An investigation of the structure and function of antistaphylococcal endolysins using kinetic methods

Authors: FILATOVA, L. YU - Moscow State University; Donovan, David; Becker, Stephen; KABANOV, A.V. - Moscow State University; KLYACHKO, NATALIA - Moscow State University

Submitted to: Moscow University Chemistry Bulletin
Publication Type: Peer Reviewed Journal
Publication Acceptance Date: 2/25/2014
Publication Date: 5/1/2014
Citation: Filatova, L., Donovan, D.M., Becker, S.C., Kabanov, A., Klyachko, N.L. 2014. An investigation of the structure and function of antistaphylococcal endolysins using kinetic methods. Moscow University Chemistry Bulletin. 69(3):107-111.

Interpretive Summary: The use of phage endolysins as alternatives to antibiotics is a relatively new field. The endolysins are enzymes and thus are highly susceptible to environmental conditions required for optimal activity. There are numerous highly homologous enzymes reported in the literature and in order to identify where each might find application a thorough characterization of their activity profile and conditions required to achieve optimal activity is necessary. This work demonstrates that two phage (phi11 and phi80a) endolysins although highly homologous with only one amino acid difference between them, have slightly different activity profiles depending on the environment they are exposed to (pH, temperature, metal ions and reducing agents/EDTA). This work establishes a base-line for the level of activity variability that can be seen with nearly identical endolysins. This study benefits primarily fellow scientists in the field. The enzymes are active against numerous staphylococczal pathogens which in itself indicates a benefit for the farmer, and both animal and human health care workers, but this was known previously. This is the first time a thorough characterization of the enzyme kinetics has been reported contrasting two nearly identical antimicrobial enzymes (single amino acid difference). Most scientists would assume the two enzymes to have virtually identical activity profiles. This work has merit in the fact that it identifies unexpected differences in activity and thus establishes a base-line for predicted variability in activity between related enzymes under the most basic changes in the environment. The differences in activity are in response to small environmental changes which any enzyme might encounter in a normal application and thus raise the awareness of the potential variability in applications available between even highly similar enzymes.

Technical Abstract: Peculiarities of the structures and functions of phage phi11 and phi80a antistaphylococcal endolysins were investigated by kinetic measurements. In spite of the high level of homology in their primary structures, both enzymes possess some differences in their optimal conditions for functioning. As has been shown, phage phi11 endolysin is activated by metal cations (Ca2+, Mg2+). Sulfhydril groups can play an important role in catalytic processes for both phage phi11 and phi80a endolysins. These findings help to elucidate potential applications where these highly specialized proteins might serve as antimicrobials for human and animal diseases.