|Foster Frey, Juli|
Submitted to: Applied and Environmental Microbiology
Publication Type: Peer Reviewed Journal
Publication Acceptance Date: 6/14/2012
Publication Date: 4/1/2013
Citation: Abaev, I., Foster Frey, J.A., Korobova, O., Shishkova, N., Kopylov, P., Pyramchuk, S., Schmelcher, M., Becker, S.C., Donovan, D.M. 2013. Staphylococcal phage 2638a endolysin is lytic for Staphylococcus aureus and harbors an inter-lytic-domain cryptic translational start site. Applied and Environmental Microbiology. 97(8):3449-3456. Interpretive Summary: Brief explanation of the reason for, accomplishment of, and significance of the research in language intelligible to the general public. A. Problem— Mastitis causes the dairy industry in the USA over $2 billion in losses every year. Staphylococcus aureus is a notorious pathogen for both humans and animals, causing up to 40% of the bovine mastitis in the USA. There is a need for novel antimicrobials due to the high incidence of resistance development and multi-drug resistant strains of this pathogen. B. Accomplishment— This manuscript describes a staphylococcal phage endolysin (phage 2638A) that has staphylolytic properties when purified and exposed to S. aureus cells. The lytic activity requires a SH3b cell wall binding domain, and is largely dependent on the Amidase domain. There are very few staphylolytic amidase domains shown to have high activity and thus this protein is of importance to labs and searching for novel antimicrobial lytic domains. C. Contribution of Accomplishment to Solving the Problem-- This fusion antimicrobial is a candidate for treating bovine mastitis and other staphylococcal infections and because it is active in a fusion setting might be amenable for use in other potentially more active fusion protein antimicrobials.
Technical Abstract: Staphylococcus aureus, a notorious pathogen with a propensity for developing resistance to virtually all antibiotics. Staphylococcal phage 2638A endolysin is a peptidoglycan hydrolase that is lytic for Staphylococcus aureus when exposed externally, making it a new candidate antimicrobial. It shares a common SH3b containing peptidoglycan hydrolase organization with more than 40 other reported staphylococcal peptidoglycan hydrolases. There is an an N-terminal cysteine, histidine-dependent amidohydrolases/peptidases (CHAP) endopeptidase domain, a mid-protein amidase 2 domain (N-acetylmuramoyl-L-alanine amidase and a C-terminal SH3b cell wall binding domain (CHAP-amidase-SH3b). It is the first lysin reported with a cryptic translational start site in the inter-lytic-domain region between the CHAP and amidase domains. The amidase domain appears to confer most of the lytic activity and requires the full SH3b domain for maximal activity. Although it is common for one domain to demonstrate a dominant activity over the other, the 2638A endolysin is the first in this class reported to have a high activity amidase domain [dominant over the N-terminal CHAP domain]. The high activity amidase domain is an important finding in this labs quest for high activity staphylolytic domains with novel sites of action for producing triple-acting fusion antimicrobials that are designed to be refractory to resistance development.