Structural and Functional Analysis of Listeria Adhesion Protein

Abstract

Listera monocytogenes (Lm) is a gram-positive opportunistic foodborne pathogen. It is responsible for the disease listeriosis, which though rare, causes high morbidity and mortality. The pathogen targets the intestine for systemic entry. Lm uses several membrane proteins to breach the intestinal barrier and to translocate for systemic distribution. Additionally, the pathogen utilizes a normally cytosolic protein for translocation: bifunctional acetaldehyde alcohol dehydrogenase, which moonlights as Listeria adhesion protein (LAP). LAP has been reported to interact with mitochondrial heat shock protein 60 (Hsp60) presented on intestinal epithelial cells. The interaction allows for paracellular translocation, avoiding intracellular host immunity. LAP was cloned, produced and purified for downstream experimentation. The purified protein was characterized with enzyme activity assays and electron microscopy. The acetaldehyde dehydrogenase and alcohol dehydrogenase domains of LAP have Vmax values of 0.56 mM.min-1 and 1.17 mM.min-1 respectively. LAP was also found to oligomerise into filaments potentially needed for activity.