1
|
Vander Elst N. Bacteriophage-derived endolysins as innovative antimicrobials against bovine mastitis-causing streptococci and staphylococci: a state-of-the-art review. Acta Vet Scand 2024; 66:20. [PMID: 38769566 PMCID: PMC11106882 DOI: 10.1186/s13028-024-00740-2] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/06/2024] [Accepted: 04/05/2024] [Indexed: 05/22/2024] Open
Abstract
Bacteriophage-encoded endolysins, peptidoglycan hydrolases breaking down the Gram-positive bacterial cell wall, represent a groundbreaking class of novel antimicrobials to revolutionize the veterinary medicine field. Wild-type endolysins exhibit a modular structure, consisting of enzymatically active and cell wall-binding domains, that enable genetic engineering strategies for the creation of chimeric fusion proteins or so-called 'engineered endolysins'. This biotechnological approach has yielded variants with modified lytic spectrums, introducing new possibilities in antimicrobial development. However, the discovery of highly similar endolysins by different groups has occasionally resulted in the assignment of different names that complicate a straightforward comparison. The aim of this review was to perform a homology-based comparison of the wild-type and engineered endolysins that have been characterized in the context of bovine mastitis-causing streptococci and staphylococci, grouping homologous endolysins with ≥ 95.0% protein sequence similarity. Literature is explored by homologous groups for the wild-type endolysins, followed by a chronological examination of engineered endolysins according to their year of publication. This review concludes that the wild-type endolysins encountered persistent challenges in raw milk and in vivo settings, causing a notable shift in the field towards the engineering of endolysins. Lead candidates that display robust lytic activity are nowadays selected from screening assays that are performed under these challenging conditions, often utilizing advanced high-throughput protein engineering methods. Overall, these recent advancements suggest that endolysins will integrate into the antibiotic arsenal over the next decade, thereby innovating antimicrobial treatment against bovine mastitis-causing streptococci and staphylococci.
Collapse
Affiliation(s)
- Niels Vander Elst
- Department of Neuroscience, Karolinska Institutet, Biomedicum 7D, Solnavägen 9, 17165, Solna, Stockholm, Sweden.
| |
Collapse
|
2
|
Vázquez R, Briers Y. What's in a Name? An Overview of the Proliferating Nomenclature in the Field of Phage Lysins. Cells 2023; 12:2016. [PMID: 37566095 PMCID: PMC10417350 DOI: 10.3390/cells12152016] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/06/2023] [Revised: 08/02/2023] [Accepted: 08/04/2023] [Indexed: 08/12/2023] Open
Abstract
In the last few years, the volume of research produced on phage lysins has grown spectacularly due to the interest in using them as alternative antimicrobials. As a result, a plethora of naming customs has sprouted among the different research groups devoted to them. While the naming diversity accounts for the vitality of the topic, on too many occasions it also creates some confusion and lack of comparability between different works. This article aims at clarifying the ambiguities found among names referring to phage lysins. We do so by tackling the naming customs historically, framing their original adoption, and employing a semantic classification to facilitate their discussion. We propose a periodization of phage lysin research that begins at the discovery era, in the early 20th century, enriches with a strong molecular biology period, and grows into a current time of markedly applied research. During these different periods, names referring to the general concepts surrounding lysins have been created and adopted, as well as other more specific terms related to their structure and function or, finally, names that have been coined for the antimicrobial application and engineering of phage lysins. Thus, this article means to serve as an invitation to the global lysin community to take action and discuss a widely supported, standardized nomenclature.
Collapse
Affiliation(s)
- Roberto Vázquez
- Laboratory of Applied Biotechnology, Department of Biotechnology, Ghent University, 9000 Ghent, Belgium
| | - Yves Briers
- Laboratory of Applied Biotechnology, Department of Biotechnology, Ghent University, 9000 Ghent, Belgium
| |
Collapse
|
3
|
Duan XC, Li XX, Li XM, Wang S, Zhang FQ, Qian P. Exploiting Broad-Spectrum Chimeric Lysin to Cooperate with Mupirocin against Staphylococcus aureus-Induced Skin Infections and Delay the Development of Mupirocin Resistance. Microbiol Spectr 2023; 11:e0505022. [PMID: 37125939 PMCID: PMC10269905 DOI: 10.1128/spectrum.05050-22] [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: 12/08/2022] [Accepted: 04/10/2023] [Indexed: 05/02/2023] Open
Abstract
Staphylococcus aureus often leads to severe skin infections. However, S. aureus is facing a crisis of antibiotic resistance. The combination of phage and antibiotics is effective for drug-resistant S. aureus infections. Therefore, it is worth exploiting novel antibacterial agents to cooperate with antibiotics against S. aureus infections. Herein, a novel chimeric lysin ClyQ was constructed, which was composed of a cysteine- and histidine-dependent amidohydrolase/peptidase (CHAP) catalytic domain from S. aureus phage lysin LysGH15 and cell wall-binding domain (CBD) from Enterococcus faecalis phage lysin PlyV12. ClyQ had an exceptionally broad host range targeting streptococci, staphylococci, E. faecalis, and E. rhusiopathiae. ClyQ combined with mupirocin (2.64 log reduction) was more effective at treating S. aureus skin infections than ClyQ (0.46 log reduction) and mupirocin (2.23 log reduction) alone. Of equal importance, none of S. aureus ATCC 29213 or S3 exposed to ClyQ developed resistance, and the combination of ClyQ and mupirocin delayed the development of mupirocin resistance. Collectively, chimeric lysin ClyQ enriches the reservoirs for treating S. aureus infections. Our findings may provide a way to alleviate the current antibiotic resistance crisis. IMPORTANCE Staphylococcus aureus, as an Enterococcus faecium, Staphylococcus aureus, Klebsiella pneumoniae, Acinetobacter baumannii, Pseudomonas aeruginosa, and Enterobacter species (ESKAPE) pathogen, can escape the elimination of existing antibiotics. At present, phages and phage lysins against S. aureus infections are considered alternative antibacterial agents. However, the development of broad-spectrum chimeric phage lysins to cooperate with antibiotics against S. aureus infections remains at its initial stage. In this study, we found that the broad-host-range chimeric lysin ClyQ can synergize with mupirocin to treat S. aureus skin infections. Furthermore, the development of S. aureus resistance to mupirocin is delayed by the combination of ClyQ and mupirocin in vitro. Our results bring research attention toward the development of chimeric lysin that cooperates with antibiotics to overcome bacterial infections.
Collapse
Affiliation(s)
- Xiao-chao Duan
- State Key Laboratory of Agricultural Microbiology, Huazhong Agricultural University, Wuhan, China
- College of Veterinary Medicine, Huazhong Agricultural University, Wuhan, China
- Key Laboratory of Preventive Veterinary Medicine in Hubei Province, The Cooperative Innovation Center for Sustainable Pig Production, Wuhan, China
| | - Xin-xin Li
- State Key Laboratory of Agricultural Microbiology, Huazhong Agricultural University, Wuhan, China
- College of Veterinary Medicine, Huazhong Agricultural University, Wuhan, China
- Key Laboratory of Preventive Veterinary Medicine in Hubei Province, The Cooperative Innovation Center for Sustainable Pig Production, Wuhan, China
| | - Xiang-min Li
- State Key Laboratory of Agricultural Microbiology, Huazhong Agricultural University, Wuhan, China
- College of Veterinary Medicine, Huazhong Agricultural University, Wuhan, China
- Key Laboratory of Preventive Veterinary Medicine in Hubei Province, The Cooperative Innovation Center for Sustainable Pig Production, Wuhan, China
| | - Shuang Wang
- State Key Laboratory of Agricultural Microbiology, Huazhong Agricultural University, Wuhan, China
- College of Veterinary Medicine, Huazhong Agricultural University, Wuhan, China
- Key Laboratory of Preventive Veterinary Medicine in Hubei Province, The Cooperative Innovation Center for Sustainable Pig Production, Wuhan, China
| | - Fen-qiang Zhang
- State Key Laboratory of Agricultural Microbiology, Huazhong Agricultural University, Wuhan, China
- College of Veterinary Medicine, Huazhong Agricultural University, Wuhan, China
- Key Laboratory of Preventive Veterinary Medicine in Hubei Province, The Cooperative Innovation Center for Sustainable Pig Production, Wuhan, China
| | - Ping Qian
- State Key Laboratory of Agricultural Microbiology, Huazhong Agricultural University, Wuhan, China
- College of Veterinary Medicine, Huazhong Agricultural University, Wuhan, China
- Key Laboratory of Preventive Veterinary Medicine in Hubei Province, The Cooperative Innovation Center for Sustainable Pig Production, Wuhan, China
| |
Collapse
|
4
|
Alreja AB, Linden SB, Lee HR, Chao KL, Herzberg O, Nelson DC. Understanding the Molecular Basis for Homodimer Formation of the Pneumococcal Endolysin Cpl-1. ACS Infect Dis 2023; 9:1092-1104. [PMID: 37126660 PMCID: PMC10577085 DOI: 10.1021/acsinfecdis.2c00627] [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] [Indexed: 05/03/2023]
Abstract
The rise of multi-drug-resistant bacteria that cannot be treated with traditional antibiotics has prompted the search for alternatives to combat bacterial infections. Endolysins, which are bacteriophage-derived peptidoglycan hydrolases, are attractive tools in this fight. Several studies have already demonstrated the efficacy of endolysins in targeting bacterial infections. Endolysins encoded by bacteriophages that infect Gram-positive bacteria typically possess an N-terminal catalytic domain and a C-terminal cell-wall binding domain (CWBD). In this study, we have uncovered the molecular mechanisms that underlie formation of a homodimer of Cpl-1, an endolysin that targets Streptococcus pneumoniae. Here, we use site-directed mutagenesis, analytical size exclusion chromatography, and analytical ultracentrifugation to disprove a previous suggestion that three residues at the N-terminus of the CWBD are involved in the formation of a Cpl-1 dimer in the presence of choline in solution. We conclusively show that the C-terminal tail region of Cpl-1 is involved in formation of the dimer. Alanine scanning mutagenesis generated various tail mutant constructs that allowed identification of key residues that mediate Cpl-1 dimer formation. Finally, our results allowed identification of a consensus sequence (FxxEPDGLIT) required for choline-dependent dimer formation─a sequence that occurs frequently in pneumococcal autolysins and endolysins. These findings shed light on the mechanisms of Cpl-1 and related enzymes and can be used to inform future engineering efforts for their therapeutic development against S. pneumoniae.
Collapse
Affiliation(s)
- Adit B Alreja
- Institute for Bioscience and Biotechnology Research, Rockville, Maryland 20850, USA
- Biological Sciences Graduate Program - Molecular and Cellular Biology Concentration, University of Maryland, College Park, Maryland 20742, USA
| | - Sara B Linden
- Institute for Bioscience and Biotechnology Research, Rockville, Maryland 20850, USA
| | - Harrison R Lee
- Institute for Bioscience and Biotechnology Research, Rockville, Maryland 20850, USA
| | - Kinlin L Chao
- Institute for Bioscience and Biotechnology Research, Rockville, Maryland 20850, USA
| | - Osnat Herzberg
- Institute for Bioscience and Biotechnology Research, Rockville, Maryland 20850, USA
- Department of Biochemistry and Chemistry, University of Maryland, College Park, Maryland 20742, USA
| | - Daniel C Nelson
- Institute for Bioscience and Biotechnology Research, Rockville, Maryland 20850, USA
- Department of Veterinary Medicine, University of Maryland, College Park, Maryland 20742, USA
| |
Collapse
|
5
|
Liu H, Hu Z, Li M, Yang Y, Lu S, Rao X. Therapeutic potential of bacteriophage endolysins for infections caused by Gram-positive bacteria. J Biomed Sci 2023; 30:29. [PMID: 37101261 PMCID: PMC10131408 DOI: 10.1186/s12929-023-00919-1] [Citation(s) in RCA: 8] [Impact Index Per Article: 8.0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/30/2023] [Accepted: 04/14/2023] [Indexed: 04/28/2023] Open
Abstract
Gram-positive (G+) bacterial infection is a great burden to both healthcare and community medical resources. As a result of the increasing prevalence of multidrug-resistant G+ bacteria such as methicillin-resistant Staphylococcus aureus (MRSA), novel antimicrobial agents must urgently be developed for the treatment of infections caused by G+ bacteria. Endolysins are bacteriophage (phage)-encoded enzymes that can specifically hydrolyze the bacterial cell wall and quickly kill bacteria. Bacterial resistance to endolysins is low. Therefore, endolysins are considered promising alternatives for solving the mounting resistance problem. In this review, endolysins derived from phages targeting G+ bacteria were classified based on their structural characteristics. The active mechanisms, efficacy, and advantages of endolysins as antibacterial drug candidates were summarized. Moreover, the remarkable potential of phage endolysins in the treatment of G+ bacterial infections was described. In addition, the safety of endolysins, challenges, and possible solutions were addressed. Notwithstanding the limitations of endolysins, the trends in development indicate that endolysin-based drugs will be approved in the near future. Overall, this review presents crucial information of the current progress involving endolysins as potential therapeutic agents, and it provides a guideline for biomaterial researchers who are devoting themselves to fighting against bacterial infections.
Collapse
Affiliation(s)
- He Liu
- Department of Microbiology, College of Basic Medical Sciences, Key Laboratory of Microbial Engineering Under the Educational Committee in Chongqing, Army Medical University, Chongqing, 400038, China
| | - Zhen Hu
- Department of Microbiology, College of Basic Medical Sciences, Key Laboratory of Microbial Engineering Under the Educational Committee in Chongqing, Army Medical University, Chongqing, 400038, China
| | - Mengyang Li
- Department of Microbiology, School of Medicine, Chongqing University, Chongqing, 400044, China
| | - Yi Yang
- Department of Microbiology, College of Basic Medical Sciences, Key Laboratory of Microbial Engineering Under the Educational Committee in Chongqing, Army Medical University, Chongqing, 400038, China
| | - Shuguang Lu
- Department of Microbiology, College of Basic Medical Sciences, Key Laboratory of Microbial Engineering Under the Educational Committee in Chongqing, Army Medical University, Chongqing, 400038, China.
| | - Xiancai Rao
- Department of Microbiology, College of Basic Medical Sciences, Key Laboratory of Microbial Engineering Under the Educational Committee in Chongqing, Army Medical University, Chongqing, 400038, China.
| |
Collapse
|
6
|
Mehmood Khan F, Manohar P, Singh Gondil V, Mehra N, Kayode Oyejobi G, Odiwuor N, Ahmad T, Huang G. The applications of animal models in phage therapy: An update. Hum Vaccin Immunother 2023; 19:2175519. [PMID: 36935353 PMCID: PMC10072079 DOI: 10.1080/21645515.2023.2175519] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 03/21/2023] Open
Abstract
The rapid increase in antibiotic resistance presents a dire situation necessitating the need for alternative therapeutic agents. Among the current alternative therapies, phage therapy (PT) is promising. This review extensively summarizes preclinical PT approaches in various in-vivo models. PT has been evaluated in several recent clinical trials. However, there are still several unanswered concerns due to a lack of appropriate regulation and pharmacokinetic data regarding the application of phages in human therapeutic procedures. In this review, we also presented the current state of PT and considered how animal models can be used to adapt these therapies for humans. The development of realistic solutions to circumvent these constraints is critical for advancing this technology.
Collapse
Affiliation(s)
- Fazal Mehmood Khan
- College of Civil and Transportation Engineering, Shenzhen University, Shenzhen, China.,Shenzhen Key Laboratory of Marine Microbiome Engineering, Institute for Advanced Study, Shenzhen University, Shenzhen, China.,Institute for Innovative Development of Food Industry, Shenzhen University, Shenzhen, China.,Key Laboratory of Special Pathogens and Biosafety, Center for Biosafety Mega-Science, Wuhan Institute of Virology, Chinese Academy of Sciences, Wuhan, Hubei, China
| | - Prasanth Manohar
- School of Biosciences and Technology, Vellore Institute of Technology, Vellore, India
| | - Vijay Singh Gondil
- Key Laboratory of Special Pathogens and Biosafety, Center for Biosafety Mega-Science, Wuhan Institute of Virology, Chinese Academy of Sciences, Wuhan, Hubei, China.,Department of Microbiology and Immunology, University of Rochester School of Medicine and Dentistry, Rochester, New York, USA
| | - Nancy Mehra
- Department of Pediatrics, Advanced Pediatrics Centre, Postgraduate Institute of Medical Education and Research, Chandigarh, India
| | - Greater Kayode Oyejobi
- Key Laboratory of Special Pathogens and Biosafety, Center for Biosafety Mega-Science, Wuhan Institute of Virology, Chinese Academy of Sciences, Wuhan, Hubei, China.,Department of Microbiology, Osun State University, Osogbo, Nigeria.,School of Pharmaceutical Sciences, Wuhan University, Wuhan, Hubei, China
| | - Nelson Odiwuor
- Key Laboratory of Special Pathogens and Biosafety, Center for Biosafety Mega-Science, Wuhan Institute of Virology, Chinese Academy of Sciences, Wuhan, Hubei, China.,International College, University of Chinese Academy of Sciences, Beijing, China.,Microbiology, Sino-Africa Joint Research Centre, Nairobi, Kenya
| | - Tauseef Ahmad
- Department of Epidemiology and Health Statistics, School of Public Health, Southeast University, Nanjing, China
| | - Guangtao Huang
- Department of Burn and Plastic Surgery, Shenzhen Institute of Translational Medicine, The First Affiliated Hospital of Shenzhen University, Shenzhen, China.,Department of Burns and Plastic Surgery, Affiliated Hospital of Zunyi Medical University, Zunyi, China.,Department of Plastic and Reconstructive Surgery, Shanghai Ninth People's Hospital, Shanghai Jiao Tong University School of Medicine, Shanghai, China
| |
Collapse
|
7
|
Wong KY, Megat Mazhar Khair MH, Song AAL, Masarudin MJ, Chong CM, In LLA, Teo MYM. Endolysins against Streptococci as an antibiotic alternative. Front Microbiol 2022; 13:935145. [PMID: 35983327 PMCID: PMC9378833 DOI: 10.3389/fmicb.2022.935145] [Citation(s) in RCA: 8] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/03/2022] [Accepted: 07/07/2022] [Indexed: 11/21/2022] Open
Abstract
Multi-drug resistance has called for a race to uncover alternatives to existing antibiotics. Phage therapy is one of the explored alternatives, including the use of endolysins, which are phage-encoded peptidoglycan hydrolases responsible for bacterial lysis. Endolysins have been extensively researched in different fields, including medicine, food, and agricultural applications. While the target specificity of various endolysins varies greatly between species, this current review focuses specifically on streptococcal endolysins. Streptococcus spp. causes numerous infections, from the common strep throat to much more serious life-threatening infections such as pneumonia and meningitis. It is reported as a major crisis in various industries, causing systemic infections associated with high mortality and morbidity, as well as economic losses, especially in the agricultural industry. This review highlights the types of catalytic and cell wall-binding domains found in streptococcal endolysins and gives a comprehensive account of the lytic ability of both native and engineered streptococcal endolysins studied thus far, as well as its potential application across different industries. Finally, it gives an overview of the advantages and limitations of these enzyme-based antibiotics, which has caused the term enzybiotics to be conferred to it.
Collapse
Affiliation(s)
- Kuan Yee Wong
- Department of Biotechnology, Faculty of Applied Sciences, UCSI University, Kuala Lumpur, Malaysia
| | - Megat Hamzah Megat Mazhar Khair
- Department of Microbiology, Faculty of Biotechnology and Biomolecular Sciences, Universiti Putra Malaysia, Selangor, Malaysia
| | - Adelene Ai-Lian Song
- Department of Microbiology, Faculty of Biotechnology and Biomolecular Sciences, Universiti Putra Malaysia, Selangor, Malaysia
| | - Mas Jaffri Masarudin
- Department of Cell and Molecular Biology, Faculty of Biotechnology and Biomolecular Sciences, Universiti Putra Malaysia, Selangor, Malaysia
| | - Chou Min Chong
- Department of Aquaculture, Faculty of Agriculture, Universiti Putra Malaysia, Selangor, Malaysia
| | - Lionel Lian Aun In
- Department of Biotechnology, Faculty of Applied Sciences, UCSI University, Kuala Lumpur, Malaysia
- Lionel Lian Aun In,
| | - Michelle Yee Mun Teo
- Department of Biotechnology, Faculty of Applied Sciences, UCSI University, Kuala Lumpur, Malaysia
- *Correspondence: Michelle Yee Mun Teo,
| |
Collapse
|
8
|
Chang RYK, Nang SC, Chan HK, Li J. Novel antimicrobial agents for combating antibiotic-resistant bacteria. Adv Drug Deliv Rev 2022; 187:114378. [PMID: 35671882 DOI: 10.1016/j.addr.2022.114378] [Citation(s) in RCA: 35] [Impact Index Per Article: 17.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/14/2022] [Revised: 05/26/2022] [Accepted: 05/26/2022] [Indexed: 12/16/2022]
Abstract
Antibiotic therapy has become increasingly ineffective against bacterial infections due to the rise of resistance. In particular, ESKAPE pathogens (Enterococcus faecium, Staphylococcus aureus, Klebsiella pneumoniae, Acinetobacter baumannii, Pseudomonas aeruginosa, and Enterobacter species) have caused life-threatening infections in humans and represent a major global health threat due to a high degree of antibiotic resistance. To respond to this urgent call, novel strategies are urgently needed, such as bacteriophages (or phages), phage-encoded enzymes, immunomodulators and monoclonal antibodies. This review critically analyses these promising antimicrobial therapies for the treatment of multidrug-resistant bacterial infections. Recent advances in these novel therapeutic strategies are discussed, focusing on preclinical and clinical investigations, as well as combinatorial approaches. In this 'Bad Bugs, No Drugs' era, novel therapeutic strategies can play a key role in treating deadly infections and help extend the lifetime of antibiotics.
Collapse
|
9
|
Ho MKY, Zhang P, Chen X, Xia J, Leung SSY. Bacteriophage endolysins against gram-positive bacteria, an overview on the clinical development and recent advances on the delivery and formulation strategies. Crit Rev Microbiol 2021; 48:303-326. [PMID: 34478359 DOI: 10.1080/1040841x.2021.1962803] [Citation(s) in RCA: 11] [Impact Index Per Article: 3.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/21/2023]
Abstract
Facing the increasing threat of multi-drug antimicrobial resistance (AMR), humans strive to search for antibiotic drug candidates and antibacterial alternatives from all possible places, from soils in remote areas to deep in the sea. In this "gold rush for antibacterials," researchers turn to the natural enemy of bacterial cells, bacteriophage (phages), and find them a rich source of weapons for AMR bacteria. Endolysins (lysins), the enzymes phages use to break the bacterial cells from within, have been shown to be highly selective and efficient in killing their target bacteria from outside while maintaining a low occurrence of bacterial resistance. In this review, we start with the structures and mechanisms of action of lysins against Gram-positive (GM+) bacteria. The developmental history of lysins is also outlined. Then, we detail the latest preclinical and clinical research on their safety and efficacy against GM+ bacteria, focusing on the formulation strategies of these enzymes. Finally, the challenges and potential hurdles are discussed. Notwithstanding these limitations, the trends in development indicate that the first, approved lysin drugs will be available soon in the near future. Overall, this review presents a timely summary of the current progress on lysins as antibacterial enzymes for AMR GM+ bacteria, and provides a guidebook for biomaterial researchers who are dedicating themselves to the battle against bacterial infections.
Collapse
Affiliation(s)
- Marco Kai Yuen Ho
- School of Pharmacy, The Chinese University of Hong Kong, Hong Kong, China
| | - Pengfei Zhang
- School of Pharmacy, The Chinese University of Hong Kong, Hong Kong, China
| | - Xi Chen
- Department of Chemistry, The Chinese University of Hong Kong, Hong Kong, China
| | - Jiang Xia
- Department of Chemistry, The Chinese University of Hong Kong, Hong Kong, China
| | | |
Collapse
|
10
|
Li X, Wang S, Nyaruaba R, Liu H, Yang H, Wei H. A Highly Active Chimeric Lysin with a Calcium-Enhanced Bactericidal Activity against Staphylococcus aureus In Vitro and In Vivo. Antibiotics (Basel) 2021; 10:antibiotics10040461. [PMID: 33921682 PMCID: PMC8074178 DOI: 10.3390/antibiotics10040461] [Citation(s) in RCA: 15] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/23/2021] [Revised: 04/16/2021] [Accepted: 04/17/2021] [Indexed: 01/21/2023] Open
Abstract
Lysins, including chimeric lysins, have recently been explored as novel promising alternatives to failing antibiotics in treating multi-drug resistant (MDR) pathogens, including methicillin-resistant Staphylococcus aureus (MRSA). Herein, by fusing the CHAP (cysteine, histidine-dependent amidohydrolase/peptidase) catalytic domain from the Ply187 lysin with the non-SH3b cell-wall binding domain from the LysSA97 lysin, a new chimeric lysin ClyC was constructed with Ca2+-enhanced bactericidal activity against all S. aureus strains tested, including MRSA. Notably, treating S. aureus with 50 μg/mL of ClyC in the presence of 100 μM Ca2+ lead to a reduction of 9 Log10 (CFU/mL) in viable bacterial number, which was the first time to observe a lysin showing such a high activity. In addition, the effective concentration of ClyC could be decreased dramatically from 12 to 1 μg/mL by combination with 0.3 μg/mL of penicillin G. In a mouse model of S. aureus bacteremia, a single intraperitoneal administration of 0.1 mg/mouse of ClyC significantly improved the survival rates and reduced 2 Log10 (CFU/mL) of the bacterial burdens in the organs of the infected mice. ClyC was also found stable after lyophilization without cryoprotectants. Based on the above observations, ClyC could be a promising candidate against S. aureus infections.
Collapse
Affiliation(s)
- Xiaohong Li
- CAS Key Laboratory of Emerging Pathogens and Biosafety, Centre for Biosafety Mega-Sciences, Wuhan Institute of Virology, Chinese Academy of Sciences, Wuhan 430071, China; (X.L.); (S.W.); (R.N.); (H.L.)
- College of Life Sciences, University of Chinese Academy of Sciences, Beijing 100049, China
| | - Shujuan Wang
- CAS Key Laboratory of Emerging Pathogens and Biosafety, Centre for Biosafety Mega-Sciences, Wuhan Institute of Virology, Chinese Academy of Sciences, Wuhan 430071, China; (X.L.); (S.W.); (R.N.); (H.L.)
- College of Life Sciences, University of Chinese Academy of Sciences, Beijing 100049, China
| | - Raphael Nyaruaba
- CAS Key Laboratory of Emerging Pathogens and Biosafety, Centre for Biosafety Mega-Sciences, Wuhan Institute of Virology, Chinese Academy of Sciences, Wuhan 430071, China; (X.L.); (S.W.); (R.N.); (H.L.)
- College of Life Sciences, University of Chinese Academy of Sciences, Beijing 100049, China
- Sino-Africa Joint Research Center, Chinese Academy of Sciences, Wuhan 430074, China
| | - Huan Liu
- CAS Key Laboratory of Emerging Pathogens and Biosafety, Centre for Biosafety Mega-Sciences, Wuhan Institute of Virology, Chinese Academy of Sciences, Wuhan 430071, China; (X.L.); (S.W.); (R.N.); (H.L.)
- College of Life Sciences, University of Chinese Academy of Sciences, Beijing 100049, China
| | - Hang Yang
- CAS Key Laboratory of Emerging Pathogens and Biosafety, Centre for Biosafety Mega-Sciences, Wuhan Institute of Virology, Chinese Academy of Sciences, Wuhan 430071, China; (X.L.); (S.W.); (R.N.); (H.L.)
- Correspondence: (H.Y.); (H.W.); Tel.: +86-27-51861078 (H.Y.); +86-27-51861077 (H.W.)
| | - Hongping Wei
- CAS Key Laboratory of Emerging Pathogens and Biosafety, Centre for Biosafety Mega-Sciences, Wuhan Institute of Virology, Chinese Academy of Sciences, Wuhan 430071, China; (X.L.); (S.W.); (R.N.); (H.L.)
- Correspondence: (H.Y.); (H.W.); Tel.: +86-27-51861078 (H.Y.); +86-27-51861077 (H.W.)
| |
Collapse
|
11
|
Linden SB, Alreja AB, Nelson DC. Application of bacteriophage-derived endolysins to combat streptococcal disease: current state and perspectives. Curr Opin Biotechnol 2021; 68:213-220. [PMID: 33529969 DOI: 10.1016/j.copbio.2021.01.012] [Citation(s) in RCA: 14] [Impact Index Per Article: 4.7] [Reference Citation Analysis] [Abstract] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/02/2021] [Revised: 01/15/2021] [Accepted: 01/18/2021] [Indexed: 12/20/2022]
Abstract
The decline in new antibiotic candidates combined with an increase in antibiotic-resistance necessitates development of alternative antimicrobials. Bacteriophage-encoded endolysins (lysins) are a class of peptidoglycan hydrolases that have been proposed to fill this antimicrobial void. The past 20 years has seen a dramatic expansion of studies on endolysin discovery, structure/function, engineering, immunogenicity, toxicity/safety, and efficacy in animal models. These collective efforts have led to current human clinical trials on at least three different endolysins that are antimicrobial toward staphylococcal species. It can be anticipated that endolysins targeting streptococcal species may be next in line for translational development. Notably, streptococcal diseases largely manifest at accessible mucous membranes, which should be beneficial for protein therapeutics. Additionally, there are a number of well-identified streptococcal diseases in both humans and animals that are associated with a single species, further favoring a targeted endolysin therapeutic.
Collapse
Affiliation(s)
- Sara B Linden
- Institute for Bioscience and Biotechnology Research, University of Maryland, Rockville, MD 20850, USA
| | - Adit B Alreja
- Institute for Bioscience and Biotechnology Research, University of Maryland, Rockville, MD 20850, USA
| | - Daniel C Nelson
- Institute for Bioscience and Biotechnology Research, University of Maryland, Rockville, MD 20850, USA; Department of Veterinary Medicine, University of Maryland, College Park, MD 20742, USA.
| |
Collapse
|
12
|
Binte Muhammad Jai HS, Dam LC, Tay LS, Koh JJW, Loo HL, Kline KA, Goh BC. Engineered Lysins With Customized Lytic Activities Against Enterococci and Staphylococci. Front Microbiol 2020; 11:574739. [PMID: 33324362 PMCID: PMC7724435 DOI: 10.3389/fmicb.2020.574739] [Citation(s) in RCA: 9] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/21/2020] [Accepted: 10/22/2020] [Indexed: 12/12/2022] Open
Abstract
The emergence of multidrug-resistant bacteria has made minor bacterial infections incurable with many existing antibiotics. Lysins are phage-encoded peptidoglycan hydrolases that have demonstrated therapeutic potential as a novel class of antimicrobials. The modular architecture of lysins enables the functional domains – catalytic domain (CD) and cell wall binding domain (CBD) – to be shuffled to create novel lysins. The CD is classically thought to be only involved in peptidoglycan hydrolysis whereas the CBD dictates the lytic spectrum of a lysin. While there are many studies that extended the lytic spectrum of a lysin by domain swapping, few have managed to introduce species specificity in a chimeric lysin. In this work, we constructed two chimeric lysins by swapping the CBDs of two parent lysins with different lytic spectra against enterococci and staphylococci. We showed that these chimeric lysins exhibited customized lytic spectra distinct from the parent lysins. Notably, the chimeric lysin P10N-V12C, which comprises a narrow-spectrum CD fused with a broad-spectrum CBD, displayed species specificity not lysing Enterococcus faecium while targeting Enterococcus faecalis and staphylococci. Such species specificity can be attributed to the narrow-spectrum CD of the chimeric lysin. Using flow cytometry and confocal microscopy, we found that the E. faecium cells that were treated with P10N-V12C are less viable with compromised membranes yet remained morphologically intact. Our results suggest that while the CBD is a major determinant of the lytic spectrum of a lysin, the CD is also responsible in the composition of the final lytic spectrum, especially when it pertains to species-specificity.
Collapse
Affiliation(s)
- Hana Sakina Binte Muhammad Jai
- Antimicrobial Resistance Interdisciplinary Research Group, Singapore-MIT Alliance for Research and Technology Centre, Singapore, Singapore
| | - Linh Chi Dam
- Antimicrobial Resistance Interdisciplinary Research Group, Singapore-MIT Alliance for Research and Technology Centre, Singapore, Singapore
| | - Lowella Servito Tay
- Antimicrobial Resistance Interdisciplinary Research Group, Singapore-MIT Alliance for Research and Technology Centre, Singapore, Singapore
| | - Jodi Jia Wei Koh
- Antimicrobial Resistance Interdisciplinary Research Group, Singapore-MIT Alliance for Research and Technology Centre, Singapore, Singapore
| | - Hooi Linn Loo
- Antimicrobial Resistance Interdisciplinary Research Group, Singapore-MIT Alliance for Research and Technology Centre, Singapore, Singapore
| | - Kimberly A Kline
- Antimicrobial Resistance Interdisciplinary Research Group, Singapore-MIT Alliance for Research and Technology Centre, Singapore, Singapore.,Singapore Centre for Environmental Life Sciences Engineering, School of Biological Sciences, Nanyang Technological University, Singapore, Singapore
| | - Boon Chong Goh
- Antimicrobial Resistance Interdisciplinary Research Group, Singapore-MIT Alliance for Research and Technology Centre, Singapore, Singapore
| |
Collapse
|
13
|
A Choline-Recognizing Monomeric Lysin, ClyJ-3m, Shows Elevated Activity against Streptococcus pneumoniae. Antimicrob Agents Chemother 2020; 64:AAC.00311-20. [PMID: 32958710 DOI: 10.1128/aac.00311-20] [Citation(s) in RCA: 9] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/17/2020] [Accepted: 09/10/2020] [Indexed: 12/29/2022] Open
Abstract
Streptococcus pneumoniae is a leading pathogen for bacterial pneumonia, which can be treated with bacteriophage lysins harboring a conserved choline binding module (CBM). Such lysins regularly function as choline-recognizing dimers. Previously, we reported a pneumococcus-specific lysin ClyJ comprising the binding domain from the putative endolysin gp20 from the Streptococcus phage SPSL1 and the CHAP (cysteine, histidine-dependent amidohydrolase/peptidase) catalytic domain from the PlyC lysin. A variant of ClyJ with a shortened linker, i.e., ClyJ-3, shows improved activity and reduced cytotoxicity. Resembling typical CBM-containing lysins, ClyJ-3 dimerized upon binding with choline. Herein, we further report a choline-recognizing variant of ClyJ-3, i.e., ClyJ-3m, constructed by deleting its C-terminal tail. Biochemical characterization showed that ClyJ-3m remains a monomer after it binds to choline yet exhibits improved bactericidal activity against multiple pneumococcal strains with different serotypes. In an S. pneumoniae-infected bacteremia model, a single intraperitoneal administration of 2.32 μg/mouse of ClyJ-3m showed 70% protection, while only 20% of mice survived in the group receiving an equal dose of ClyJ-3 (P < 0.05). A pharmacokinetic analysis following single intravenously doses of 0.29 and 1.16 mg/kg of ClyJ-3 or ClyJ-3m in BALB/c mice revealed that ClyJ-3m shows a similar half-life but less clearance and a greater area under curve than ClyJ-3. Taken together, the choline-recognizing monomer ClyJ-3m exhibited enhanced bactericidal activity and improved pharmacokinetic proprieties compared to those of its parental ClyJ-3 lysin. Our study also provides a new way for rational design and programmed engineering of lysins targeting S. pneumoniae.
Collapse
|
14
|
Zhou B, Zhen X, Zhou H, Zhao F, Fan C, Perčulija V, Tong Y, Mi Z, Ouyang S. Structural and functional insights into a novel two-component endolysin encoded by a single gene in Enterococcus faecalis phage. PLoS Pathog 2020; 16:e1008394. [PMID: 32176738 PMCID: PMC7098653 DOI: 10.1371/journal.ppat.1008394] [Citation(s) in RCA: 20] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/25/2019] [Revised: 03/26/2020] [Accepted: 02/10/2020] [Indexed: 11/18/2022] Open
Abstract
Using bacteriophage-derived endolysins as an alternative strategy for fighting drug-resistant bacteria has recently been garnering renewed interest. However, their application is still hindered by their narrow spectra of activity. In our previous work, we demonstrated that the endolysin LysIME-EF1 possesses efficient bactericidal activity against multiple strains of Enterococcus faecalis (E. faecalis). Herein, we observed an 8 kDa fragment and hypothesized that it contributes to LysIME-EF1 lytic activity. To examine our hypothesis, we determined the structure of LysIME-EF1 at 1.75 Å resolution. LysIME-EF1 exhibits a unique architecture in which one full-length LysIME-EF1 forms a tetramer with three additional C-terminal cell-wall binding domains (CBDs) that correspond to the abovementioned 8 kDa fragment. Furthermore, we identified an internal ribosomal binding site (RBS) and alternative start codon within LysIME-EF1 gene, which are demonstrated to be responsible for the translation of the truncated CBD. To elucidate the molecular mechanism for the lytic activity of LysIME-EF1, we combined mutagenesis, lytic activity assays and in vivo animal infection experiments. The results confirmed that the additional LysIME-EF1 CBDs are important for LysIME-EF1 architecture and its lytic activity. To our knowledge, this is the first determined structure of multimeric endolysin encoded by a single gene in E. faecalis phages. As such, it may provide valuable insights into designing potent endolysins against the opportunistic pathogen E. faecalis. LysIME-EF1, an endolysin that lyses E. faecalis, displays the prospect of treating E. faecalis infection. We find that the C-terminal cell-wall binding domain (CBD) is important for the lytic activity of LysIME-EF1. By determining the crystal structures of wild type (WT) LysIME-EF1 and its C-terminal CBD, this study reveals how the holoenzyme is organized to carry out its highly efficient lytic activity. Our finding provides structural and functional evidence that LysIME-EF1 belongs to a unique two-component multimeric endolysin encoded by a single gene.
Collapse
Affiliation(s)
- Biao Zhou
- The Key Laboratory of Innate Immune Biology of Fujian Province, Provincial University Key Laboratory of Cellular Stress Response and Metabolic Regulation, Biomedical Research Center of South China, Key Laboratory of OptoElectronic Science and Technology for Medicine of the Ministry of Education, College of Life Sciences, Fujian Normal University, Fuzhou, China
| | - Xiangkai Zhen
- The Key Laboratory of Innate Immune Biology of Fujian Province, Provincial University Key Laboratory of Cellular Stress Response and Metabolic Regulation, Biomedical Research Center of South China, Key Laboratory of OptoElectronic Science and Technology for Medicine of the Ministry of Education, College of Life Sciences, Fujian Normal University, Fuzhou, China
- Laboratory for Marine Biology and Biotechnology, Pilot National Laboratory for Marine Science and Technology (Qingdao), Qingdao, China
| | - Huan Zhou
- Shanghai Institute of Applied Physics, Chinese Academy of Sciences, Shanghai, China
| | - Feiyang Zhao
- Beijing Advanced Innovation Center for Soft Matter Science and Engineering (BAIC-SM), College of Life Science and Technology, Beijing University of Chemical Technology, Beijing, China
| | - Chenpeng Fan
- Department of Biochemistry and Molecular Biology, School of Basic Medical Sciences, Wuhan University, Wuhan, China
| | - Vanja Perčulija
- The Key Laboratory of Innate Immune Biology of Fujian Province, Provincial University Key Laboratory of Cellular Stress Response and Metabolic Regulation, Biomedical Research Center of South China, Key Laboratory of OptoElectronic Science and Technology for Medicine of the Ministry of Education, College of Life Sciences, Fujian Normal University, Fuzhou, China
| | - Yigang Tong
- Beijing Advanced Innovation Center for Soft Matter Science and Engineering (BAIC-SM), College of Life Science and Technology, Beijing University of Chemical Technology, Beijing, China
| | - Zhiqiang Mi
- State Key Laboratory of Pathogen and Biosecurity, Beijing Institute of Microbiology and Epidemiology, Beijing, China
- * E-mail: (ZM); (SO)
| | - Songying Ouyang
- The Key Laboratory of Innate Immune Biology of Fujian Province, Provincial University Key Laboratory of Cellular Stress Response and Metabolic Regulation, Biomedical Research Center of South China, Key Laboratory of OptoElectronic Science and Technology for Medicine of the Ministry of Education, College of Life Sciences, Fujian Normal University, Fuzhou, China
- Laboratory for Marine Biology and Biotechnology, Pilot National Laboratory for Marine Science and Technology (Qingdao), Qingdao, China
- * E-mail: (ZM); (SO)
| |
Collapse
|
15
|
Linker Editing of Pneumococcal Lysin ClyJ Conveys Improved Bactericidal Activity. Antimicrob Agents Chemother 2020; 64:AAC.01610-19. [PMID: 31767724 DOI: 10.1128/aac.01610-19] [Citation(s) in RCA: 12] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/08/2019] [Accepted: 11/18/2019] [Indexed: 12/12/2022] Open
Abstract
Streptococcus pneumoniae is a leading human pathogen uniquely characterized by choline moieties on the bacterial surface. Our previous work reported a pneumococcus-specific chimeric lysin, ClyJ, which combines the CHAP (cysteine, histidine-dependent amidohydrolase/peptidase) enzymatically active domain (EAD) from the PlyC lysin and the cell wall binding domain (CBD) from the phage SPSL1 lysin, which imparts choline binding specificity. Here, we demonstrate that the lytic activity of ClyJ can be further improved by editing the linker sequence adjoining the EAD and CBD. Keeping the net charge of the linker constant, we constructed three ClyJ variants containing different lengths of linker sequence. Circular dichroism showed that linker editing has only minor effects on the folding of the EAD and CBD. However, thermodynamic examination combined with biochemical analysis demonstrated that one variant, ClyJ-3, with the shortest linker, displayed improved thermal stability and bactericidal activity, as well as reduced cytotoxicity. In a pneumococcal mouse infection model, ClyJ-3 showed significant protective efficacy compared to that of the ClyJ parental lysin or the Cpl-1 lysin, with 100% survival at a single ClyJ-3 intraperitoneal dose of 100 μg/mouse. Moreover, a ClyJ-3 dose of 2 μg/mouse had the same efficacy as a ClyJ dose of 40 μg/mouse, suggesting a 20-fold improvement in vivo Taking these results together, the present study not only describes a promising pneumococcal lysin with improved potency, i.e., ClyJ-3, but also implies for the first time that the linker sequence plays an important role in determining the activity of a chimeric lysin, providing insight for future lysin engineering studies.
Collapse
|
16
|
Construction and characterization of a chimeric lysin ClyV with improved bactericidal activity against Streptococcus agalactiae in vitro and in vivo. Appl Microbiol Biotechnol 2020; 104:1609-1619. [PMID: 31900556 DOI: 10.1007/s00253-019-10325-z] [Citation(s) in RCA: 18] [Impact Index Per Article: 4.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/07/2019] [Revised: 12/06/2019] [Accepted: 12/15/2019] [Indexed: 01/21/2023]
Abstract
The emergence of antibiotic-resistant beta-hemolytic Streptococcus agalactiae strains poses increasing threat to human beings globally. As an attempt to create a novel lysin with improved activity against S. agalactiae, a chimeric lysin, ClyV, was constructed by fusing the enzymatically active domain (EAD) from PlyGBS lysin (GBS180) and the cell wall binding domain (CBD) from PlyV12 lysin (V12CBD). Plate lysis assay combined with lytic kinetic analysis demonstrated that ClyV has improved activity than its parental enzymatic domain GBS180 against multiple streptococci. Biochemical characterization showed that ClyV is active from pH 7 to 10, with the optimum pH of 9, and is stable under NaCl concentration of < 500 mM. In a S. agalactiae infection model, a single intraperitoneally administration of 0.1 mg/mouse of ClyV protected 100% mice, while it was observed that ~ 29% survive in group that received a single dose of 0.1 mg/mouse of GBS180. Moreover, a high dose of 0.8 mg/mouse ClyV did not show any adverse effects to the health or survival rate of the mice. Considering the robust bactericidal activity and good safety profile of ClyV, it represents a potential candidate for the treatment of S. agalactiae infections.
Collapse
|
17
|
Caflisch KM, Suh GA, Patel R. Biological challenges of phage therapy and proposed solutions: a literature review. Expert Rev Anti Infect Ther 2019; 17:1011-1041. [PMID: 31735090 DOI: 10.1080/14787210.2019.1694905] [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] [Indexed: 12/12/2022]
Abstract
Introduction: In light of the emergence of antibiotic-resistant bacteria, phage (bacteriophage) therapy has been recognized as a potential alternative or addition to antibiotics in Western medicine for use in humans.Areas covered: This review assessed the scientific literature on phage therapy published between 1 January 2007 and 21 October 2019, with a focus on the successes and challenges of this prospective therapeutic.Expert opinion: Efficacy has been shown in animal models and experimental findings suggest promise for the safety of human phagotherapy. Significant challenges remain to be addressed prior to the standardization of phage therapy in the West, including the development of phage-resistant bacteria; the pharmacokinetic complexities of phage; and any potential human immune response incited by phagotherapy.
Collapse
Affiliation(s)
- Katherine M Caflisch
- Department of Molecular Pharmacology and Experimental Therapeutics, Mayo Clinic, Rochester, MN, USA
| | - Gina A Suh
- Division of Infectious Diseases, Department of Medicine, Mayo Clinic, Rochester, MN, USA
| | - Robin Patel
- Division of Infectious Diseases, Department of Medicine, Mayo Clinic, Rochester, MN, USA.,Division of Clinical Microbiology, Department of Laboratory Medicine and Pathology, Mayo Clinic, Rochester, MN, USA
| |
Collapse
|
18
|
Shang X, Nelson DC. Contributions of Net Charge on the PlyC Endolysin CHAP Domain. Antibiotics (Basel) 2019; 8:antibiotics8020070. [PMID: 31142020 PMCID: PMC6628322 DOI: 10.3390/antibiotics8020070] [Citation(s) in RCA: 10] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/29/2019] [Revised: 05/20/2019] [Accepted: 05/25/2019] [Indexed: 12/18/2022] Open
Abstract
Bacteriophage endolysins, enzymes that degrade the bacterial peptidoglycan (PG), have gained an increasing interest as alternative antimicrobial agents, due to their ability to kill antibiotic resistant pathogens efficiently when applied externally as purified proteins. Typical endolysins derived from bacteriophage that infect Gram-positive hosts consist of an N-terminal enzymatically-active domain (EAD) that cleaves covalent bonds in the PG, and a C-terminal cell-binding domain (CBD) that recognizes specific ligands on the surface of the PG. Although CBDs are usually essential for the EADs to access the PG substrate, some EADs possess activity in the absence of CBDs, and a few even display better activity profiles or an extended host spectrum than the full-length endolysin. A current hypothesis suggests a net positive charge on the EAD enables it to reach the negatively charged bacterial surface via ionic interactions in the absence of a CBD. Here, we used the PlyC CHAP domain as a model EAD to further test the hypothesis. We mutated negatively charged surface amino acids of the CHAP domain that are not involved in structured regions to neutral or positively charged amino acids in order to increase the net charge from -3 to a range from +1 to +7. The seven mutant candidates were successfully expressed and purified as soluble proteins. Contrary to the current hypothesis, none of the mutants were more active than wild-type CHAP. Analysis of electrostatic surface potential implies that the surface charge distribution may affect the activity of a positively charged EAD. Thus, we suggest that while charge should continue to be considered for future engineering efforts, it should not be the sole focus of such engineering efforts.
Collapse
Affiliation(s)
- Xiaoran Shang
- Institute for Bioscience and Biotechnology Research, Rockville, MD 20850, USA.
| | - Daniel C Nelson
- Institute for Bioscience and Biotechnology Research, Rockville, MD 20850, USA.
- Department of Veterinary Medicine, University of Maryland, College Park, MD 20742, USA.
| |
Collapse
|