The VCBS superfamily forms a third supercluster of b-propellers that includes tachylectin and integrins

Abstract

Motivation: b-Propellers are found in great variety across all kingdoms of life. They assume many cellular roles, primarily as scaffolds for macromolecular interactions and catalysis. Despite their diversity, most b-propeller families clearly originated by amplification from the same ancient peptide-the 'blade'. In cluster analyses, b-propellers of the WD40 superfamily always formed the largest group, to which some important families, such as the a-integrin, Asp-box and glycoside hydrolase b-propellers connected weakly. Motivated by the dramatic growth of sequence databases we revisited these connections, with a special focus on VCBS-like b-propellers, which have not been analysed for their evolutionary relationships so far. Results: We found that VCBS-like form a supercluster with integrin-like b-propellers and tachylectins, clearly delimited from the superclusters formed by WD40 and Asp-Box b-propellers. Connections between the three superclusters are made mainly through PQQ-like b-propeller. Our results present a new, greatly expanded view of the b-propeller classification landscape.