Year: 2014
Type: dissertation
Abstract: Pseudomonas aeruginosa is an opportunistic, gram-negative pathogen that is involved in a variety of infections. The bacterium secretes and chemically modifies alginate to form a protective biofilm matrix. One protein implicated in the O-acetylation of alginate is AlgJ. In this study, we have successfully crystallized AlgJ and determined its structure to 1.83Å. The structure reveals that AlgJ is a SGNH hydrolase-like protein. AlgJ possesses a Ser-Asp-His catalytic triad which suggests that AlgJ is catalytically active. The structure of AlgJ demonstrated that the previously identified conserved residues of the AlgJ signature motifs form a local network with the proposed catalytic triad and are important for alginate O-acetylation in vivo. We have assayed the proposed Ser-Asp-His catalytic triad in vitro and observed impairment in acetyl esterase activity. In vitro binding studies demonstrated that AlgJ was unable to bind polymannuronate and that was it not capable of O-acetylating the polymer.
Source: TSpace (University of Toronto)
Author: Tyler Ricer
Language: English
Subfield: Molecular Biology
Domain: Life Sciences
Open Access status: green
OpenAlex ID: W3201045841