Characterization of sortase a expression in enterococcus faecalis.

Gram-positive bacteria rely on a family of sorting enzymes called sortases to attach cell surface proteins, often virulence factors, to their peptidoglycan cell wall. Two classes of sortase enzyme exist in Enterococcus faecalis, sortase A (SrtA) and sortase C (SrtC). Understanding these enzymes will provide new insight on sortases as a new target for antimicrobial therapy. This study aims to characterize SrtA, a key contributor to the pathogenicity of E. faecalis. Immunofluorescence microscopy and immunoblotting techniques were employed to determine the expression and localization pattern of SrtA. SrtA was observed on approximately 20% of cells in the planktonic mode of life with specific localization in foci at the division septum. Interestingly, when grown to form biofilms, SrtA was found to be expressed in most, if not all cells. Furthermore, instead of localizing at single foci at the septum, SrtA was distributed at the hemisphere of the biofilm cells, a phenotype completely different as opposed to planktonic cells. We conclude that SrtA expression is highly variable in different modes of life and growth phases.Bachelor of Science in Biological Science