Role of cation-π interactions in the structural stability of bacterial adhesins

Attachment to host cell surfaces is a crucial step in bacterial infections. This step is mediated by important virulence factors termed adhesins which are protein in nature. Non-covalent interactions play an important role in the structural stability of protein molecules. In the present study, the roles played by cation-π interactions in the adhesion proteins of Gram negative bacilli, Gram negative cocci and Gram positive cocci are systematically analyzed. There are significant differences in the pattern of interactions and environmental preferences like secondary structure, solvent accessibility, and stabilization centers for the amino acid residues which are involved in interactions. Among the cationic residues the role of Arg is significant in Gram negative group, while in the case of Gram positive cocci the contribution from Lys is found to be important. These results might be useful for understanding the stability patterns of adhesins in different groups of pathogenic bacteria.