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Aono R, Emi S, Okabe-Watanabe K, Nariya H, Matsunaga N, Hitsumoto Y, Katayama S. Autolysin as a fibronectin receptor on the cell surface of Clostridium perfringens. Anaerobe 2023; 83:102769. [PMID: 37544355 DOI: 10.1016/j.anaerobe.2023.102769] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/06/2023] [Revised: 06/30/2023] [Accepted: 07/24/2023] [Indexed: 08/08/2023]
Abstract
OBJECTIVE Clostridium perfringens causes food poisoning and gas gangrene, a serious wound-associated infection. C. perfringens cells adhere to collagen via fibronectin (Fn). We investigated whether the peptidoglycan hydrolase of C. perfringens, i.e., autolysin (Acp), is implicated in Fn binding to C. perfringens cells. METHODS This study used recombinant Acp fragments, human Fn and knockout mutants (C. perfringens 13 acp::erm and HN13 ΔfbpC ΔfbpD). Ligand blotting, Western blotting analysis, and complementation tests were performed. The Fn-binding activity of each mutant was evaluated by ELISA. RESULTS From an Fn-binding assay using recombinant Acp fragments, Fn was found to bind to the catalytic domain of Acp. In mutant cells lacking Acp, Fn binding was significantly decreased, but was restored by the complementation of the acp gene. There are three known kinds of Fn-binding proteins in C. perfringens: FbpC, FbpD, and glyceraldehyde-3-phosphate dehydrogenase. We found no difference in Fn-binding activity between the mutant cells lacking both FbpC and FbpD (SAK3 cells) and the wild-type cells, indicating that these Fn-binding proteins are not involved in Fn binding to C. perfringens cells. CONCLUSIONS We found that the Acp is an Fn-binding protein that acts as an Fn receptor on the surface of C. perfringens cells.
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Affiliation(s)
- Riyo Aono
- Department of Material Science, School of Science, Faculty of Science, Okayama University of Science, 1-1 Ridai-cho, Kita-ku, Okayama-shi, Okayama, 700-0005, Japan
| | - Shogo Emi
- Department of Life Science, Faculty of Science, Okayama University of Science, 1-1 Ridai-cho, Kita-ku, Okayama-shi, Okayama, 700-0005, Japan
| | - Kanako Okabe-Watanabe
- Department of Medical Technology, Faculty of Health Science and Technology, Kawasaki University of Medical Welfare, 288 Matsushima, Kurashiki-shi, Okayama, 701-0193, Japan
| | - Hirofumi Nariya
- Laboratory of Food Microbiology, Graduate School of Human Life Science, Jumonji University, 2-1-28 Sugasawa, Niiza-shi, Saitama, 352-8510, Japan
| | - Nozomu Matsunaga
- Department of Life Science, Faculty of Science, Okayama University of Science, 1-1 Ridai-cho, Kita-ku, Okayama-shi, Okayama, 700-0005, Japan
| | - Yasuo Hitsumoto
- Department of Life Science, Faculty of Science, Okayama University of Science, 1-1 Ridai-cho, Kita-ku, Okayama-shi, Okayama, 700-0005, Japan
| | - Seiichi Katayama
- Department of Life Science, Faculty of Science, Okayama University of Science, 1-1 Ridai-cho, Kita-ku, Okayama-shi, Okayama, 700-0005, Japan.
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2
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Findinier J. Autolysin Production from Chlamydomonas reinhardtii. Bio Protoc 2023; 13:e4705. [PMID: 37449035 PMCID: PMC10336564 DOI: 10.21769/bioprotoc.4705] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/09/2023] [Revised: 02/26/2023] [Accepted: 04/16/2023] [Indexed: 07/18/2023] Open
Abstract
Chlamydomonas reinhardtii is a model organism for various processes, from photosynthesis to cilia biogenesis, and a great chassis to learn more about biofuel production. This is due to the width of molecular tools available, which have recently expanded with the development of a modular cloning system but, most importantly, with CRISPR/Cas9 editing now being possible. This technique has proven to be more efficient in the absence of a cell wall by using specific mutants or by digesting Chlamydomonas cell wall using the mating-specific metalloprotease autolysin (also called gametolysin). Multiple protocols have been used and shared for autolysin production from Chlamydomonas cells; however, they provide very inconsistent results, which hinders the capacity to routinely perform CRISPR mutagenesis. Here, we propose a simple protocol for autolysin production requiring transfer of cells from plates into a dense liquid suspension, gametogenesis by overnight incubation before mixing of gametes, and enzyme harvesting after 2 h. This protocol has shown to be highly efficient for autolysin production regardless of precise control over cell density at any step. Requiring a minimal amount of labor, it will provide a simple, ready-to-go approach to produce an enzyme critical for the generation of targeted mutants.
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Affiliation(s)
- Justin Findinier
- Biology Science & Engineering, Carnegie Institution of Washington, Stanford, USA
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3
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Dehnavi M, Haghighat S, Yazdi MH, Mahdavi M. Glucomannan as a polysaccharide adjuvant improved immune responses against Staphylococcus aureus: Potency and efficacy studies. Microb Pathog 2023; 176:106007. [PMID: 36709850 DOI: 10.1016/j.micpath.2023.106007] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/30/2021] [Revised: 01/24/2023] [Accepted: 01/25/2023] [Indexed: 01/28/2023]
Abstract
Staphylococcus aureus is a gram-positive bacterium, representing one of the most important nosocomial pathogens. The treatment of infections, caused by S. aureus, has become increasingly intricate due to the emergence of highly resistant strains. Therefore, it is obvious that an effective prevention strategy against this bacterium could significantly decrease such infections. In the present study, the protective efficacy and immunological properties of recombinant autolysin, formulated in Montanide ISA266 and Alum adjuvants with Glucomannan as a polysaccharide, were assessed in the systemic mouse model of infection. Mice were immunized with the purified recombinant protein in various formulations in different groups and, subsequently, mice were challenged with 5 × 108 CFU of bacteria for the evaluation of their survival and bacterial clearances in the internal organs. ELISA was performed to determine the type of induced immunity, cytokine secretion (IFN-γ, IL-4, IL-2, and IL-17), and isotyping (IgG1 and IgG2a). In addition, we measured the opsonophagocytic activities of the antibodies. Results showed that immunization with r-autolysin + Alum + Glucomannan and r-autolysin + MontanideISA266+Glucomannan formulations significantly increased total IgG and isotypes (IgG1 and IgG2a), as compared with other vaccinated and control groups. Furthermore, the formulation of r-autolysin in Alum and MontanideISA266 adjuvants with Glucomannan enhanced IFN-γ, IL-4, and IL-17 cytokine secretion as well as protectivity, following experimental challenge. We concluded that Glucomannan has the potential to induce immune responses and would be used as an adjuvant factor in vaccine formulation.
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Affiliation(s)
- Meghdad Dehnavi
- Department of Microbiology, Faculty of Pharmaceutical Sciences, Tehran Medical Sciences, Islamic Azad University, Tehran, Iran
| | - Setareh Haghighat
- Department of Microbiology, Faculty of Advanced Science and Technology, Tehran Medical Sciences, Islamic Azad University, Tehran, Iran.
| | - Mohammad Hossein Yazdi
- Biotechnology Research Center, Faculty of Pharmacy, Tehran University of Medical Sciences, Tehran, Iran; Immunotherapy Group, The Institute of Pharmaceutical Sciences (TIPS), Tehran University of Medical Sciences, Tehran, Iran; Recombinant Vaccine Research Center, Tehran University of Medical Sciences, Tehran, Iran
| | - Mehdi Mahdavi
- Advanced Therapy Medicinal Product (ATMP) Department, Breast Cancer Research Center, Motamed Cancer Institute, Academic Center for Education, Culture and Research (ACECR), Tehran, Iran; Department of Immunology, Pasteur Institute of Iran, Tehran, Iran
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Ranjbariyan A, Haghighat S, Yazdi MH, Arbabi Bidgoli S. Synthetic selenium nanoparticles as co-adjuvant improved immune responses against methicillin-resistant Staphylococcus aureus. World J Microbiol Biotechnol 2022; 39:16. [PMID: 36401129 DOI: 10.1007/s11274-022-03455-6] [Citation(s) in RCA: 1] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Abstract] [Key Words] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/15/2022] [Accepted: 11/01/2022] [Indexed: 11/21/2022]
Abstract
Methicillin-resistant Staphylococcus aureus (MRSA) is one of the leading causes of hospital-acquired infections worldwide, which is resistant to many antibiotics, resulting in significant mortality in societies. Vaccination is a well-known approach to preventing disease. Autolysin, a surface-associated protein in S. aureus with multiple functions, is a suitable candidate for vaccine development. As a co-adjuvant, selenium nanoparticles (SeNPs) can increase the immune system, presumably resulting in increased vaccine efficacy. The present study evaluated the immunogenicity and defense of recombinant autolysin formulated in SeNPs and Alum adjuvants against MRSA. r-Autolysin was expressed and purified by the Ni-NTA affinity chromatography. SeNPs were synthetically obtained from sodium dioxide, followed by an assessment of shape and size using SEM and DLS. Balb/c mice were injected subcutaneously with 20 mg of r-autolysin formulated in Alum and SeNps adjuvants three times with the proper control group in 2 weeks intervals. Cytokine profile and isotyping ELISA were conducted to determine the type of induced immunity. Opsonophagocytosis tests assessed the functional activity of the vaccine, and the bacterial burden from the infected tissues was determined. Results showed that mice receiving SeNps and r-Autolysin had higher levels of total IgG and isotypes (IgG1 and IgG2a) and increased cytokine levels (IFN-γ, TNF-α, IL-12, and IL-4) as compared with those only receiving autolysin and PBS as a control. More importantly, mice immunized with SeNps and r-Autolysin exhibited a decrease in mortality and bacterial burden compared to the control group. We concluded that SeNps could stimulate immune responses and can be used as an adjuvant element in vaccine formulation.
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Wang M, Deng Z, Li Y, Ma Y, Wang J. Design and characterization of a novel lytic protein against Clostridium difficile. Appl Microbiol Biotechnol 2022; 106:4511-4521. [PMID: 35699735 PMCID: PMC9194777 DOI: 10.1007/s00253-022-12010-0] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/21/2022] [Revised: 05/29/2022] [Accepted: 06/01/2022] [Indexed: 11/29/2022]
Abstract
Abstract Clostridium difficile (C. difficile) is a Gram-positive, spore-forming, toxin-producing anaerobe that can cause nosocomial antibiotic-associated intestinal disease. Autolysin is a lytic enzyme that hydrolyzes peptidoglycans of the bacterial cell wall, with a catalytic domain and cell wall–binding domains, proven to be involved in bacterial cell wall remodeling and cell division. Although autolysins in C. difficile have been reported, the autolysins have failed to yield impressive results when used as exogenous lytic agents. In this study, we expressed and characterized the binding domains (Cwp19-BD and Acd-BD) and catalytic domains (Cwp19-CD, Acd-CD, and Cwl-CD) of C. difficile autolysins, and the domains with the best binding specificity and lytic activity were selected towards C. difficile to design a novel lytic protein Cwl-CWB2. Cwl-CWB2 showed good biosafety with significantly low hemolysis and without cytotoxicity. The results of fluorescence analysis and lytic assay demonstrated that Cwl-CWB2 has higher binding specificity and stronger lytic activity with a minimum inhibitory concentration at 13.39 ± 5.80 μg/mL against living C. difficile cells, which is significantly stronger than commercial lysozyme (3333.33 ± 1443.37 μg/mL) and other reported C. difficile autolysins. Besides, Cwl-CWB2 exhibited good stability as about 75% of the lytic activity was still retained when incubated at 37 °C for 96 h, which is considered to be a potential antimicrobial agent to combat C. difficile. Key points • Several binding domains and catalytic domains, deriving from several Clostridium difficile autolysins, were expressed, purified, and functionally characterized. • A novel C. difficile lytic protein Cwl-CWB2 was designed from C. difficile autolysins. • The binding specificity and lytic activity of Cwl-CWB2 against C. difficile showed advantages compared with other reported C. difficile autolysins. • Cwl-CWB2 exhibited significantly low hemolysis and cytotoxicity against normal-derived colon mucosa 460 cell. Graphical abstract ![]()
Supplementary Information The online version contains supplementary material available at 10.1007/s00253-022-12010-0.
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Affiliation(s)
- Meng Wang
- School of Biology and Biological Engineering, South China University of Technology, Guangzhou, 510006, China
| | - Zifeng Deng
- School of Biology and Biological Engineering, South China University of Technology, Guangzhou, 510006, China
| | - Yanmei Li
- School of Biology and Biological Engineering, South China University of Technology, Guangzhou, 510006, China
| | - Yi Ma
- School of Biology and Biological Engineering, South China University of Technology, Guangzhou, 510006, China
- Guangdong Key Laboratory of Fermentation and Enzyme Engineering, South China University of Technology, Guangzhou, 510006, China
| | - Jufang Wang
- School of Biology and Biological Engineering, South China University of Technology, Guangzhou, 510006, China.
- Guangdong Key Laboratory of Fermentation and Enzyme Engineering, South China University of Technology, Guangzhou, 510006, China.
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Haghighat S, Siadat SD, Akhavan Sepahi A, Mahdavi M. Recombinant PBP2a/ autolysin conjugate as PLGA-based nanovaccine induced humoral responses with opsonophagocytosis activity, and protection versus methicillin-resistant Staphylococcus aureus infection. Iran J Basic Med Sci 2022; 25:442-450. [PMID: 35656080 PMCID: PMC9150805 DOI: 10.22038/ijbms.2022.59992.13303] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 08/28/2021] [Accepted: 04/05/2022] [Indexed: 11/10/2022]
Abstract
Objectives Methicillin-resistant Staphylococcus aureus (MRSA) reasons extreme infections, can resist various conventional antimicrobial agents, and cause morbidity and mortality worldwide. Vaccination seems to help modulate MRSA infections. Nanovaccine is considered a novel strategy in vaccine technology. The primary purpose of the present study was to develop a conjugate vaccine based on recombinant PBP2a and MRSA autolysin formulated in PLGA as a nanoparticle capable of enhancing protective responses against MRSA in the murine model. Materials and Methods Recombinant PBP2a and autolysin have been expressed and purified by nickel-nitrilotriacetic acid (Ni-NTA) affinity column and characterized by SDS-PAGE and western blot. PLGA was bound to recombinant proteins by using 1-ethyl-3-(3-dimethylaminopropyl) carbodiimide hydrochloride (EDAC) and adipic acid dihydrazide (ADH) as a linker and spacer, respectively. Conjugation of recombinant proteins to PLGA was confirmed by the AFM assay, zeta potential, and size distribution, and its efficacy was evaluated in mice. Total IgG, IgG1, IgG2a, IgG2b, and IgM titers were analyzed to assess immune responses. Lastly, the bioactivity of antibodies was tested by using the opsonophagocytosis assay. Results Mice immunized with the r-PBP2a-r-autolysin-PLGA nanovaccine led to increased levels of opsonic antibodies and IgG1, IgG2a, IgG2b, and IgM when compared with other experimental groups. Our results confirmed that vaccination with nanovaccine could reduce the mortality rate against the sub-lethal dose of MRSA challenge. Furthermore, the nanovaccine could eliminate MRSA from the kidney of infected mice. Conclusion This study may provide valuable insights into the protective power of the r-PBP2a-r-autolysin-PLGA conjugate vaccine against MRSA infection.
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Affiliation(s)
- Setareh Haghighat
- Department of Microbiology, Faculty of Advanced Science and Technology, Tehran Medical Sciences, Islamic Azad University, Tehran, Iran,Corresponding author: Setareh Haghighat. Department of Microbiology, Faculty of Advanced Science and Technology, Tehran Medical Sciences, Islamic Azad University, Tehran, Iran. ;
| | - Seyed Davar Siadat
- Department of Mycobacteriology & Pulmonary Research, Microbiology Research Center, Pasteur Institute of Iran, Tehran, Iran
| | - Abbas Akhavan Sepahi
- Department of Microbiology, Faculty of Basic Sciences, North Tehran Branch, Islamic Azad University, Tehran, Iran
| | - Mehdi Mahdavi
- Advanced Therapy Medicinal Product (ATMP) Department, Breast Cancer Research Center, Motamed Cancer Institute, Academic Center for Education, Culture and Research(ACECR), Tehran, Iran,Recombinant Vaccine Research Center, Tehran University of Medical Sciences, Tehran, Iran,Immunotherapy Group, The Institute of Pharmaceutical Sciences (TIPS), Tehran University of Medical Sciences, Tehran, Iran
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Hirayama S, Domon H, Hiyoshi T, Isono T, Tamura H, Sasagawa K, Takizawa F, Terao Y. Triosephosphate isomerase of Streptococcus pneumoniae is released extracellularly by autolysis and binds to host plasminogen to promote its activation. FEBS Open Bio 2022; 12:1206-1219. [PMID: 35298875 PMCID: PMC9157410 DOI: 10.1002/2211-5463.13396] [Citation(s) in RCA: 5] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/17/2021] [Revised: 03/04/2022] [Accepted: 03/15/2022] [Indexed: 11/24/2022] Open
Abstract
Recruitment of plasminogen is an important infection strategy of the human pathogen Streptococcus pneumoniae to invade host tissues. In Streptococcus aureus, triosephosphate isomerase (TPI) has been reported to bind plasminogen. In this study, the TPI of S. pneumoniae (TpiA) was identified through proteomic analysis of bronchoalveolar lavage fluid from a murine pneumococcal pneumonia model. The binding kinetics of recombinant pneumococcal TpiA with plasminogen were characterized using surface plasmon resonance (SPR, Biacore), ligand blot analyses, and enzyme‐linked immunosorbent assay. Enhanced plasminogen activation and subsequent degradation by plasmin were also shown. Release of TpiA into the culture medium was observed to be dependent on autolysin. These findings suggest that S. pneumoniae releases TpiA via autolysis, which then binds to plasminogen and promotes its activation, thereby contributing to tissue invasion via degradation of the extracellular matrix.
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Affiliation(s)
- Satoru Hirayama
- Division of Microbiology and Infectious Diseases, Niigata University Graduate School of Medical and Dental Sciences, Niigata, Japan
| | - Hisanori Domon
- Division of Microbiology and Infectious Diseases, Niigata University Graduate School of Medical and Dental Sciences, Niigata, Japan.,Center for Advanced Oral Science, Niigata University Graduate School of Medical and Dental Sciences, Niigata, Japan
| | - Takumi Hiyoshi
- Division of Microbiology and Infectious Diseases, Niigata University Graduate School of Medical and Dental Sciences, Niigata, Japan.,Center for Advanced Oral Science, Niigata University Graduate School of Medical and Dental Sciences, Niigata, Japan.,Division of Periodontology, Niigata University Graduate School of Medical and Dental Sciences, Niigata, Japan
| | - Toshihito Isono
- Division of Microbiology and Infectious Diseases, Niigata University Graduate School of Medical and Dental Sciences, Niigata, Japan
| | - Hikaru Tamura
- Division of Microbiology and Infectious Diseases, Niigata University Graduate School of Medical and Dental Sciences, Niigata, Japan.,Division of Periodontology, Niigata University Graduate School of Medical and Dental Sciences, Niigata, Japan
| | - Karin Sasagawa
- Division of Microbiology and Infectious Diseases, Niigata University Graduate School of Medical and Dental Sciences, Niigata, Japan.,Division of Periodontology, Niigata University Graduate School of Medical and Dental Sciences, Niigata, Japan
| | - Fumio Takizawa
- Division of Microbiology and Infectious Diseases, Niigata University Graduate School of Medical and Dental Sciences, Niigata, Japan.,Division of Periodontology, Niigata University Graduate School of Medical and Dental Sciences, Niigata, Japan
| | - Yutaka Terao
- Division of Microbiology and Infectious Diseases, Niigata University Graduate School of Medical and Dental Sciences, Niigata, Japan.,Center for Advanced Oral Science, Niigata University Graduate School of Medical and Dental Sciences, Niigata, Japan
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Cao S, Dou X, Zhang X, Fang Y, Yang Z, Jiang Y, Hao X, Zhang Z, Wang H. Streptococcus pneumoniae autolysin LytA inhibits ISG15 and ISGylation through decreasing bacterial DNA abnormally accumulated in the cytoplasm of macrophages. Mol Immunol 2021; 140:87-96. [PMID: 34673375 DOI: 10.1016/j.molimm.2021.09.011] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/03/2021] [Revised: 09/05/2021] [Accepted: 09/28/2021] [Indexed: 11/25/2022]
Abstract
Interferon stimulated gene 15 (ISG15) is one of the most robustly upregulated interferon stimulated genes (ISGs) and also a ubiquitin-like modifier which has been reported to play an important role in host defense against pathogens. Cytosolic nucleic acids detected by DNA sensors induce type Ⅰ interferons (IFN-Ⅰs) and ISGs in host cells. Streptococcus pneumoniae (S. pn) autolysin LytA triggers bacterial lysis and then S. pn-derived genomic DNA (hereafter referred to as S. pn-DNA) can be released and accumulates in the cytoplasm of host cells. However, it remains elusive whether LytA-mediated S. pn-DNA release is involved in ISG15 induction. Here we verified that ISG15 conjugation system can be widely activated by S. pn and cytosolic S. pn-DNA in host cells. Moreover, the phagocytosis of macrophages to the mutant strain S. pn D39 ΔlytA was enhanced when compared to S. pn D39, which in turn increased S. pn-DNA uptake into macrophages and augmented ISG15 expression. ISG15 might upregulate proinflammatory cytokines tumor necrosis factor α (TNF-α) and interleukin 1β (IL-1β) in macrophages and further promoted the clearance of S. pn in the absence of LytA. These results indicate that S. pn autolysis blunts ISG15 induction through preventing bacteria internalization and reducing cytosolic S. pn-DNA accumulation in macrophages, revealing a new strategy of S. pn for avoiding elimination. This study will help us to further understand the role of ISG15 during S. pn infection as well as the regulatory mechanisms of immune responses mediated by bacterial autolysis and bacterial DNA.
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Affiliation(s)
- Sijia Cao
- Key Laboratory of Diagnostic Medicine Designated by the Ministry of Education, Chongqing Medical University, Chongqing, 400016, China; School of Laboratory Medicine, Chongqing Medical University, Chongqing, 400016, China; Xiamen Maternal and Child Health Care Hospital, Xiamen, 361001 Fujian Province, China
| | - Xiaoyun Dou
- Institute of Life Sciences, Chongqing Medical University, Chongqing, 400016, China
| | - Xuemei Zhang
- Key Laboratory of Diagnostic Medicine Designated by the Ministry of Education, Chongqing Medical University, Chongqing, 400016, China; School of Laboratory Medicine, Chongqing Medical University, Chongqing, 400016, China
| | - Yuting Fang
- Key Laboratory of Diagnostic Medicine Designated by the Ministry of Education, Chongqing Medical University, Chongqing, 400016, China; School of Laboratory Medicine, Chongqing Medical University, Chongqing, 400016, China
| | - Zihan Yang
- Key Laboratory of Diagnostic Medicine Designated by the Ministry of Education, Chongqing Medical University, Chongqing, 400016, China; School of Laboratory Medicine, Chongqing Medical University, Chongqing, 400016, China
| | - Yinting Jiang
- Key Laboratory of Diagnostic Medicine Designated by the Ministry of Education, Chongqing Medical University, Chongqing, 400016, China; School of Laboratory Medicine, Chongqing Medical University, Chongqing, 400016, China
| | - Xiaoling Hao
- Key Laboratory of Diagnostic Medicine Designated by the Ministry of Education, Chongqing Medical University, Chongqing, 400016, China; School of Laboratory Medicine, Chongqing Medical University, Chongqing, 400016, China
| | - Ziyuan Zhang
- Key Laboratory of Diagnostic Medicine Designated by the Ministry of Education, Chongqing Medical University, Chongqing, 400016, China; School of Laboratory Medicine, Chongqing Medical University, Chongqing, 400016, China
| | - Hong Wang
- Key Laboratory of Diagnostic Medicine Designated by the Ministry of Education, Chongqing Medical University, Chongqing, 400016, China; School of Laboratory Medicine, Chongqing Medical University, Chongqing, 400016, China.
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Wang M, Li Z, Zhang Y, Li Y, Li N, Huang D, Xu B. Interaction with teichoic acids contributes to highly effective antibacterial activity of graphene oxide on Gram-positive bacteria. J Hazard Mater 2021; 412:125333. [PMID: 33951879 DOI: 10.1016/j.jhazmat.2021.125333] [Citation(s) in RCA: 12] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 11/11/2020] [Revised: 02/02/2021] [Accepted: 02/03/2021] [Indexed: 05/20/2023]
Abstract
Graphene oxide (GO) has high-efficient antibacterial activity to diverse pathogenic bacteria. However, the detailed antibacterial mechanism of GO is not fully clear. Herein the antibacterial properties of GO against model Gram-positive (Gram+) (Staphylococcus aureus and Staphylococcus epidermidis) and Gram-negative (Gram-) bacteria (Pseudomonas aeruginosa and Escherichia coli) were compared by plate count method. Results showed that 4 mg/L of GO induced the mortality of Gram+ and Gram- bacteria by > 99% and < 25%, respectively. GO had greater adsorption affinity to teichoic acids, the unique components existing in the cell wall of Gram+ bacteria, mainly via π-π interaction. The adsorption efficiency of teichoic acids was 27 times higher than that of peptidoglycan when they were simultaneously exposed to 100 mg/L GO. The superior adsorption of teichoic acids onto GO increased one order of magnitude of atlA expression, the autolysin related gene. As a result, these accelerated bacterial death by hydrolyzing peptidoglycan in cell walls. Exogenous addition of 50 mg/L teichoic acids could impair 4-5 fold of antibacterial activity of GO against S. aureus. These new findings illuminate the antibacterial mechanism of GO against Gram+ bacteria, which paves the way for the further application of graphene-based materials in water disinfection and pathogen control.
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Affiliation(s)
- Meizhen Wang
- School of Environmental Science and Engineering, Zhejiang Gongshang University, Hangzhou 310012, China; Zhejiang Provincial Key Laboratory of Solid Waste Treatment and Recycling, Hangzhou 310012, China
| | - Zhangqiang Li
- School of Environmental Science and Engineering, Zhejiang Gongshang University, Hangzhou 310012, China; Zhejiang Provincial Key Laboratory of Solid Waste Treatment and Recycling, Hangzhou 310012, China
| | - Yunyun Zhang
- School of Environmental Science and Engineering, Zhejiang Gongshang University, Hangzhou 310012, China
| | - Yue Li
- School of Environmental Science and Engineering, Zhejiang Gongshang University, Hangzhou 310012, China
| | - Na Li
- School of Environmental Science and Engineering, Zhejiang Gongshang University, Hangzhou 310012, China
| | - Dan Huang
- School of Environmental Science and Engineering, Zhejiang Gongshang University, Hangzhou 310012, China; Zhejiang Provincial Key Laboratory of Solid Waste Treatment and Recycling, Hangzhou 310012, China.
| | - Baile Xu
- Institut für Biologie, Freie Universität Berlin, Berlin D-14195, Germany
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10
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Buchad H, Nair M. The small RNA SprX regulates the autolysin regulator WalR in Staphylococcus aureus. Microbiol Res 2021; 250:126785. [PMID: 34000511 DOI: 10.1016/j.micres.2021.126785] [Citation(s) in RCA: 10] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/18/2020] [Revised: 04/29/2021] [Accepted: 04/30/2021] [Indexed: 10/21/2022]
Abstract
Pathogenesis of Staphylococcus aureus is attributed to its remarkable adaptation to changes in the environment, mediated by the arsenal of virulence factors, which are regulated by intricate mechanisms that include small RNAs (sRNAs) as important regulatory molecules. The sRNA SprX was previously described to be involved in the regulation of S. aureus pathogenicity, by modifying the expression of surface-associated clumping factor B and the secreted delta haemolysin. This study describes the regulation by SprX, of expression of multiple autolysins, which play an essential role in cell wall metabolism and function as important virulence factors that facilitate adhesion, internalization, and immune evasion during S. aureus colonization and pathogenesis. SprX acts by positively regulating the expression of autolysin regulator WalR. Overexpression of SprX resulted in differential regulation of autolysins IsaA, and LytM, while WalR levels were unchanged. SprX knockdown strain exhibited down-regulation of multiple autolytic bands corresponding to the major autolysin AtlA and its process intermediates in cell wall degradation zymography, and 0.2 to 0.1 fold reduction of lytM, atlA, isaA, and walR transcripts in qRT-PCRs. Down-regulation of SprX resulted in altered phenotype with high cell aggregation as analyzed by SEM, decrease in biofilm formation and higher resistance to Triton X-100-induced lysis, all of which indicate that SprX is essential for expression of autolysins. A putative RNA-RNA interaction was indicated in silico between SprX and walR mRNA and further confirmed by in vitro RNA-RNA interaction in electrophoretic mobility shift assays. These findings elucidate a new mechanism in which SprX modulates the S. aureus pathogenicity by regulating the regulator of autolysins in cell wall metabolism and as virulence factors.
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Affiliation(s)
- Hasmatbanu Buchad
- Department of Microbiology and Biotechnology Centre, The Maharaja Sayajirao University of Baroda, Vadodara, Gujarat, 390002, India.
| | - Mrinalini Nair
- Department of Microbiology and Biotechnology Centre, The Maharaja Sayajirao University of Baroda, Vadodara, Gujarat, 390002, India.
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Longheu CM, Azara E, Marogna G, Addis MF, Tola S. Identification of secreted and cellular antigens of Staphylococcus aureus causing dairy sheep mastitis and their potential for vaccine development. Vet Immunol Immunopathol 2020; 230:110149. [PMID: 33197719 DOI: 10.1016/j.vetimm.2020.110149] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/26/2020] [Revised: 10/30/2020] [Accepted: 11/04/2020] [Indexed: 10/23/2022]
Abstract
Staphylococcus aureus is the leading cause of clinical mastitis and is associated with persistent subclinical infections in ewes, significantly compromising the quality and quantity of milk productions. To date, vaccines intended for use in sheep have been mainly focused on biofilm production traits, but many S. aureus pathogenic isolates do not produce biofilm, including those circulating in Sardinia, one of the leading sheep milk producers in Europe. The aim of this work was to identify suitable immunodominant, alternative candidates to biofilm components for vaccine and diagnostic development. An immunoproteomics study was carried out by testing sera from naturally infected sheep with a prevalent S. aureus lineage against cellular and secreted antigens, followed by tandem mass spectrometry identification of the most prominent immunogens. Four cellular and three secreted S. aureus antigens elicited a strong humoral host immune response. The four cellular antigens were the housekeeping proteins pyruvate kinase, elongation Factor Tu, dihydrolipoyl dehydrogenase, and alpha-keto acid dehydrogenase. The three secreted antigens were the bifunctional autolysin (Atl) and the two components of the Panton-Valentine leukocidin, lukF-PV/lukM, demonstrating the carriage of prophage phiPV83 in a sheep isolate and the strong response of the sheep host against them. In consideration of the key role played by these secreted proteins in S. aureus replication and immune evasion, these antigens may represent suitable candidates for developing vaccines eliciting a more successful immunological protection in areas where non-biofilm forming Staphylococcus spp. are the most widespread intramammary pathogens.
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Affiliation(s)
- Carla Maria Longheu
- Istituto Zooprofilattico Sperimentale della Sardegna"G. Pegreffi", Via Vienna 2, 07100, Sassari, Italy
| | - Elisa Azara
- Istituto Zooprofilattico Sperimentale della Sardegna"G. Pegreffi", Via Vienna 2, 07100, Sassari, Italy
| | - Gavino Marogna
- Istituto Zooprofilattico Sperimentale della Sardegna"G. Pegreffi", Via Vienna 2, 07100, Sassari, Italy
| | - Maria Filippa Addis
- Università degli Studi di Milano, Dipartimento di Medicina Veterinaria, Via dell'Università 6, Lodi, Italy
| | - Sebastiana Tola
- Istituto Zooprofilattico Sperimentale della Sardegna"G. Pegreffi", Via Vienna 2, 07100, Sassari, Italy.
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12
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Taheri-Anganeh M, Khatami SH, Jamali Z, Movahedpour A, Ghasemi Y, Savardashtaki A, Mostafavi-Pour Z. LytU-SH3b fusion protein as a novel and efficient enzybiotic against methicillin-resistant Staphylococcus aureus. Mol Biol Res Commun 2019; 8:151-158. [PMID: 32042832 PMCID: PMC6995334] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Indexed: 11/24/2022]
Abstract
Methicillin-resistant Staphylococcus aureus (MRSA) is a challenging infectious agent worldwide. The ever growing antibiotic resistance has made the researchers to look for new anti-staphylococcal agents. Autolysins are staphylococcal enzymes that lyse bacterial cell wall for cell division. Autolysins can be used as novel enzybiotics (enzymes have antibiotic effects) for staphylococcal infections. LytU is a newly explored autolysin. SH3b is a potent cell wall binding domain that can be fused to lytic enzymes to increase their activity. The aim of this study was to design a novel and efficient fusion enzybiotic that could lyse staphylococcal cell wall peptidoglycan by disrupting the bacteria. LytU-SH3b fusion construct was synthesized and LytU was amplified through the construct, using overhang PCR. The fusion and native forms that had his-tag were synthesized by recombinant technology in Escherichia coli BL21 (DE3) strain and purified utilizing Ni-NTA agarose beads. LytU and LytU-SH3b activity and potency were assessed using plate lysis assay, turbidity reduction assay and minimal inhibitory concentration (MIC) tests. All these tests showed that LytU-SH3b has more activity and potency than LytU. LytU-SH3b has MIC 421 fold lesser than LytU. Finally, LytU-SH3b is a novel and efficient recombinant enzybiotic that can lyse MRSA as an alternative to chemical small molecule antibiotics.
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Affiliation(s)
- Mortaza Taheri-Anganeh
- Department of Medical Biotechnology, School of Advanced Medical Sciences and Technologies, Shiraz University of Medical Sciences, Shiraz, Iran
| | - Seyyed Hossein Khatami
- Recombinant Protein Laboratory, Department of Biochemistry, School of Medicine, Shiraz University of Medical Sciences, Shiraz, Iran
| | - Zeinab Jamali
- Cardiovascular Research Center, Shiraz University of Medical Sciences, Shiraz, Iran
| | - Ahmad Movahedpour
- Department of Medical Biotechnology, School of Advanced Medical Sciences and Technologies, Shiraz University of Medical Sciences, Shiraz, Iran,Student Research Committee, Shiraz University of Medical Sciences, Shiraz, Iran
| | - Younes Ghasemi
- Department of Pharmaceutical Biotechnology, School of Pharmacy, Shiraz University of Medical Sciences, Shiraz, Iran,Pharmaceutical Sciences Research Center, Shiraz University of Medical Sciences, Shiraz, Iran
| | - Amir Savardashtaki
- Department of Medical Biotechnology, School of Advanced Medical Sciences and Technologies, Shiraz University of Medical Sciences, Shiraz, Iran,Pharmaceutical Sciences Research Center, Shiraz University of Medical Sciences, Shiraz, Iran
| | - Zohreh Mostafavi-Pour
- Recombinant Protein Laboratory, Department of Biochemistry, School of Medicine, Shiraz University of Medical Sciences, Shiraz, Iran,Maternal-Fetal Medicine Research Center, Shiraz University of Medical Sciences, Shiraz, Iran,Corresponding Author: Department of Biochemistry, Shiraz University of Medical Sciences, Shiraz, IR Iran. Tel: +98-713 2303029; Fax: +98-713 2303029
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13
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Matysik A, Ho FK, Ler Tan AQ, Vajjala A, Kline KA. Cellular chaining influences biofilm formation and structure in group A Streptococcus. Biofilm 2019; 2:100013. [PMID: 33447800 PMCID: PMC7798446 DOI: 10.1016/j.bioflm.2019.100013] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/31/2019] [Revised: 11/02/2019] [Accepted: 11/22/2019] [Indexed: 11/16/2022] Open
Abstract
Group A Streptococcal (GAS) biofilm formation is an important pathological feature contributing to the antibiotic tolerance and progression of various GAS infections. Although a number of bacterial factors have been described to promote in vitro GAS biofilm formation, the relevance of in vitro biofilms to host-associated biofilms requires further understanding. In this study, we demonstrate how constituents of the host environment, such as lysozyme and NaCl, can modulate GAS bacterial chain length and, in turn, shape GAS biofilm morphology and structure. Disruption of GAS chains with lysozyme results in biofilms that are more stable. Based on confocal microscopy, we attribute the increase in biofilm stability to a dense and compact three-dimensional structure produced by de-chained cells. To show that changes in biofilm stability and structure are due to the shortening of bacterial chains and not specific to the activity of lysozyme, we demonstrate that augmented chaining induced by NaCl or deletion of the autolysin gene mur1.2 produced defects in biofilm formation characterized by a loose biofilm architecture. We conclude that GAS biofilm formation can be directly influenced by host and environmental factors through the modulation of bacterial chain length, potentially contributing to persistence and colonization within the host. Further studies of in vitro biofilm models incorporating physiological constituents such as lysozyme may uncover new insights into the physiology of in vivo GAS biofilms.
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Affiliation(s)
- Artur Matysik
- Singapore Centre for Environmental Life Sciences Engineering, Nanyang Technological University, 60 Nanyang Dr, 637551, Singapore
| | - Foo Kiong Ho
- Singapore Centre for Environmental Life Sciences Engineering, Nanyang Technological University, 60 Nanyang Dr, 637551, Singapore
| | - Alicia Qian Ler Tan
- Singapore Centre for Environmental Life Sciences Engineering, Nanyang Technological University, 60 Nanyang Dr, 637551, Singapore
| | - Anuradha Vajjala
- Singapore Centre for Environmental Life Sciences Engineering, Nanyang Technological University, 60 Nanyang Dr, 637551, Singapore
| | - Kimberly A Kline
- Singapore Centre for Environmental Life Sciences Engineering, Nanyang Technological University, 60 Nanyang Dr, 637551, Singapore.,School of Biological Sciences, Nanyang Technological University, 60 Nanyang Dr, Singapore, 637551
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Zhang Y, Zhong X, Lu P, Zhu Y, Dong W, Roy S, Hejair HMA, Pan Z, Ma J, Yao H. A novel autolysin AtlA SS mediates bacterial cell separation during cell division and contributes to full virulence in Streptococcus suis. Vet Microbiol 2019; 234:92-100. [PMID: 31213278 DOI: 10.1016/j.vetmic.2019.05.020] [Citation(s) in RCA: 10] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/17/2019] [Accepted: 05/23/2019] [Indexed: 12/19/2022]
Abstract
Streptococcus suis (SS) is a major pathogen in the swine industry, and also an important zoonotic agent for humans. The novel SS cell surface protein, AtlASS, comprising the special GW module and N-acetylmuramidases domain, was designated as a putative autolysin. Indeed, the atlASS deletion mutant almost completely lost its activity in Triton X-100 induced bacterial autolysis, while the wild-type and CΔatlASS strains showed significant decrease, to less than 20% of the initial OD600 values. Unexpectedly, both immunofluorescence and immunogold electron microscopy confirmed that AtlASS is mainly located in the cell division septum, suggesting autolytic activity in peptidoglycan hydrolysis may be required for cell separation, thus modulating and truncating bacterial chain length. The biofilm capacity of the AtlASS mutation was reduced ˜ 40%, as compared to the wild-type strain. The ΔatlASS strain also attenuated bacterial adherence in human brain microvessel endothelial cells (HBMECs). Furthermore, we confirmed that AtlASS has fibrinogen/fibronectin binding capacities. In mouse infection model, the AtlASS inactivation also significantly attenuated bacterial virulence and proliferation in vivo. In conclusion, these results indicate that AtlASS autolysin modulates bacterial chain length, and contributes to the full virulence of SS during infection.
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15
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Kalali Y, Haghighat S, Mahdavi M. Passive immunotherapy with specific IgG fraction against autolysin: Analogous protectivity in the MRSA infection with antibiotic therapy. Immunol Lett 2018; 212:125-131. [PMID: 30496765 DOI: 10.1016/j.imlet.2018.11.010] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/08/2018] [Revised: 11/20/2018] [Accepted: 11/25/2018] [Indexed: 11/16/2022]
Abstract
Staphylococcus aureus is a leading infectious cause of life-threatening diseases in human beings, with no effective vaccine available to date against this bacterium. Treatment of methicillin-resistant S. aureus (MRSA) infections has become increasingly difficult because of the emergence of multidrug-resistant isolates. Immunotherapy represents a potential approach to prevent S. aureus-related infections. Autolysin is one of the virulence factors, which controls the growth, cell lysis, daughter-cell separation, and biofilm formation. Our study focused on passive immunization against MRSA infection. Herein, rabbit polyclonal IgG was produced following the preparation of r-autolysin. Specificity of IgG against r-autolysin was investigated by ELISA and western blotting assays. IgG fraction was prepared using sulfate ammonium precipitation, and the ability of antiserum to promote phagocytosis of bacteria was assessed by opsonophagocytosis assay. Then, passive immunization of mice was carried out with polyclonal IgG fraction and, mice were sacrificed three days after challenge and their kidneys, liver, and spleen were collected. Results exhibited that the passive immunization with rabbit polyclonal anti-IgG fraction tremendously improved survival rates of mice challenged by S. aureus as well as vancomycin treatment compared with the negative control groups. In addition, a remarkable decrease in bacterial numbers was observed in mice treated with rabbit polyclonal anti-IgG. Importantly, our findings demonstrated that passive immunotherapy and antibiotic therapy lead to decreased histopathological damage in mice infected by S. aureus as compared with control groups. Our results suggested that the passive immunization may result in the introduction of excellent strategies to control infections caused by MRSA, like antibiotic therapy.
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Affiliation(s)
- Yasamin Kalali
- Department of Biotechnology, Faculty of Advanced Science and Technology, Tehran Medical Sciences, Islamic Azad University, Tehran, Iran
| | - Setareh Haghighat
- Department of Microbiology, Faculty of Advanced Science and Technology, Tehran Medical Sciences, Islamic Azad University, Tehran, Iran.
| | - Mehdi Mahdavi
- Recombinant Vaccine Research Center, Tehran University of Medical Sciences, Tehran, Iran
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16
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Porayath C, Suresh MK, Biswas R, Nair BG, Mishra N, Pal S. Autolysin mediated adherence of Staphylococcus aureus with Fibronectin, Gelatin and Heparin. Int J Biol Macromol 2018; 110:179-184. [PMID: 29398086 PMCID: PMC5864509 DOI: 10.1016/j.ijbiomac.2018.01.047] [Citation(s) in RCA: 33] [Impact Index Per Article: 5.5] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/15/2017] [Revised: 12/20/2017] [Accepted: 01/08/2018] [Indexed: 12/21/2022]
Abstract
Major autolysin (Atl) of Staphylococcus aureusis a cell surface associated peptidoglycan hydrolase with amidase and glucosaminidase domains. Atl enzymes (amidase and glucosaminidase) are known to participate in biofilm formation and also can bind with host matrices. Earlier studies demonstrated the binding of Atlwithfibronectin, thrombospondin 1, vitronectin and heat shock cognate protein Hsc70. Here, we have shown, Atl mediates attachment of S.aureus to heparin and gelatine as well. The atl mutant strain demonstrated around 2.5 fold decreased adherence with fibronectin, gelatin and heparin coated microtiter plates. The microscopic studies confirmed the reduced binding of atl mutant with them compared to its parental wild type and complemented mutant strains. Amidase and glucosaminidase were expressed as N-terminal histidine tagged proteins from Escherichia coli, purified and refolded. We found refolded amidase bind with fibronectin, gelatin and heparin; whereas refolded glucosaminidase binds with only fibronectin and heparin but not gelatin. These results reemphasize Atl as one of the crucial proteins from Staphylococcus that facilitate their binding with multiple host cellular components during colonization and infection.
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Affiliation(s)
- Chandni Porayath
- School of Biotechnology, Amrita Vishwa Vidyapeetham, Kollam 690525, Kerala, India
| | - Maneesha K Suresh
- Centre for Nanosciences and Molecular Medicine, Amrita Institute of Medical Sciences, Amrita Vishwa Vidyapeetham, Cochin 682041, Kerala, India
| | - Raja Biswas
- Centre for Nanosciences and Molecular Medicine, Amrita Institute of Medical Sciences, Amrita Vishwa Vidyapeetham, Cochin 682041, Kerala, India
| | - Bipin G Nair
- School of Biotechnology, Amrita Vishwa Vidyapeetham, Kollam 690525, Kerala, India
| | - Nandita Mishra
- School of Biotechnology, Amrita Vishwa Vidyapeetham, Kollam 690525, Kerala, India
| | - Sanjay Pal
- School of Biotechnology, Amrita Vishwa Vidyapeetham, Kollam 690525, Kerala, India.
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17
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Haghighat S, Siadat SD, Sorkhabadi SMR, Sepahi AA, Mahdavi M. Cloning, expression and purification of autolysin from methicillin-resistant Staphylococcus aureus: potency and challenge study in Balb/c mice. Mol Immunol 2016; 82:10-18. [PMID: 28006655 DOI: 10.1016/j.molimm.2016.12.013] [Citation(s) in RCA: 13] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/27/2016] [Revised: 12/09/2016] [Accepted: 12/12/2016] [Indexed: 10/20/2022]
Abstract
Staphylococcus aureus (MRSA) is an opportunistic pathogen which causes a variety of clinical diseases and leads to high rates of morbidity and mortality. Development of an effective vaccine appears to be a useful strategy to control the infection. Here, the internal region of atl was cloned into the pET24a plasmid and expressed in E. coli BL21 (DE3). Cloning of atl was confirmed by colony-PCR, enzymatic digestion and sequencing. Protein expressed in E coli, BL21 DE3 and was confirmed with SDS-PAGE and western blot analysis. Subsequently, BALB/c mice were injected subcutaneously three times with 20μg of the recombinant autolysin. After Bleeding, autolysin-specific total IgG antibodies and isotypes were evaluated using ELISA. Opsonophagocytic killing assay was performed and experimental challenge was done by intraperitoneal injection with sub lethal doses of MRSA in mice and also survival rate was regularly monitored. Results showed that vaccinated mice could exhibit higher levels of autolysin-specific antibodies (P<0.0001) with a predominant IgG1 response versus control group. Results from in vitro experiments indicated that S. aureus opsonized with immunized-mice sera displayed significantly increased phagocytic uptake and effective intracellular killing versus non-immunized mice. The number of viable bacteria in the kidney of immunized mice showed 1000 times less than the control mice; additionally, an increased survival rate was found after immunization with the candidate vaccine versus control group. Results from this study demonstrated that the autolysin is a valuable target for the development of immunotherapeutic strategies against S. aureus and candidate vaccines.
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Affiliation(s)
- Setareh Haghighat
- Department of Microbiology, Faculty of Advanced Sciences and Technology, Pharmaceutical Sciences Branch, Islamic Azad University (IAUPS), Tehran, Iran.
| | - Seyed Davar Siadat
- Department of Mycobacteriology & Pulmonary Research, Microbiology Research center, Pasteur Institute of Iran, Tehran, Iran.
| | - Seyed Mehdi Rezayat Sorkhabadi
- Department of Pharmacology & Toxicology, Faculty of Pharmacy, Pharmaceutical Sciences Branch, Islamic Azad University (IAUPS), Tehran, Iran
| | - Abbas Akhavan Sepahi
- Department of Microbiology, Faculty of Basic Sciences, North Tehran Branch, Islamic Azad University, Tehran, Iran
| | - Mehdi Mahdavi
- Department of Immunology, Pasteur Institute of Iran, Tehran, Iran
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McCarthy H, Waters EM, Bose JL, Foster S, Bayles KW, O'Neill E, Fey PD, O'Gara JP. The major autolysin is redundant for Staphylococcus aureus USA300 LAC JE2 virulence in a murine device-related infection model. FEMS Microbiol Lett 2016; 363:fnw087. [PMID: 27044299 DOI: 10.1093/femsle/fnw087] [Citation(s) in RCA: 14] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Accepted: 03/31/2016] [Indexed: 12/14/2022] Open
Abstract
The major Staphylococcus aureus autolysin, Atl, has been implicated in attachment to surfaces and release of extracellular DNA during biofilm formation under laboratory conditions. Consistent with this, polyclonal antibodies to the amidase and glucosaminidase domains of Atl inhibited in vitro biofilm formation. However, in a murine model of device-related infection the community-associated S. aureus strain USA300 LAC JE2 established a successful infection in the absence of atl These data indicate that Atl activity is not required for biofilm production in this infection model and reveal the importance of characterizing the contribution of biofilm phenotypes to virulence under in vivo conditions.
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Affiliation(s)
- Hannah McCarthy
- Department of Microbiology, School of Natural Sciences, National University of Ireland, Galway, Ireland
| | - Elaine M Waters
- Department of Pathology and Microbiology, Center for Staphylococcal Research, University of Nebraska Medical Center, Omaha, NE 68198-5900, USA
| | - Jeffrey L Bose
- Department of Pathology and Microbiology, Center for Staphylococcal Research, University of Nebraska Medical Center, Omaha, NE 68198-5900, USA
| | - Simon Foster
- Department of Molecular Biology and Biotechnology, The Krebs Institute, University of Sheffield, Sheffield S10 2TN, UK
| | - Kenneth W Bayles
- Department of Pathology and Microbiology, Center for Staphylococcal Research, University of Nebraska Medical Center, Omaha, NE 68198-5900, USA
| | - Eoghan O'Neill
- Department of Clinical Microbiology, Royal College of Surgeons in Ireland, Connolly Hospital, Dublin 15, Ireland
| | - Paul D Fey
- Department of Pathology and Microbiology, Center for Staphylococcal Research, University of Nebraska Medical Center, Omaha, NE 68198-5900, USA
| | - James P O'Gara
- Department of Microbiology, School of Natural Sciences, National University of Ireland, Galway, Ireland
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Lioliou E, Fechter P, Caldelari I, Jester BC, Dubrac S, Helfer AC, Boisset S, Vandenesch F, Romby P, Geissmann T. Various checkpoints prevent the synthesis of Staphylococcus aureus peptidoglycan hydrolase LytM in the stationary growth phase. RNA Biol 2016; 13:427-40. [PMID: 26901414 DOI: 10.1080/15476286.2016.1153209] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/21/2023] Open
Abstract
In Staphylococcus aureus, peptidoglycan metabolism plays a role in the host inflammatory response and pathogenesis. Transcription of the peptidoglycan hydrolases is activated by the essential 2-component system WalKR at low cell density. During stationary growth phase, WalKR is not active and transcription of the peptidoglycan hydrolase genes is repressed. In this work, we studied regulation of expression of the glycylglycine endopeptidase LytM. We show that, in addition to the transcriptional regulation mediated by WalKR, the synthesis of LytM is negatively controlled by a unique mechanism at the stationary growth phase. We have identified 2 different mRNAs encoding lytM, which vary in the length of their 5' untranslated (5'UTR) regions. LytM is predominantly produced from the WalKR-regulated mRNA transcript carrying a short 5'UTR. The lytM mRNA is also transcribed as part of a polycistronic operon with the upstream SA0264 gene and is constitutively expressed. Although SA0264 protein can be synthesized from the longer operon transcript, lytM cannot be translated because its ribosome-binding site is sequestered into a translationally inactive secondary structure. In addition, the effector of the agr system, RNAIII, can inhibit translation of lytM present on the operon without altering the transcript level but does not have an effect on the translation of the upstream gene. We propose that this dual regulation of lytM expression, at the transcriptional and post-transcriptional levels, contributes to prevent cell wall damage during the stationary phase of growth.
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Affiliation(s)
- Efthimia Lioliou
- a Architecture et Réactivité de l'ARN, Université de Strasbourg, CNRS, IBMC , 15 rue René Descartes, Strasbourg , France
| | - Pierre Fechter
- a Architecture et Réactivité de l'ARN, Université de Strasbourg, CNRS, IBMC , 15 rue René Descartes, Strasbourg , France
| | - Isabelle Caldelari
- a Architecture et Réactivité de l'ARN, Université de Strasbourg, CNRS, IBMC , 15 rue René Descartes, Strasbourg , France
| | - Brian C Jester
- b Institute of Systems and Synthetic Biology, University of Evry-Val-d'Essonne, CNRS FRE3561 , Evry , France
| | - Sarah Dubrac
- c Unité de Biologie des Bactéries pathogènes à Gram-positif, Institut Pasteur , 28 rue du Dr Roux, Paris , France
| | - Anne-Catherine Helfer
- a Architecture et Réactivité de l'ARN, Université de Strasbourg, CNRS, IBMC , 15 rue René Descartes, Strasbourg , France
| | - Sandrine Boisset
- d CIRI, Center International de Recherche en Infectiologie - Inserm U1111 - Université Lyon 1 - Ecole Normale Supérieure de Lyon - CNRS UMR5308 , 21 Avenue Tony Garnier, LYON cedex 07 , France
| | - François Vandenesch
- d CIRI, Center International de Recherche en Infectiologie - Inserm U1111 - Université Lyon 1 - Ecole Normale Supérieure de Lyon - CNRS UMR5308 , 21 Avenue Tony Garnier, LYON cedex 07 , France
| | - Pascale Romby
- a Architecture et Réactivité de l'ARN, Université de Strasbourg, CNRS, IBMC , 15 rue René Descartes, Strasbourg , France
| | - Thomas Geissmann
- d CIRI, Center International de Recherche en Infectiologie - Inserm U1111 - Université Lyon 1 - Ecole Normale Supérieure de Lyon - CNRS UMR5308 , 21 Avenue Tony Garnier, LYON cedex 07 , France
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Dehbashi S, Pourmand MR, Mashhadi R. Characterization of Afb, a novel bifunctional protein in Streptococcus agalactiae. Iran J Microbiol 2016; 8:73-9. [PMID: 27092228 PMCID: PMC4833744] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Indexed: 12/02/2022]
Abstract
BACKGROUND AND OBJECTIVES Streptococcus agalactiae is the leading cause of bacterial sepsis and meningitis in newborns and results in pneumonia and bacteremia in adults. A number of S. agalactiae components are involved in colonization of target cells. Destruction of peptidoglycan and division of covalently linked daughter cells is mediated by autolysins. In this study, autolytic activity and plasma binding ability of AFb novel recombinant protein of S. agalactiae was investigated. MATERIALS AND METHODS The gbs1805 gene was cloned and expressed. E. coli strains DH5α and BL21 were used as cloning and expression hosts, respectively. After purification, antigenicity and binding ability to plasma proteins of the recombinant protein was evaluated. RESULTS AFb, the 18KDa protein was purified successfully. The insoluble mature protein revealed the ability to bind to fibrinogen and fibronectin. This insoluble mature protein revealed that it has the ability to bind to fibrinogen and fibronectin plasma proteins. Furthermore, in silico analysis demonstrated the AFb has an autolytic activity. CONCLUSIONS AFb is a novel protein capable of binding to fibrinogen and fibronectin. This findings lay a ground work for further investigation of the role of the bacteria in adhesion and colonization to the host.
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Affiliation(s)
- Sanaz Dehbashi
- Department of Pathobiology, School of Public Health, Tehran University of Medical Sciences, Tehran, Iran
| | - Mohammad Reza Pourmand
- Urology Research Center, Tehran University of Medical Sciences, Tehran, Iran,Corresponding author: Mohammad Reza Pourmand Address: Department of Pathobiology, School of Public Health and Biotechnology Research Center, Tehran University of Medical Sciences, Tehran, Iran. Tel: +98-21- 88954910, E-mail:
| | - Rahil Mashhadi
- Urology Research Center, Tehran University of Medical Sciences, Tehran, Iran
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Hussain M, Steinbacher T, Peters G, Heilmann C, Becker K. The adhesive properties of the Staphylococcus lugdunensis multifunctional autolysin AtlL and its role in biofilm formation and internalization. Int J Med Microbiol 2015; 305:129-39. [PMID: 25515664 DOI: 10.1016/j.ijmm.2014.11.010] [Citation(s) in RCA: 32] [Impact Index Per Article: 3.2] [Reference Citation Analysis] [What about the content of this article? (0)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/04/2014] [Revised: 11/18/2014] [Accepted: 11/23/2014] [Indexed: 10/24/2022] Open
Abstract
Although it belongs to the group of coagulase-negative staphylococci, Staphylococcus lugdunensis has been known to cause aggressive courses of native and prosthetic valve infective endocarditis with high mortality similar to Staphylococcus aureus. In contrast to S. aureus, only little is known about the equipment of S. lugdunensis with virulence factors including adhesins and their role in mediating attachment to extracellular matrix and plasma proteins and host cells. In this study, we show that the multifunctional autolysin/adhesin AtlL of S. lugdunensis binds to the extracellular matrix and plasma proteins fibronectin, fibrinogen, and vitronectin as well as to human EA.hy926 endothelial cells. Furthermore, we demonstrate that AtlL also plays an important role in the internalization of S. lugdunensis by eukaryotic cells: The atlL-deficient mutant Mut17 adheres to and becomes internalized by eukaryotic cells to a lesser extent than the isogenic wild-type strain Sl253 and the complemented mutant Mut17 (pCUatlL) shows an increased internalization level in comparison to Mut17. Thus, surface localized AtlL that exhibits a broad binding spectrum also mediates the internalization of S. lugdunensis by eukaryotic cells. We therefore propose an internalization pathway for S. lugdunensis, in which AtlL plays a major role. Investigating the role of AtlL in biofilm formation of S. lugdunensis, Mut17 shows a significantly reduced ability for biofilm formation, which is restored in the complemented mutant. Thus, our data provide evidence for a significant role for AtlL in adherence and internalization processes as well as in biofilm formation of S. lugdunensis.
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Herlihey FA, Moynihan PJ, Clarke AJ. The essential protein for bacterial flagella formation FlgJ functions as a β-N-acetylglucosaminidase. J Biol Chem 2014; 289:31029-42. [PMID: 25248745 DOI: 10.1074/jbc.m114.603944] [Citation(s) in RCA: 45] [Impact Index Per Article: 4.5] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/06/2022] Open
Abstract
The flagellum is a major virulence factor of motile pathogenic bacteria. This structure requires more than 50 proteins for its biogenesis and function, one of which is FlgJ. Homologs of FlgJ produced by the β- and γ-proteobacteria, such as Salmonella enterica, Vibrio spp., and both Sphingomonas sp. and Pseudomonas spp. are bifunctional, possessing an N-terminal domain responsible for proper rod assembly and a C-terminal domain possessing peptidoglycan lytic activity. Despite the amount of research conducted on FlgJ from these and other bacteria over the past 15 years, no biochemical analysis had been conducted on any FlgJ and consequently confusion exists as to whether the enzyme is a peptidoglycan hydrolase or a lytic transglycosylase. In this study, we present the development of a novel assay for glycoside lytic enzymes and its use to provide the first enzymatic characterization of the lytic domain of FlgJ from S. enterica as the model enzyme. Surprisingly, FlgJ functions as neither a muramidase nor a lytic transglycosylases but rather as a β-N-acetylglucosaminidase. As such, FlgJ represents the first autolysin with this activity to be characterized from a Gram-negative bacterium. At its optimal pH of 4.0, the Michaelis-Menten parameters of K(m) and k(cat) for FlgJ from S. enterica were determined to be 0.64 ± 0.18 mg ml(-1) and 0.13 ± 0.016 s(-1), respectively, using purified PG as substrate. Its catalytic residues were identified as Glu(184) and Glu(223).
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Affiliation(s)
- Francesca A Herlihey
- From the Department of Molecular and Cellular Biology, University of Guelph, Guelph, Ontario N1G 2W1, Canada
| | - Patrick J Moynihan
- From the Department of Molecular and Cellular Biology, University of Guelph, Guelph, Ontario N1G 2W1, Canada
| | - Anthony J Clarke
- From the Department of Molecular and Cellular Biology, University of Guelph, Guelph, Ontario N1G 2W1, Canada
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Büttner FM, Zoll S, Nega M, Götz F, Stehle T. Structure-function analysis of Staphylococcus aureus amidase reveals the determinants of peptidoglycan recognition and cleavage. J Biol Chem 2014; 289:11083-11094. [PMID: 24599952 DOI: 10.1074/jbc.m114.557306] [Citation(s) in RCA: 32] [Impact Index Per Article: 3.2] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/06/2022] Open
Abstract
The bifunctional major autolysin AtlA of Staphylococcus aureus cleaves the bacterium's peptidoglycan network (PGN) at two distinct sites during cell division. Deletion of the enzyme results in large cell clusters with disordered division patterns, indicating that AtlA could be a promising target for the development of new antibiotics. One of the two functions of AtlA is performed by the N-acetylmuramyl-l-alanine amidase AmiA, which cleaves the bond between the carbohydrate and the peptide moieties of PGN. To establish the structural requirements of PGN recognition and the enzymatic mechanism of cleavage, we solved the crystal structure of the catalytic domain of AmiA (AmiA-cat) in complex with a peptidoglycan-derived ligand at 1.55 Å resolution. The peptide stem is clearly visible in the structure, forming extensive contacts with protein residues by docking into an elongated groove. Less well defined electron density and the analysis of surface features indicate likely positions of the carbohydrate backbone and the pentaglycine bridge. Substrate specificity analysis supports the importance of the pentaglycine bridge for fitting into the binding cleft of AmiA-cat. PGN of S. aureus with l-lysine tethered with d-alanine via a pentaglycine bridge is completely hydrolyzed, whereas PGN of Bacillus subtilis with meso-diaminopimelic acid directly tethered with d-alanine is not hydrolyzed. An active site mutant, H370A, of AmiA-cat was completely inactive, providing further support for the proposed catalytic mechanism of AmiA. The structure reported here is not only the first of any bacterial amidase in which both the PGN component and the water molecule that carries out the nucleophilic attack on the carbonyl carbon of the scissile bond are present; it is also the first peptidoglycan amidase complex structure of an important human pathogen.
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Affiliation(s)
- Felix Michael Büttner
- Interfaculty Institute of Biochemistry, University of Tübingen, Hoppe-Seyler-Strasse 4, 72076 Tübingen, Germany
| | - Sebastian Zoll
- Interfaculty Institute of Biochemistry, University of Tübingen, Hoppe-Seyler-Strasse 4, 72076 Tübingen, Germany
| | - Mulugeta Nega
- Microbial Genetics, Interfaculty Institute of Microbiology and Infection Medicine, University of Tübingen, Auf der Morgenstelle 28, 72076 Tübingen, Germany, and
| | - Friedrich Götz
- Microbial Genetics, Interfaculty Institute of Microbiology and Infection Medicine, University of Tübingen, Auf der Morgenstelle 28, 72076 Tübingen, Germany, and
| | - Thilo Stehle
- Interfaculty Institute of Biochemistry, University of Tübingen, Hoppe-Seyler-Strasse 4, 72076 Tübingen, Germany,; Department of Pediatrics, Vanderbilt University School of Medicine, Nashville, Tennessee 37232.
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Kohler TP, Gisch N, Binsker U, Schlag M, Darm K, Völker U, Zähringer U, Hammerschmidt S. Repeating structures of the major staphylococcal autolysin are essential for the interaction with human thrombospondin 1 and vitronectin. J Biol Chem 2013; 289:4070-82. [PMID: 24371140 DOI: 10.1074/jbc.m113.521229] [Citation(s) in RCA: 22] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/10/2023] Open
Abstract
Human thrombospondin 1 (hTSP-1) is a matricellular glycoprotein facilitating bacterial adherence to and invasion into eukaryotic cells. However, the bacterial adhesin(s) remain elusive. In this study, we show a dose-dependent binding of soluble hTSP-1 to Gram-positive but not Gram-negative bacteria. Diminished binding of soluble hTSP-1 to proteolytically pretreated staphylococci suggested a proteinaceous nature of potential bacterial adhesin(s) for hTSP-1. A combination of separation of staphylococcal surface proteins by two-dimensional gel electrophoresis with a ligand overlay assay with hTSP-1 and identification of the target protein by mass spectrometry revealed the major staphylococcal autolysin Atl as a bacterial binding protein for hTSP-1. Binding experiments with heterologously expressed repeats of the AtlE amidase from Staphylococcus epidermidis suggest that the repeating sequences (R1ab-R2ab) of the N-acetyl-muramoyl-L-alanine amidase of Atl are essential for binding of hTSP-1. Atl has also been identified previously as a staphylococcal vitronectin (Vn)-binding protein. Similar to the interaction with hTSP-1, the R1ab-R2ab repeats of Atl are shown here to be crucial for the interaction of Atl with the complement inhibition and matrix protein Vn. Competition assays with hTSP-1 and Vn revealed the R1ab-R2ab repeats of AtlE as the common binding domain for both host proteins. Furthermore, Vn competes with hTSP-1 for binding to Atl repeats and vice versa. In conclusion, this study identifies the Atl repeats as bacterial adhesive structures interacting with the human glycoproteins hTSP-1 and Vn. Finally, this study provides insight into the molecular interplay between hTSP-1 and Vn, respectively, and a bacterial autolysin.
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Reddy BL, Saier MH. Topological and phylogenetic analyses of bacterial holin families and superfamilies. Biochim Biophys Acta 2013; 1828:2654-71. [PMID: 23856191 DOI: 10.1016/j.bbamem.2013.07.004] [Citation(s) in RCA: 49] [Impact Index Per Article: 4.5] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 05/04/2013] [Revised: 06/28/2013] [Accepted: 07/02/2013] [Indexed: 01/21/2023]
Abstract
Holins are small "hole-forming" transmembrane proteins that mediate bacterial cell lysis during programmed cell death or following phage infection. We have identified fifty two families of established or putative holins and have included representative members of these proteins in the Transporter Classification Database (TCDB; www.tcdb.org). We have identified the organismal sources of members of these families, calculated their average protein sizes, estimated their topologies and determined their relative family sizes. Topological analyses suggest that these proteins can have 1, 2, 3 or 4 transmembrane α-helical segments (TMSs), and members of a single family are frequently, but not always, of a single topology. In one case, proteins of a family proved to have either 2 or 4 TMSs, and the latter arose by intragenic duplication of a primordial 2 TMS protein-encoding gene resembling the former. Using established statistical approaches, some of these families have been shown to be related by common descent. Seven superfamilies, including 21 of the 52 recognized families were identified. Conserved motif and Pfam analyses confirmed most superfamily assignments. These results serve to expand upon the scope of channel-forming bacterial holins.
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Affiliation(s)
- Bhaskara L Reddy
- Department of Molecular Biology, Division of Biological Sciences, University of California at San Diego, La Jolla, CA 92093-0116, USA; Department of Mathematics and Natural Sciences, College of Letters and Sciences, National University, Ontario, CA 91764, USA
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Rolain T, Bernard E, Beaussart A, Degand H, Courtin P, Egge-Jacobsen W, Bron PA, Morsomme P, Kleerebezem M, Chapot-Chartier MP, Dufrêne YF, Hols P. O-glycosylation as a novel control mechanism of peptidoglycan hydrolase activity. J Biol Chem 2013; 288:22233-47. [PMID: 23760506 DOI: 10.1074/jbc.m113.470716] [Citation(s) in RCA: 33] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/06/2022] Open
Abstract
Acm2, the major autolysin of Lactobacillus plantarum, is a tripartite protein. Its catalytic domain is surrounded by an O-glycosylated N-terminal region rich in Ala, Ser, and Thr (AST domain), which is of low complexity and unknown function, and a C-terminal region composed of five SH3b peptidoglycan (PG) binding domains. Here, we investigate the contribution of these two accessory domains and of O-glycosylation to Acm2 functionality. We demonstrate that Acm2 is an N-acetylglucosaminidase and identify the pattern of O-glycosylation (21 mono-N-acetylglucosamines) of its AST domain. The O-glycosylation process is species-specific as Acm2 purified from Lactococcus lactis is not glycosylated. We therefore explored the functional role of O-glycosylation by purifying different truncated versions of Acm2 that were either glycosylated or non-glycosylated. We show that SH3b domains are able to bind PG and are responsible for Acm2 targeting to the septum of dividing cells, whereas the AST domain and its O-glycosylation are not involved in this process. Notably, our data reveal that the lack of O-glycosylation of the AST domain significantly increases Acm2 enzymatic activity, whereas removal of SH3b PG binding domains dramatically reduces this activity. Based on this antagonistic role, we propose a model in which access of the Acm2 catalytic domain to its substrate may be hindered by the AST domain where O-glycosylation changes its conformation and/or mediates interdomain interactions. To the best of our knowledge, this is the first time that O-glycosylation is shown to control the activity of a bacterial enzyme.
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Affiliation(s)
- Thomas Rolain
- Institut des Sciences de la Vie, Université catholique de Louvain, B-1348 Louvain-la-Neuve, Belgium
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Abstract
Disulfide bonds are important for the stability of many extracellular proteins, including bacterial virulence factors. Formation of these bonds is catalyzed by thiol-disulfide oxidoreductases (TDORs). Little is known about their formation in Gram-positive bacteria, particularly among facultative anaerobic Firmicutes, such as streptococci. To investigate disulfide bond formation in Streptococcus gordonii, we identified five putative TDORs from the sequenced genome. Each of the putative TDOR genes was insertionally inactivated with an erythromycin resistance cassette, and the mutants were analyzed for autolysis, extracellular DNA release, biofilm formation, bacteriocin production, and genetic competence. This analysis revealed a single TDOR, SdbA, which exhibited a pleiotropic mutant phenotype. Using an in silico analysis approach, we identified the major autolysin AtlS as a natural substrate of SdbA and showed that SdbA is critical to the formation of a disulfide bond that is required for autolytic activity. Analysis by BLAST search revealed homologs to SdbA in other Gram-positive species. This study provides the first in vivo evidence of an oxidoreductase, SdbA, that affects multiple phenotypes in a Gram-positive bacterium. SdbA shows low sequence homology to previously identified oxidoreductases, suggesting that it may belong to a different class of enzymes. Our results demonstrate that SdbA is required for disulfide bond formation in S. gordonii and indicate that this enzyme may represent a novel type of oxidoreductase in Gram-positive bacteria.
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Affiliation(s)
- Lauren Davey
- Department of Microbiology and Immunology, Dalhousie University, Halifax, Nova Scotia B3H 1X5, Canada; Canadian Center for Vaccinology, Dalhousie University and the Izaak Walton Killam Health Centre, Halifax, Nova Scotia B3K 6R8, Canada
| | - Crystal K W Ng
- Department of Microbiology and Immunology, Dalhousie University, Halifax, Nova Scotia B3H 1X5, Canada; Canadian Center for Vaccinology, Dalhousie University and the Izaak Walton Killam Health Centre, Halifax, Nova Scotia B3K 6R8, Canada
| | - Scott A Halperin
- Department of Microbiology and Immunology, Dalhousie University, Halifax, Nova Scotia B3H 1X5, Canada; Canadian Center for Vaccinology, Dalhousie University and the Izaak Walton Killam Health Centre, Halifax, Nova Scotia B3K 6R8, Canada; Department of Pediatrics, Faculty of Medicine, Dalhousie University and the Izaak Walton Killam Health Centre, Halifax, Nova Scotia B3K 6R8, Canada
| | - Song F Lee
- Department of Microbiology and Immunology, Dalhousie University, Halifax, Nova Scotia B3H 1X5, Canada; Canadian Center for Vaccinology, Dalhousie University and the Izaak Walton Killam Health Centre, Halifax, Nova Scotia B3K 6R8, Canada; Department of Pediatrics, Faculty of Medicine, Dalhousie University and the Izaak Walton Killam Health Centre, Halifax, Nova Scotia B3K 6R8, Canada; Department of Applied Oral Sciences, Faculty of Dentistry, Dalhousie University, Halifax, Nova Scotia B3H 4R2, Canada.
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