Structural and functional analysis of seeligeriolysin O by homology modeling

Abstract

Seeligeriolysin O (LSO) is a cholesterol-dependant cytolysin of Listeria seeligeri. These toxins are produced by various species of Gram-positive bacteria, including members of the genera Streptococcus, Clostridium, and Listeria. Apart from the cytolytic, LSO has been reported to perform cytokine-inducing activity as well. The present study deals with the prediction of three dimensional model, as well as structural and functional analysis of Seeligeriolysin O. MODELLER9 v8 was used for building the homology model. These predicted 3-dimensional models were evaluated with ProSa and PROCHECK software, and the best 3-dimensional models were selected. Multiple alignment was performed with CLUSTALX. Based on the similarity of predicted three dimensional structure of seeligeriolysin O with perfringolysin O, the seeligeriolysin might have similar structure and function with the later. The predicted three dimensional model of seeligeriolysin O had extended rod shaped structure, having ample beta sheets arranged in four domains. The C-terminal region of seeligeriolysin O might have function similar to perfringolysin O. It has been predicted that seeligeriolysin O insertion occurs more readily in an environment having loosely packed lipid.

Key words: Bacterial toxins, tryptophan, Perfringolysin, Listeria seeligeri, cholesterol-dependant cytolysins and domain 4, target protein, template protein.