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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] [What about the content of this article? (0)] [Affiliation(s)] [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.
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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
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Bowe BK, Wentz TG, Gregg BM, Tepp WH, Schill KM, Sharma S, Pellett S. Genomic Diversity, Competition, and Toxin Production by Group I and II Clostridium botulinum Strains Used in Food Challenge Studies. Microorganisms 2022; 10:microorganisms10101895. [PMID: 36296172 PMCID: PMC9611418 DOI: 10.3390/microorganisms10101895] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/26/2022] [Revised: 09/16/2022] [Accepted: 09/17/2022] [Indexed: 11/16/2022] Open
Abstract
Botulinum neurotoxins (BoNTs) produced by the bacteria Clostridium botulinum are the causative agent of human and animal botulism, a rare but serious and potentially deadly intoxication. Foodborne botulism is caused by the consumption of foods containing BoNTs, which results from contamination of foods with C. botulinum spores and toxin production by the bacteria during growth within the food. Validation of the safety of food products is essential in preventing foodborne botulism, however, limited guidance and standards exist for the selection of strains used in C. botulinum food challenge studies. Sequencing and genomics studies have revealed that C. botulinum is a large, diverse, and polyphyletic species, with physiologic and growth characteristics studied only in a few representatives. Little is known about potential growth competition or effects on toxin production between C. botulinum strains. In this study, we investigated an applied cocktail of ten C. botulinum strains, seven Group I and three Group II. Whole genome SNP alignments revealed that this strain cocktail encompasses the major clades of the Group I and II C. botulinum species. While growth competition appears to exist between several of the strains, the cocktail as a whole resulted in high levels of BoNT production.
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Affiliation(s)
- Brooke Kathryn Bowe
- Department of Bacteriology, University of Wisconsin-Madison, 1550 Linden Dr, Madison, WI 53706, USA
- Food Research Institute, University of Wisconsin-Madison, 1550 Linden Dr, Madison, WI 53706, USA
| | - Travis Gwynn Wentz
- Department of Bacteriology, University of Wisconsin-Madison, 1550 Linden Dr, Madison, WI 53706, USA
- Microbiology Doctoral Training Program, University of Wisconsin-Madison, 1550 Linden Dr, Madison, WI 53706, USA
| | - Brieana Marie Gregg
- Department of Bacteriology, University of Wisconsin-Madison, 1550 Linden Dr, Madison, WI 53706, USA
| | - William Howard Tepp
- Department of Bacteriology, University of Wisconsin-Madison, 1550 Linden Dr, Madison, WI 53706, USA
| | - Kristin Marie Schill
- Food Research Institute, University of Wisconsin-Madison, 1550 Linden Dr, Madison, WI 53706, USA
| | - Shashi Sharma
- Division of Microbiology, Center for Food Safety and Applied Nutrition, Food and Drug Administration, College Park, MD 20740, USA
| | - Sabine Pellett
- Department of Bacteriology, University of Wisconsin-Madison, 1550 Linden Dr, Madison, WI 53706, USA
- Food Research Institute, University of Wisconsin-Madison, 1550 Linden Dr, Madison, WI 53706, USA
- Correspondence:
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Zhang Z, Douillard FP, Korkeala H, Lindström M. Specific Isolation of Clostridium botulinum Group I Cells by Phage Lysin Cell Wall Binding Domain with the Aid of S-Layer Disruption. Int J Mol Sci 2022; 23:8391. [PMID: 35955526 PMCID: PMC9368847 DOI: 10.3390/ijms23158391] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [What about the content of this article? (0)] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/24/2022] [Revised: 07/25/2022] [Accepted: 07/26/2022] [Indexed: 02/05/2023] Open
Abstract
Clostridium botulinum is a notorious pathogen that raises health and food safety concerns by producing the potent botulinum neurotoxin and causing botulism, a potentially fatal neuroparalytic disease in humans and animals. Efficient methods for the identification and isolation of C. botulinum are warranted for laboratory diagnostics of botulism and for food safety risk assessment. The cell wall binding domains (CBD) of phage lysins are recognized by their high specificity and affinity to distinct types of bacteria, which makes them promising for the development of diagnostic tools. We previously identified CBO1751, which is the first antibotulinal phage lysin showing a lytic activity against C. botulinum Group I. In this work, we assessed the host specificity of the CBD of CBO1751 and tested its feasibility as a probe for the specific isolation of C. botulinum Group I strains. We show that the CBO1751 CBD specifically binds to C. botulinum Group I sensu lato (including C. sporogenes) strains. We also demonstrate that some C. botulinum Group I strains possess an S-layer, the disruption of which by an acid glycine treatment is required for efficient binding of the CBO1751 CBD to the cells of these strains. We further developed CBO1751 CBD-based methods using flow cytometry and magnetic separation to specifically isolate viable cells of C. botulinum Group I. These methods present potential for applications in diagnostics and risk assessment in order to control the botulism hazard.
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Yuan Y, Li Q, Zhang S, Gu J, Huang G, Qi Q, Lu X. Enhancing thermal stability and lytic activity of phage lysin PlyAB1 from Acinetobacter baumannii. Biotechnol Bioeng 2022; 119:2731-2742. [PMID: 35859248 DOI: 10.1002/bit.28187] [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: 04/05/2022] [Revised: 07/12/2022] [Accepted: 07/17/2022] [Indexed: 11/11/2022]
Abstract
With the increasingly serious drug resistance of Acinetobacter baumannii, it is urgent to find new antibacterial drugs. Phage lysin PlyAB1 has a bactericidal effect on drug-resistant Acinetobacter baumannii, which has the potential to replace antibiotics to fight infection caused by Acinetobacter baumannii. However, its application is limited by its thermal stability and lytic activity. To solve these problems, molecular dynamics (MD) simulations combined with Hotspot wizard 3.0 were used to identify key residue sites affecting thermal stability, and evolutionary analysis combined with multiple sequence alignment was used to identify key residue sites affecting lytic activity. Four single-point variants with significantly increased thermal stability and four single-point variants with significantly lytic activity were obtained, respectively. Furthermore, by superimposing mutations, we obtained three double-point variants G100Q/K69R, G100R/K69R, and G100K/K69R with significantly improved thermal stability and improved lytic activity. At 45℃, the lytic activity and half-life of the optimal variant G100Q/K69R were 1.51 folds and 24 folds higher than those of the wild PlyAB1, respectively. These results deepen our understanding of the structure and function of phage lysin and contribute to the application of phage lysin in antibiotic substitution. This article is protected by copyright. All rights reserved.
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Affiliation(s)
- Yingbo Yuan
- State Key Laboratory of Microbial Technology, Shandong University, Qingdao, 266237, China
| | - Qingbin Li
- State Key Laboratory of Microbial Technology, Shandong University, Qingdao, 266237, China
| | - Shuhang Zhang
- State Key Laboratory of Microbial Technology, Shandong University, Qingdao, 266237, China
| | - Jinhong Gu
- State Key Laboratory of Microbial Technology, Shandong University, Qingdao, 266237, China
| | - Guangtao Huang
- Department of Burn and Plastic Surgery, Shenzhen Institute of Translational Medicine, The First Affiliated Hospital of Shenzhen University, Shenzhen Second People's Hospital, Shenzhen, 518035, China
| | - Qingsheng Qi
- State Key Laboratory of Microbial Technology, Shandong University, Qingdao, 266237, China
| | - Xuemei Lu
- State Key Laboratory of Microbial Technology, Shandong University, Qingdao, 266237, China
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