|KOROBOVA, OLGA - State Research Center For Applied Microbiology And Biotechnology|
|SCHISCHKOVA, NINA - State Research Center For Applied Microbiology And Biotechnology|
|KOPYLOV, PAVEL - State Research Center For Applied Microbiology And Biotechnology|
|ABAEV, IGOR - State Research Center For Applied Microbiology And Biotechnology|
Submitted to: FEMS Microbiology Letters
Publication Type: Peer Reviewed Journal
Publication Acceptance Date: 11/4/2014
Publication Date: 12/4/2014
Citation: Becker, S.C., Korobova, O., Schischkova, N., Kopylov, P., Donovan, D.M., Abaev, I. 2014. Lytic activity of the staphylolytic Twort phage endolysin CHAP domain is enhanced by the SH3b cell wall binding domain. FEMS Microbiology Letters. 362(1):1-8.
Interpretive Summary: There is a need for antimicrobial treatments to cure Staphylococcus aureus infections. Staphylococci are notoriously prone to antibiotic resistance development, thus novel antimicrobials that avoid resistance development are much needed. A novel antimicrobial protein derived from a virus that infects bacteria has been tested and shown to reduce or eradicate staphylococcal bacteria in the lab. These viral proteins have been shown to be highly refractory to resistance development. Deletions of some regions of this protein make it a more effective antimicrobial agent than the parental protein. The identification of a novel antimicrobial agent that is functional to cure Staphylococcus aureus bacteria is the first step required prior to commercialization of such an agent, for the eventual use by health care workers worldwide. This finding opens the door to testing an optimal construct of this protein in animal models.
Technical Abstract: Increases in the prevalence of antibiotic resistant strains of Staphylococcus (S.) aureus have elicited efforts to develop novel antimicrobials to treat these drug-resistant pathogens. One potential treatment repurposes the lytic enzymes produced by bacteriophages as antimicrobials. The phage Twort endolysin (PlyTW) harbors three domains, a cysteine histidine dependent amidohydrolases /peptidase domain (CHAP), an amidase-2 domain, and a SH3b-5 cell wall binding domain (CBD). Our results indicate that the CHAP domain alone is necessary and sufficient for lysis of live S. aureus, while the amidase-2 domain is insufficient for cell lysis when provided alone. Loss of the CBD results in ~10X reduction of enzymatic activity in both turbidity reduction and plate lysis assays compared to the full length protein. Deletion of the amidase-2 domain resulted in a protein (PlyTW '172-373) with lytic activity that exceeded the activity of the full length construct in both the turbidity reduction and plate lysis assays. Addition of Ca2+ enhanced the turbidity reduction activity of both the full length protein and truncation constructs harboring the CHAP domain. Chelation by addition of EDTA or the addition of zinc inhibited the activity of all PlyTW constructs.