
- Department of Biotechnology and Food Sciences, Norwegian University of Science and Technology (NTNU), Trondheim, Norway
| | - Sigrid Hakvåg
- Department of Biotechnology and Food Sciences, Norwegian University of Science and Technology (NTNU), Trondheim, Norway.
| |
Collapse
|
15
|
Overview of Staphylococcus epidermidis cell wall-anchored proteins: potential targets to inhibit biofilm formation. Mol Biol Rep 2019; 47:771-784. [DOI: 10.1007/s11033-019-05139-1] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/16/2019] [Accepted: 10/11/2019] [Indexed: 12/18/2022]
|
16
|
Zhao C, Wang X, Wu L, Wu W, Zheng Y, Lin L, Weng S, Lin X. Nitrogen-doped carbon quantum dots as an antimicrobial agent against Staphylococcus for the treatment of infected wounds. Colloids Surf B Biointerfaces 2019; 179:17-27. [PMID: 30928801 DOI: 10.1016/j.colsurfb.2019.03.042] [Citation(s) in RCA: 49] [Impact Index Per Article: 9.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/04/2018] [Revised: 02/21/2019] [Accepted: 03/18/2019] [Indexed: 02/07/2023]
Abstract
Antimicrobial resistance is becoming more and more serious and has become a potential hazard to human life and health. The fabrication of some new antibacterial substances against resistant bacteria is demanded. With the wide application and research of carbon nanomaterials, nitrogen-doped carbon quantum dots (NCQDs) were synthesized by a one-step chemical route herein. The particle size of NCQDs in the range of 2-5 nm were characterized by transmission electron microscopy (TEM), atomic force microscopy, and dynamic light scattering. The functional groups and optical properties of NCQDs were investigated by UV-vis absorption spectroscopy, X-ray photoelectron spectroscopy and Fourier transform infrared spectroscopy. Disk-diffusion tests showed that the NCQDs had specific antibacterial activity against Staphylococcus. TEM showed that the NCQDs could destroy the cell structure of Staphylococcus aureus and methicillin-resistant Staphylococcus aureus (MRSA) but could not combat Escherichia coli. The antibacterial mechanism may be that positively charged NCQDs firstly interacted with the negatively charged bacteria, and then specifically anchored on some specific sites on the surface of Staphylococcus. The NCQDs were applied to treat wounds infected with MRSA and showed the same therapeutic effect as vancomycin. Photomicrographs of hematoxylin-eosin-stained histological sections showed that the NCQDs at concentrations effectively killing S. aureus and MRSA caused negligible toxicity to the main rat organs, including heart, liver, spleen, lung, and kidney. Thus, the NCQDs can be developed as a promising antibacterial agent for Staphylococcus. And the NCQDs are likely to treat local infections caused by Staphylococcus clinically, especially S. aureus and MRSA.
Collapse
Affiliation(s)
- Chengfei Zhao
- Department of Pharmaceutical Analysis, School of Pharmacy, Fujian Medical University, Fuzhou 350122, China
| | - Xuewen Wang
- Department of Pharmaceutical Analysis, School of Pharmacy, Fujian Medical University, Fuzhou 350122, China
| | - Lina Wu
- Department of Pharmaceutical Analysis, School of Pharmacy, Fujian Medical University, Fuzhou 350122, China
| | - Wen Wu
- Department of Orthopedic Surgery, Fujian Medical University Union Hospital, Fuzhou 350001, China
| | - Yanjie Zheng
- Department of Pharmaceutical Analysis, School of Pharmacy, Fujian Medical University, Fuzhou 350122, China; The Higher Educational Key Laboratory for Nano Biomedical Technology of Fujian Province, Fujian Medical University, Fuzhou 350004, China
| | - Liqing Lin
- Department of Pharmaceutical Analysis, School of Pharmacy, Fujian Medical University, Fuzhou 350122, China; The Higher Educational Key Laboratory for Nano Biomedical Technology of Fujian Province, Fujian Medical University, Fuzhou 350004, China
| | - Shaohuang Weng
- Department of Pharmaceutical Analysis, School of Pharmacy, Fujian Medical University, Fuzhou 350122, China; The Higher Educational Key Laboratory for Nano Biomedical Technology of Fujian Province, Fujian Medical University, Fuzhou 350004, China.
| | - Xinhua Lin
- Department of Pharmaceutical Analysis, School of Pharmacy, Fujian Medical University, Fuzhou 350122, China; The Higher Educational Key Laboratory for Nano Biomedical Technology of Fujian Province, Fujian Medical University, Fuzhou 350004, China.
| |
Collapse
|
17
|
Thermostable Xylanase Production by Geobacillus sp. Strain DUSELR13, and Its Application in Ethanol Production with Lignocellulosic Biomass. Microorganisms 2018; 6:microorganisms6030093. [PMID: 30189618 PMCID: PMC6164562 DOI: 10.3390/microorganisms6030093] [Citation(s) in RCA: 36] [Impact Index Per Article: 6.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/05/2018] [Revised: 08/29/2018] [Accepted: 08/31/2018] [Indexed: 01/11/2023] Open
Abstract
The aim of the current study was to optimize the production of xylanase, and its application for ethanol production using the lignocellulosic biomass. A highly thermostable crude xylanase was obtained from the Geobacillus sp. strain DUSELR13 isolated from the deep biosphere of Homestake gold mine, Lead, SD. Geobacillus sp. strain DUSELR13 produced 6 U/mL of the xylanase with the beechwood xylan. The xylanase production was improved following the optimization studies, with one factor at a time approach, from 6 U/mL to 19.8 U/mL with xylan. The statistical optimization with response surface methodology further increased the production to 31 U/mL. The characterization studies revealed that the crude xylanase complex had an optimum pH of 7.0, with a broad pH range of 5.0⁻9.0, and an optimum temperature of 75 °C. The ~45 kDa xylanase protein was highly thermostable with t1/2 of 48, 38, and 13 days at 50, 60, and 70 °C, respectively. The xylanase activity increased with the addition of Cu+2, Zn+2, K+, and Fe+2 at 1 mM concentration, and Ca+2, Zn+2, Mg+2, and Na⁺ at 10 mM concentration. The comparative analysis of the crude xylanase against its commercial counterpart Novozymes Cellic HTec and Dupont, Accellerase XY, showed that it performed better at higher temperature, hydrolyzing 65.4% of the beechwood at 75 °C. The DUSEL R13 showed the mettle to hydrolyze, and utilize the pretreated, and untreated lignocellulosic biomass: prairie cord grass (PCG), and corn stover (CS) as the substrate, and gave a maximum yield of 20.5 U/mL with the untreated PCG. When grown in co-culture with Geobacillus thermoglucosidasius, it produced 3.53 and 3.72 g/L ethanol, respectively with PCG, and CS. With these characteristics the xylanase under study could be an industrial success for the high temperature bioprocesses.
Collapse
|
18
|
Desvaux M, Candela T, Serror P. Surfaceome and Proteosurfaceome in Parietal Monoderm Bacteria: Focus on Protein Cell-Surface Display. Front Microbiol 2018; 9:100. [PMID: 29491848 PMCID: PMC5817068 DOI: 10.3389/fmicb.2018.00100] [Citation(s) in RCA: 24] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/29/2017] [Accepted: 01/16/2018] [Indexed: 12/12/2022] Open
Abstract
The cell envelope of parietal monoderm bacteria (archetypal Gram-positive bacteria) is formed of a cytoplasmic membrane (CM) and a cell wall (CW). While the CM is composed of phospholipids, the CW is composed at least of peptidoglycan (PG) covalently linked to other biopolymers, such as teichoic acids, polysaccharides, and/or polyglutamate. Considering the CW is a porous structure with low selective permeability contrary to the CM, the bacterial cell surface hugs the molecular figure of the CW components as a well of the external side of the CM. While the surfaceome corresponds to the totality of the molecules found at the bacterial cell surface, the proteinaceous complement of the surfaceome is the proteosurfaceome. Once translocated across the CM, secreted proteins can either be released in the extracellular milieu or exposed at the cell surface by associating to the CM or the CW. Following the gene ontology (GO) for cellular components, cell-surface proteins at the CM can either be integral (GO: 0031226), i.e., the integral membrane proteins, or anchored to the membrane (GO: 0046658), i.e., the lipoproteins. At the CW (GO: 0009275), cell-surface proteins can be covalently bound, i.e., the LPXTG-proteins, or bound through weak interactions to the PG or wall polysaccharides, i.e., the cell wall binding proteins. Besides monopolypeptides, some proteins can associate to each other to form supramolecular protein structures of high molecular weight, namely the S-layer, pili, flagella, and cellulosomes. After reviewing the cell envelope components and the different molecular mechanisms involved in protein attachment to the cell envelope, perspectives in investigating the proteosurfaceome in parietal monoderm bacteria are further discussed.
Collapse
Affiliation(s)
- Mickaël Desvaux
- Université Clermont Auvergne, INRA, UMR454 MEDiS, Clermont-Ferrand, France
| | - Thomas Candela
- EA4043 Unité Bactéries Pathogènes et Santé, Châtenay-Malabry, France
| | - Pascale Serror
- Micalis Institute, INRA, AgroParisTech, Université Paris-Saclay, Jouy-en-Josas, France
| |
Collapse
|
19
|
Protein Secretion in Gram-Positive Bacteria: From Multiple Pathways to Biotechnology. Curr Top Microbiol Immunol 2017; 404:267-308. [PMID: 27885530 DOI: 10.1007/82_2016_49] [Citation(s) in RCA: 27] [Impact Index Per Article: 3.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/08/2023]
Abstract
A number of Gram-positive bacteria are important players in industry as producers of a diverse array of economically interesting metabolites and proteins. As discussed in this overview, several Gram-positive bacteria are valuable hosts for the production of heterologous proteins. In contrast to Gram-negative bacteria, proteins secreted by Gram-positive bacteria are released into the culture medium where conditions for correct folding are more appropriate, thus facilitating the isolation and purification of active proteins. Although seven different protein secretion pathways have been identified in Gram-positive bacteria, the majority of heterologous proteins are produced via the general secretion or Sec pathway. Not all proteins are equally well secreted, because heterologous protein production often faces bottlenecks including hampered secretion, susceptibility to proteases, secretion stress, and metabolic burden. These bottlenecks are associated with reduced yields leading to non-marketable products. In this chapter, besides a general overview of the different protein secretion pathways, possible hurdles that may hinder efficient protein secretion are described and attempts to improve yield are discussed including modification of components of the Sec pathway. Attention is also paid to omics-based approaches that may offer a more rational approach to optimize production of heterologous proteins.
Collapse
|
20
|
Yan S, Wu G. Bottleneck in secretion of α-amylase in Bacillus subtilis. Microb Cell Fact 2017; 16:124. [PMID: 28724440 PMCID: PMC5518135 DOI: 10.1186/s12934-017-0738-1] [Citation(s) in RCA: 24] [Impact Index Per Article: 3.4] [Reference Citation Analysis] [Abstract] [Key Words] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/27/2017] [Accepted: 07/10/2017] [Indexed: 11/10/2022] Open
Abstract
Amylase plays an important role in biotechnology industries, and Gram-positive bacterium Bacillus subtilis is a major host to produce heterogeneous α-amylases. However, the secretion stress limits the high yield of α-amylase in B. subtilis although huge efforts have been made to address this secretion bottleneck. In this question-oriented review, every effort is made to answer the following questions, which look simple but are long-standing, through reviewing of literature: (1) Does α-amylase need a specific and dedicated chaperone? (2) What signal sequence does CsaA recognize? (3) Does CsaA require ATP for its operation? (4) Does an unfolded α-amylase is less soluble than a folded one? (5) Does α-amylase aggregate before transporting through Sec secretion system? (6) Is α-amylase sufficient stable to prevent itself from misfolding? (7) Does α-amylase need more disulfide bonds to be stabilized? (8) Which secretion system does PrsA pass through? (9) Is PrsA ATP-dependent? (10) Is PrsA reused after folding of α-amylase? (11) What is the fate of PrsA? (12) Is trigger factor (TF) ATP-dependent? The literature review suggests that not only the most of those questions are still open to answers but also it is necessary to calculate ATP budget in order to better understand how B. subtilis uses its energy for production and secretion.
Collapse
Affiliation(s)
- Shaomin Yan
- National Engineering Research Center for Non-food Biorefinery, Guangxi Academy of Sciences, 98 Daling Road, Nanning, 530007, Guangxi, China
| | - Guang Wu
- National Engineering Research Center for Non-food Biorefinery, Guangxi Academy of Sciences, 98 Daling Road, Nanning, 530007, Guangxi, China.
| |
Collapse
|
21
|
Whitney JC, Peterson SB, Kim J, Pazos M, Verster AJ, Radey MC, Kulasekara HD, Ching MQ, Bullen NP, Bryant D, Goo YA, Surette MG, Borenstein E, Vollmer W, Mougous JD. A broadly distributed toxin family mediates contact-dependent antagonism between gram-positive bacteria. eLife 2017; 6. [PMID: 28696203 PMCID: PMC5555719 DOI: 10.7554/elife.26938] [Citation(s) in RCA: 99] [Impact Index Per Article: 14.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/20/2017] [Accepted: 07/10/2017] [Indexed: 12/24/2022] Open
Abstract
The Firmicutes are a phylum of bacteria that dominate numerous polymicrobial habitats of importance to human health and industry. Although these communities are often densely colonized, a broadly distributed contact-dependent mechanism of interbacterial antagonism utilized by Firmicutes has not been elucidated. Here we show that proteins belonging to the LXG polymorphic toxin family present in Streptococcus intermedius mediate cell contact- and Esx secretion pathway-dependent growth inhibition of diverse Firmicute species. The structure of one such toxin revealed a previously unobserved protein fold that we demonstrate directs the degradation of a uniquely bacterial molecule required for cell wall biosynthesis, lipid II. Consistent with our functional data linking LXG toxins to interbacterial interactions in S. intermedius, we show that LXG genes are prevalent in the human gut microbiome, a polymicrobial community dominated by Firmicutes. We speculate that interbacterial antagonism mediated by LXG toxins plays a critical role in shaping Firmicute-rich bacterial communities. DOI:http://dx.doi.org/10.7554/eLife.26938.001 Most bacteria live in densely colonized environments, such as the human gut, in which they must constantly compete with other microbes for space and nutrients. As a result, bacteria have evolved a wide array of strategies to directly fight their neighbors. For example, some bacteria release antimicrobial compounds into their surroundings, while others ‘inject’ protein toxins directly into adjacent cells. Bacteria can be classified into two groups known as Gram-positive and Gram-negative. Previous studies found that Gram-negative bacteria inject toxins into neighboring cells, but no comparable toxins in Gram-positive bacteria had been identified. Before a bacterium can inject molecules into an adjacent cell, it needs to move the toxins from its interior to the cell surface. It had been suggested that a transport system in Gram-positive bacteria called the Esx pathway may export toxins known as LXG proteins. However, it was not clear whether these proteins help Gram-positive bacteria to compete against other bacteria. Whitney et al. studied the LXG proteins in Gram-positive bacteria known as Firmicutes. The experiments reveal that Firmicutes found in the human gut possess LXG genes. A Firmicute known as Streptococcus intermedius produces three LXG proteins that are all toxic to bacteria. To avoid being harmed by its own LXG proteins, S. intermedius also produces matching antidote proteins. Further experiments show that LXG proteins are exported out of S. intermedius cells and into adjacent competitor bacteria by the Esx pathway. Examining one of these LXG proteins in more detail showed that it can degrade a molecule that bacteria need to make their cell wall. Together, these findings suggest that LXG proteins may influence the species living in many important microbial communities, including the human gut. Changes in the communities of gut microbes have been linked with many diseases. Therefore, understanding more about how the LXG proteins work may help us to develop ways to manipulate these communities to improve human health. DOI:http://dx.doi.org/10.7554/eLife.26938.002
Collapse
Affiliation(s)
- John C Whitney
- Department of Microbiology, University of Washington School of Medicine, Seattle, United States
| | - S Brook Peterson
- Department of Microbiology, University of Washington School of Medicine, Seattle, United States
| | - Jungyun Kim
- Department of Microbiology, University of Washington School of Medicine, Seattle, United States
| | - Manuel Pazos
- Centre for Bacterial Cell Biology, Institute for Cell and Molecular Biosciences, Newcastle University, Newcastle, United Kingdom
| | - Adrian J Verster
- Department of Genome Sciences, University of Washington, Seattle, United States
| | - Matthew C Radey
- Department of Microbiology, University of Washington School of Medicine, Seattle, United States
| | - Hemantha D Kulasekara
- Department of Microbiology, University of Washington School of Medicine, Seattle, United States
| | - Mary Q Ching
- Department of Microbiology, University of Washington School of Medicine, Seattle, United States
| | - Nathan P Bullen
- Michael DeGroote Institute for Infectious Disease Research, McMaster University, Hamilton, Canada.,Department of Biochemistry and Biomedical Sciences, McMaster University, Hamilton, Canada
| | - Diane Bryant
- Experimental Systems Group, Advanced Light Source, Berkeley, United States
| | - Young Ah Goo
- Northwestern Proteomics Core Facility, Northwestern University, Chicago, United States
| | - Michael G Surette
- Michael DeGroote Institute for Infectious Disease Research, McMaster University, Hamilton, Canada.,Department of Biochemistry and Biomedical Sciences, McMaster University, Hamilton, Canada.,Department of Medicine, Farncombe Family Digestive Health Research Institute, McMaster University, Hamilton, Canada
| | - Elhanan Borenstein
- Department of Genome Sciences, University of Washington, Seattle, United States.,Department of Computer Science and Engineering, University of Washington, Seattle, United States.,Santa Fe Institute, Santa Fe, United States
| | - Waldemar Vollmer
- Centre for Bacterial Cell Biology, Institute for Cell and Molecular Biosciences, Newcastle University, Newcastle, United Kingdom
| | - Joseph D Mougous
- Department of Microbiology, University of Washington School of Medicine, Seattle, United States.,Howard Hughes Medical Institute, University of Washington School of Medicine, Seattle, United States
| |
Collapse
|
22
|
Cahoon LA, Freitag NE, Prehna G. A structural comparison of Listeria monocytogenes protein chaperones PrsA1 and PrsA2 reveals molecular features required for virulence. Mol Microbiol 2016; 101:42-61. [PMID: 27007641 PMCID: PMC4925323 DOI: 10.1111/mmi.13367] [Citation(s) in RCA: 12] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Accepted: 02/29/2016] [Indexed: 12/26/2022]
Abstract
Listeria monocytogenes is a Gram-positive environmental bacterium that lives within soil but transitions into a pathogen upon contact with a mammalian host. The transition of L. monocytogenes from soil dweller to cytosolic pathogen is dependent upon secreted virulence factors that mediate cell invasion and intracellular growth. PrsA1 and PrsA2 are secreted bacterial lipoprotein chaperones that contribute to the folding of proteins translocated across the bacterial membrane; PrsA2 is required for L. monocytogenes virulence, whereas the function of PrsA1 remains to be determined. We have solved an X-ray crystal structure of PrsA1 and have used this model to guide comparison structure-based mutagenesis studies with PrsA2. Targeted mutagenesis of PrsA2 demonstrates that oligomerization of PrsA2 as well as molecular features of the foldase domain are required for protein secretion and virulence, whereas a functional role was uncovered for PrsA1 in bacterial resistance to alcohol. Interestingly, PrsA2 membrane localization is not required for all PrsA2-dependent activities, suggesting that the lipoprotein retains function when released from the bacterial cell. PrsA chaperones are thus multifaceted proteins with distinct domains adapted to accommodate the functional needs of a diverse array of secreted substrates.
Collapse
Affiliation(s)
- Laty A. Cahoon
- Department of Microbiology and Immunology, University of Illinois at Chicago
| | - Nancy E. Freitag
- Department of Microbiology and Immunology, University of Illinois at Chicago
| | - Gerd Prehna
- Department of Microbiology and Immunology, University of Illinois at Chicago
- Center for Structural Biology Research Resources Center, University of Illinois at Chicago
| |
Collapse
|
23
|
The Metalloprotease Mpl Supports Listeria monocytogenes Dissemination through Resolution of Membrane Protrusions into Vacuoles. Infect Immun 2016; 84:1806-1814. [PMID: 27068088 DOI: 10.1128/iai.00130-16] [Citation(s) in RCA: 14] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/12/2016] [Accepted: 04/01/2016] [Indexed: 11/20/2022] Open
Abstract
Listeria monocytogenes is an intracellular pathogen that disseminates within the intestinal epithelium through acquisition of actin-based motility and formation of plasma membrane protrusions that project into adjacent cells. The resolution of membrane protrusions into vacuoles from which the pathogen escapes results in bacterial spread from cell to cell. This dissemination process relies on the mlp-actA-plcB operon, which encodes ActA, a bacterial nucleation-promoting factor that mediates actin-based motility, and PlcB, a phospholipase that mediates vacuole escape. Here we investigated the role of the metalloprotease Mpl in the dissemination process. In agreement with previous findings showing that Mpl is required for PlcB activation, infection of epithelial cells with the ΔplcB or Δmpl strains resulted in the formation of small infection foci. As expected, the ΔplcB strain displayed a strong defect in vacuole escape. However, the Δmpl strain showed an unexpected defect in the resolution of protrusions into vacuoles, in addition to the expected but mild defect in vacuole escape. The Δmpl strain displayed increased levels of ActA on the bacterial surface in protrusions. We mapped an Mpl-dependent processing site in ActA between amino acid residues 207 to 238. Similar to the Δmpl strain, the ΔactA207-238 strain displayed increased levels of ActA on the bacterial surface in protrusions. Although the ΔactA207-238 strain displayed wild-type actin-based motility, it formed small infection foci and failed to resolve protrusions into vacuoles. We propose that, in addition to its role in PlcB processing and vacuole escape, the metalloprotease Mpl is required for ActA processing and protrusion resolution.
Collapse
|
24
|
A new strategy to express the extracellular α-amylase from Pyrococcus furiosus in Bacillus amyloliquefaciens. Sci Rep 2016; 6:22229. [PMID: 26916714 PMCID: PMC4768087 DOI: 10.1038/srep22229] [Citation(s) in RCA: 24] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/02/2015] [Accepted: 02/05/2016] [Indexed: 11/12/2022] Open
Abstract
Extracellular α-amylase from Pyrococcus furiosus (PFA) shows great starch-processing potential for industrial application due to its thermostability, long half-life and optimal activity at low pH; however, it is difficult to produce in large quantities. In contrast, α-amylase from Bacillus amyloliquefaciens (BAA) can be produced in larger quantities, but shows lower stability at high temperatures and low pH. Here, we describe a BAA protein expression pattern-mimicking strategy to express PFA in B. amyloliquefaciens using the expression and secretion elements of BAA, including the codon usage bias and mRNA structure of gene, promoter, signal peptide, host and cultivation conditions. This design was assessed to be successful by comparing the various genes (mpfa and opfa), promoters (PamyA and P43), and strains (F30, F31, F32 and F30-∆amyA). The final production of PFA yielded 2714 U/mL, about 3000- and 14-fold that reportedly produced in B. subtilis or E. coli, respectively. The recombinant PFA was optimally active at ~100 °C and pH 5 and did not require Ca2+ for activity or thermostability, and >80% of the enzyme activity was retained after treatment at 100 °C for 4 h.
Collapse
|
25
|
Crowley PJ, Brady LJ. Evaluation of the effects of Streptococcus mutans chaperones and protein secretion machinery components on cell surface protein biogenesis, competence, and mutacin production. Mol Oral Microbiol 2015; 31:59-77. [PMID: 26386361 DOI: 10.1111/omi.12130] [Citation(s) in RCA: 10] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Accepted: 08/26/2015] [Indexed: 11/29/2022]
Abstract
The respective contributions of components of the protein translocation/maturation machinery to cell surface biogenesis in Streptococcus mutans are not fully understood. Here we used a genetic approach to characterize the effects of deletion of genes encoding the ribosome-associated chaperone RopA (Trigger Factor), the surface-localized foldase PrsA, and the membrane-localized chaperone insertases YidC1 and YidC2, both singly and in combination, on bacterial growth, chain length, self-aggregation, cell surface hydrophobicity, autolysis, and antigenicity of surface proteins P1 (AgI/II, PAc), WapA, GbpC, and GtfD. The single and double deletion mutants, as well as additional mutant strains lacking components of the signal recognition particle pathway, were also evaluated for their effects on mutacin production and genetic competence.
Collapse
Affiliation(s)
- P J Crowley
- Department of Oral Biology, College of Dentistry, University of Florida, Gainesville, FL, USA
| | - L J Brady
- Department of Oral Biology, College of Dentistry, University of Florida, Gainesville, FL, USA
| |
Collapse
|
26
|
Identification of Conserved and Species-Specific Functions of the Listeria monocytogenes PrsA2 Secretion Chaperone. Infect Immun 2015. [PMID: 26216425 DOI: 10.1128/iai.00504-15] [Citation(s) in RCA: 13] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/27/2022] Open
Abstract
The Gram-positive bacterium Listeria monocytogenes is a facultative intracellular pathogen that relies on the regulated secretion and activity of a variety of proteins that sustain life within diverse environments. PrsA2 has recently been identified as a secreted peptidyl-prolyl cis/trans isomerase and chaperone that is dispensable for bacterial growth in broth culture but essential for L. monocytogenes virulence. Following host infection, PrsA2 contributes to the proper folding and activity of secreted proteins that are required for bacterial replication within the host cytosol and for bacterial spread to adjacent cells. PrsA2 is one member of a family of Gram-positive secretion chaperones that appear to play important roles in bacterial physiology; however, it is not known how these proteins recognize their substrate proteins or the degree to which their function is conserved across diverse Gram-positive species. We therefore examined PrsA proteins encoded by a variety of Gram-positive bacteria for functional complementation of L. monocytogenes mutants lacking prsA2. PrsA homologues encoded by Bacillus subtilis, Streptococcus pyogenes, Streptococcus pneumoniae, Streptococcus mutans, Staphylococcus aureus, and Lactococcus lactis were examined for functional complementation of a variety of L. monocytogenes PrsA2-associated phenotypes central to L. monocytogenes pathogenesis and bacterial cell physiology. Our results indicate that while selected aspects of PrsA2 function are broadly conserved among diverse Gram-positive bacteria, PrsA2 exhibits unique specificity for L. monocytogenes target proteins required for pathogenesis. The L. monocytogenes PrsA2 chaperone thus appears evolutionarily optimized for virulence factor secretion within the host cell cytosol while still maintaining aspects of activity relevant to more general features of Gram-positive protein translocation.
Collapse
|
27
|
Morrison JM, John GH. Non-classical azoreductase secretion in Clostridium perfringens in response to sulfonated azo dye exposure. Anaerobe 2015; 34:34-43. [PMID: 25881497 DOI: 10.1016/j.anaerobe.2015.04.007] [Citation(s) in RCA: 14] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/23/2015] [Revised: 03/27/2015] [Accepted: 04/12/2015] [Indexed: 01/06/2023]
Abstract
Clostridium perfringens, a strictly anaerobic microorganism and inhabitant of the human intestine, has been shown to produce an azoreductase enzyme (AzoC), an NADH-dependent flavin oxidoreductase. This enzyme reduces azo dyes into aromatic amines, which can be carcinogenic. A significant amount of work has been completed on the activity of AzoC. Despite this, much is still unknown, including whether azoreduction of these dyes occurs intracellularly or extracellulary. A physiological study of C. perfringens involving the effect of azo dye exposure was completed to answer this question. Through exposure studies, azo dyes were found to cause cytoplasmic protein release, including AzoC, from C. perfringens in dividing and non-dividing cells. Sulfonation (negative charge) of azo dyes proved to be the key to facilitating protein release of AzoC and was found to be azo-dye-concentration-dependent. Additionally, AzoC was found to localize to the Gram-positive periplasmic region. Using a ΔazoC knockout mutant, the presence of additional azoreductases in C. perfringens was suggested. These results support the notion that the azoreduction of these dyes may occur extracellularly for the commensal C. perfringens in the intestine.
Collapse
Affiliation(s)
- Jessica M Morrison
- Oklahoma State University, Department of Microbiology and Molecular Genetics, 307 Life Science East, Stillwater, OK 74078, USA.
| | - Gilbert H John
- Oklahoma State University, Department of Microbiology and Molecular Genetics, 307 Life Science East, Stillwater, OK 74078, USA
| |
Collapse
|
28
|
Ruer S, Pinotsis N, Steadman D, Waksman G, Remaut H. Virulence-targeted Antibacterials: Concept, Promise, and Susceptibility to Resistance Mechanisms. Chem Biol Drug Des 2015; 86:379-99. [DOI: 10.1111/cbdd.12517] [Citation(s) in RCA: 59] [Impact Index Per Article: 6.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/28/2014] [Revised: 12/23/2014] [Accepted: 01/06/2015] [Indexed: 12/25/2022]
Affiliation(s)
- Ségolène Ruer
- Structural and Molecular Microbiology; Structural Biology Research Center; VIB; Pleinlaan 2 Brussels 1050 Belgium
- Structural Biology Brussels; Vrije Universiteit Brussel; Pleinlaan 2 Brussels 1050 Belgium
| | - Nikos Pinotsis
- Institute of Structural and Molecular Biology (ISMB); UCL and Birkbeck College; London WC1E 7HX UK
| | - David Steadman
- Wolfson Institute for Biomedical Research (WIBR); UCL; London WC1E 6BT UK
| | - Gabriel Waksman
- Institute of Structural and Molecular Biology (ISMB); UCL and Birkbeck College; London WC1E 7HX UK
| | - Han Remaut
- Structural and Molecular Microbiology; Structural Biology Research Center; VIB; Pleinlaan 2 Brussels 1050 Belgium
- Structural Biology Brussels; Vrije Universiteit Brussel; Pleinlaan 2 Brussels 1050 Belgium
| |
Collapse
|
29
|
Jakob RP, Koch JR, Burmann BM, Schmidpeter PAM, Hunkeler M, Hiller S, Schmid FX, Maier T. Dimeric Structure of the Bacterial Extracellular Foldase PrsA. J Biol Chem 2014; 290:3278-92. [PMID: 25525259 DOI: 10.1074/jbc.m114.622910] [Citation(s) in RCA: 34] [Impact Index Per Article: 3.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/17/2022] Open
Abstract
Secretion of proteins into the membrane-cell wall space is essential for cell wall biosynthesis and pathogenicity in Gram-positive bacteria. Folding and maturation of many secreted proteins depend on a single extracellular foldase, the PrsA protein. PrsA is a 30-kDa protein, lipid anchored to the outer leaflet of the cell membrane. The crystal structure of Bacillus subtilis PrsA reveals a central catalytic parvulin-type prolyl isomerase domain, which is inserted into a larger composite NC domain formed by the N- and C-terminal regions. This domain architecture resembles, despite a lack of sequence conservation, both trigger factor, a ribosome-binding bacterial chaperone, and SurA, a periplasmic chaperone in Gram-negative bacteria. Two main structural differences are observed in that the N-terminal arm of PrsA is substantially shortened relative to the trigger factor and SurA and in that PrsA is found to dimerize in a unique fashion via its NC domain. Dimerization leads to a large, bowl-shaped crevice, which might be involved in vivo in protecting substrate proteins from aggregation. NMR experiments reveal a direct, dynamic interaction of both the parvulin and the NC domain with secretion propeptides, which have been implicated in substrate targeting to PrsA.
Collapse
Affiliation(s)
- Roman P Jakob
- From the Biozentrum, Universität Basel, Klingelbergstrasse 50/70, 4056 Basel, Switzerland and
| | - Johanna R Koch
- the Laboratorium für Biochemie and Bayreuther Zentrum für Molekulare Biowissenschaften, Universität Bayreuth, Universitätsstrasse 30, 95440 Bayreuth, Germany
| | - Björn M Burmann
- From the Biozentrum, Universität Basel, Klingelbergstrasse 50/70, 4056 Basel, Switzerland and
| | - Philipp A M Schmidpeter
- the Laboratorium für Biochemie and Bayreuther Zentrum für Molekulare Biowissenschaften, Universität Bayreuth, Universitätsstrasse 30, 95440 Bayreuth, Germany
| | - Moritz Hunkeler
- From the Biozentrum, Universität Basel, Klingelbergstrasse 50/70, 4056 Basel, Switzerland and
| | - Sebastian Hiller
- From the Biozentrum, Universität Basel, Klingelbergstrasse 50/70, 4056 Basel, Switzerland and
| | - Franz X Schmid
- the Laboratorium für Biochemie and Bayreuther Zentrum für Molekulare Biowissenschaften, Universität Bayreuth, Universitätsstrasse 30, 95440 Bayreuth, Germany
| | - Timm Maier
- From the Biozentrum, Universität Basel, Klingelbergstrasse 50/70, 4056 Basel, Switzerland and
| |
Collapse
|
30
|
Blank BS, Abi Abdallah DS, Park JJ, Nazarova EV, Pavinski Bitar A, Maurer KJ, Marquis H. Misregulation of the broad-range phospholipase C activity increases the susceptibility of Listeria monocytogenes to intracellular killing by neutrophils. Microbes Infect 2014; 16:104-13. [PMID: 24513703 DOI: 10.1016/j.micinf.2013.10.014] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/26/2013] [Revised: 09/05/2013] [Accepted: 10/16/2013] [Indexed: 10/26/2022]
Abstract
Listeria monocytogenes is a facultative intracellular bacterial pathogen that tightly regulates the activities of various virulence factors during infection. A mutant strain (the plcBDpro mutant) that has lost the ability to control the activity of a phospholipase C (PC-PLC) is attenuated a hundred fold in mice. This attenuation is not due to a lack of bacterial fitness, but appears to result from a modified host response to infection. The transcriptomic pattern of immune-related genes indicated that PC-PLC did not enhance the innate immune response in infected macrophages. However, it partially protected the cells from bacteria-mediated mitochondrial fragmentation. In mice, the plcBDpro mutant transiently caused an increase in liver pathology, as judged by the size of neutrophil-filled micro-abscesses. Moreover, the plcBDpro mutant was more susceptible to intracellular killing by neutrophils than wild-type L. monocytogenes. Together, these data indicate that in vivo attenuation of the plcBDpro mutant results from its reduced ability to disrupt mitochondrial homeostasis and to resist intracellular killing by neutrophils.
Collapse
|
31
|
Xayarath B, Freitag NE. Optimizing the balance between host and environmental survival skills: lessons learned from Listeria monocytogenes. Future Microbiol 2014; 7:839-52. [PMID: 22827306 DOI: 10.2217/fmb.12.57] [Citation(s) in RCA: 41] [Impact Index Per Article: 4.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/19/2022] Open
Abstract
Environmental pathogens - organisms that survive in the outside environment but maintain the capacity to cause disease in mammals - navigate the challenges of life in habitats that range from water and soil to the cytosol of host cells. The bacterium Listeria monocytogenes has served for decades as a model organism for studies of host-pathogen interactions and for fundamental paradigms of cell biology. This ubiquitous saprophyte has recently become a model for understanding how an environmental bacterium switches to life within human cells. This review describes how L. monocytogenes balances life in disparate environments with the help of a critical virulence regulator known as PrfA. Understanding L. monocytogenes survival strategies is important for gaining insight into how environmental microbes become pathogens.
Collapse
Affiliation(s)
- Bobbi Xayarath
- Department of Microbiology & Immunology, University of Illinois at Chicago, Chicago, IL, USA
| | | |
Collapse
|
32
|
Blachechen LS, Fardim P, Petri DFS. Multifunctional cellulose beads and their interaction with gram positive bacteria. Biomacromolecules 2014; 15:3440-8. [PMID: 25100636 DOI: 10.1021/bm5009876] [Citation(s) in RCA: 15] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/30/2022]
Abstract
Cellulose beads with ∼3 mm of diameter and high circularity were obtained by dripping cellulose solutions (5, 6, and 7 wt %) dissolved in NaOH7%/urea12%, into HCl 2 M coagulation bath. Carboxylic groups were generated on beads surface through NaClO/NaClO2/TEMPO oxidation method, achieving total charge density of ∼0.77 mmol/g. Pristine (CB) and oxidized (OCB) beads were characterized by means of optical images analyses, scanning electron microscopy (SEM) and compression tests. Both types of beads, CB and OCB, were used as adsorbent for poly(4-vinyl-N-pentylpyridinium) bromide, QPVP-C5, a bactericidal agent. The adsorption of QPVP-C5 on CB and OCB was evaluated by means of FTIR-ATR, UV-vis, CHN elemental analyses, and X-ray photoelectron spectroscopy (XPS). The adsorbed amount of QPVP-C5 was remarkably higher on OCB than on CB due to ionic interactions. Desorption was less than 5%. The interaction between neat OCB or OCB coated and two different amounts of QPVP-C5 and Gram-positive bacteria Micrococcus luteus was assessed by changes in turbidimetry, SEM, and elemental analyses. Bacteria adsorbed on the surface of neat OCB and weakly QPVP-C5 coated OCB due to hydrogen bonding or ion-dipole interaction. Notorious bactericidal action was observed for OCB samples coated with large amount of QPVP-C5.
Collapse
Affiliation(s)
- Leandro S Blachechen
- Instituto de Química, Universidade de São Paulo , Av. Prof. Lineu Prestes 748, 05508-000 São Paulo, SP Brazil
| | | | | |
Collapse
|
33
|
Cahoon LA, Freitag NE. Listeria monocytogenes virulence factor secretion: don't leave the cell without a chaperone. Front Cell Infect Microbiol 2014; 4:13. [PMID: 24575392 PMCID: PMC3921577 DOI: 10.3389/fcimb.2014.00013] [Citation(s) in RCA: 26] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/01/2013] [Accepted: 01/25/2014] [Indexed: 11/13/2022] Open
Abstract
In Gram-positive bacteria, the secretion of proteins requires translocation of polypeptides across the bacterial membrane into the highly charged environment of the membrane-cell wall interface. Here, proteins must be folded and often further delivered across the matrix of the cell wall. While many aspects of protein secretion have been well studied in Gram-negative bacteria which possess both an inner and outer membrane, generally less attention has been given to the mechanics of protein secretion across the single cell membrane of Gram-positive bacteria. In this review, we focus on the role of a post-translocation secretion chaperone in Listeria monocytogenes known as PrsA2, and compare what is known regarding PrsA2 with PrsA homologs in other Gram-positive bacteria. PrsA2 is a member of a family of membrane-associated lipoproteins that contribute to the folding and stability of secreted proteins as they cross the bacterial membrane. PrsA2 contributes to the integrity of the L. monocytogenes cell wall as well as swimming motility and bacterial resistance to osmotic stress; however its most critical role may be its requirement for L. monocytogenes virulence and viability within host cells. A better understanding of the role of PrsA2 and PrsA-like homologs will provide insight into the dynamics of protein folding and stability in Gram-positive bacteria and may result in new strategies for optimizing protein secretion as well as inhibiting the production of virulence factors.
Collapse
Affiliation(s)
- Laty A Cahoon
- Department of Microbiology and Immunology, University of Illinois at Chicago Chicago, IL, USA
| | - Nancy E Freitag
- Department of Microbiology and Immunology, University of Illinois at Chicago Chicago, IL, USA
| |
Collapse
|
34
|
Wiegand S, Voigt B, Albrecht D, Bongaerts J, Evers S, Hecker M, Daniel R, Liesegang H. Fermentation stage-dependent adaptations of Bacillus licheniformis during enzyme production. Microb Cell Fact 2013; 12:120. [PMID: 24313996 PMCID: PMC3878961 DOI: 10.1186/1475-2859-12-120] [Citation(s) in RCA: 17] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/26/2013] [Accepted: 12/01/2013] [Indexed: 11/10/2022] Open
Abstract
Background Industrial fermentations can generally be described as dynamic biotransformation processes in which microorganisms convert energy rich substrates into a desired product. The knowledge of active physiological pathways, reflected by corresponding gene activities, allows the identification of beneficial or disadvantageous performances of the microbial host. Whole transcriptome RNA-Seq is a powerful tool to accomplish in-depth quantification of these gene activities, since the low background noise and the absence of an upper limit of quantification allow the detection of transcripts with high dynamic ranges. Such data enable the identification of potential bottlenecks and futile energetic cycles, which in turn can lead to targets for rational approaches to productivity improvement. Here we present an overview of the dynamics of gene activity during an industrial-oriented fermentation process with Bacillus licheniformis, an important industrial enzyme producer. Thereby, valuable insights which help to understand the complex interactions during such processes are provided. Results Whole transcriptome RNA-Seq has been performed to study the gene expression at five selected growth stages of an industrial-oriented protease production process employing a germination deficient derivative of B. licheniformis DSM13. Since a significant amount of genes in Bacillus strains are regulated posttranscriptionally, the generated data have been confirmed by 2D gel-based proteomics. Regulatory events affecting the coordinated activity of hundreds of genes have been analyzed. The data enabled the identification of genes involved in the adaptations to changing environmental conditions during the fermentation process. A special focus of the analyses was on genes contributing to central carbon metabolism, amino acid transport and metabolism, starvation and stress responses and protein secretion. Genes contributing to lantibiotics production and Tat-dependent protein secretion have been pointed out as potential optimization targets. Conclusions The presented data give unprecedented insights into the complex adaptations of bacterial production strains to the changing physiological demands during an industrial-oriented fermentation. These are, to our knowledge, the first publicly available data that document quantifiable transcriptional responses of the commonly employed production strain B. licheniformis to changing conditions over the course of a typical fermentation process in such extensive depth.
Collapse
Affiliation(s)
| | | | | | | | | | | | | | - Heiko Liesegang
- Department of Genomic and Applied Microbiology & Göttingen Genomics Laboratory, Institut für Mikrobiologie und Genetik, Norddeutsches Zentrum für Mikrobielle Genomforschung, Georg-August-Universität Göttingen, Grisebachstr, 8, D-37077 Göttingen, Germany.
| |
Collapse
|
35
|
Krawczyk-Balska A, Lipiak M. Critical role of a ferritin-like protein in the control of Listeria monocytogenes cell envelope structure and stability under β-lactam pressure. PLoS One 2013; 8:e77808. [PMID: 24204978 PMCID: PMC3812014 DOI: 10.1371/journal.pone.0077808] [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: 04/28/2013] [Accepted: 09/05/2013] [Indexed: 02/08/2023] Open
Abstract
The human pathogen Listeria monocytogenes is susceptible to the β-lactam antibiotics penicillin G and ampicillin, and these are the drugs of choice for the treatment of listerial infections. However, these antibiotics exert only a bacteriostatic effect on this bacterium and consequently, L. monocytogenes is regarded as β-lactam tolerant. It is widely accepted that the phenomenon of bacterial tolerance to β-lactams is due to the lack of adequate autolysin activity, but the mechanisms of L. monocytogenes tolerance to this class of antibiotics are poorly characterized. A ferritin-like protein (Fri) was recently identified as a mediator of β-lactam tolerance in L. monocytogenes, but its function in this process remains unknown. The present study was undertaken to improve our understanding of L. monocytogenes tolerance to β-lactams and to characterize the role of Fri in this phenomenon. A comparative physiological analysis of wild-type L. monocytogenes and a fri deletion mutant provided evidence of a multilevel mechanism controlling autolysin activity in cells grown under β-lactam pressure, which leads to a reduction in the level and/or activity of cell wall-associated autolysins. This is accompanied by increases in the amount of teichoic acids, cell wall thickness and cell envelope integrity of L. monocytogenes grown in the presence of penicillin G, and provides the basis for the innate β-lactam tolerance of this bacterium. Furthermore, this study revealed the inability of the L. monocytogenes Δ fri mutant to deplete autolysins from the cell wall, to adjust the content of teichoic acids and to maintain their D-alanylation at the correct level when treated with penicillin G, thus providing further evidence that Fri is involved in the control of L. monocytogenes cell envelope structure and stability under β-lactam pressure.
Collapse
Affiliation(s)
- Agata Krawczyk-Balska
- Department of Applied Microbiology, Faculty of Biology, University of Warsaw, Warsaw, Poland
| | - Magdalena Lipiak
- Department of Applied Microbiology, Faculty of Biology, University of Warsaw, Warsaw, Poland
| |
Collapse
|
36
|
Forster BM, Bitar AP, Marquis H. A non-catalytic histidine residue influences the function of the metalloprotease of Listeria monocytogenes. MICROBIOLOGY-SGM 2013; 160:142-148. [PMID: 24140648 DOI: 10.1099/mic.0.071779-0] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 10/26/2022]
Abstract
Mpl, a thermolysin-like metalloprotease, and PC-PLC, a phospholipase C, are synthesized as proenzymes by the intracellular bacterial pathogen Listeria monocytogenes. During intracellular growth, L. monocytogenes is temporarily confined in a membrane-bound vacuole whose acidification leads to Mpl autolysis and Mpl-mediated cleavage of the PC-PLC N-terminal propeptide. Mpl maturation also leads to the secretion of both Mpl and PC-PLC across the bacterial cell wall. Previously, we identified negatively charged and uncharged amino acid residues within the N terminus of the PC-PLC propeptide that influence the ability of Mpl to mediate the maturation of PC-PLC, suggesting that these residues promote the interaction of the PC-PLC propeptide with Mpl. In the present study, we identified a non-catalytic histidine residue (H226) that influences Mpl secretion across the cell wall and its ability to process PC-PLC. Our results suggest that a positive charge at position 226 is required for Mpl functions other than autolysis. Based on the charge requirement at this position, we hypothesize that this residue contributes to the interaction of Mpl with the PC-PLC propeptide.
Collapse
Affiliation(s)
- Brian M Forster
- Department of Microbiology and Immunology, Cornell University, Ithaca, NY 14853, USA
| | - Alan Pavinski Bitar
- Department of Microbiology and Immunology, Cornell University, Ithaca, NY 14853, USA
| | - Hélène Marquis
- Department of Microbiology and Immunology, Cornell University, Ithaca, NY 14853, USA
| |
Collapse
|
37
|
Engineering signal peptides for enhanced protein secretion from Lactococcus lactis. Appl Environ Microbiol 2012; 79:347-56. [PMID: 23124224 DOI: 10.1128/aem.02667-12] [Citation(s) in RCA: 56] [Impact Index Per Article: 4.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022] Open
Abstract
Lactococcus lactis is an attractive vehicle for biotechnological production of proteins and clinical delivery of therapeutics. In many such applications using this host, it is desirable to maximize secretion of recombinant proteins into the extracellular space, which is typically achieved by using the native signal peptide from a major secreted lactococcal protein, Usp45. In order to further increase protein secretion from L. lactis, inherent limitations of the Usp45 signal peptide (Usp45sp) must be elucidated. Here, we performed extensive mutagenesis on Usp45sp to probe the effects of both the mRNA sequence (silent mutations) and the peptide sequence (amino acid substitutions) on secretion. We screened signal peptides based on their resulting secretion levels of Staphylococcus aureus nuclease and further evaluated them for secretion of Bacillus subtilis α-amylase. Silent mutations alone gave an increase of up to 16% in the secretion of α-amylase through a mechanism consistent with relaxed mRNA folding around the ribosome binding site and enhanced translation. Targeted amino acid mutagenesis in Usp45sp, combined with additional silent mutations from the best clone in the initial screen, yielded an increase of up to 51% in maximum secretion of α-amylase while maintaining secretion at lower induction levels. The best sequence from our screen preserves the tripartite structure of the native signal peptide but increases the positive charge of the n-region. Our study presents the first example of an engineered L. lactis signal peptide with a higher secretion yield than Usp45sp and, more generally, provides strategies for further enhancing protein secretion in bacterial hosts.
Collapse
|