cpRAS: a novel circularly permuted RAS-like GTPase domain with a highly scattered phylogenetic distribution

Marek Elias¹ and Marian Novotny²

¹Charles University in Prague, Faculty of Science, Department of Botany, Benatska 2, 128 01 Prague 2, Czech Republic

²Charles University in Prague, Faculty of Science, Department of Cell Biology Vinicna 7, 128 44 Prague 2, Czech Republic

author email corresponding author email

Biology Direct 2008, 3:21doi:10.1186/1745-6150-3-21


Published:	29 May 2008

Abstract

A recent systematic survey suggested that the YRG (or YawG/YlqF) family with the G4-G5-G1-G2-G3 order of the conserved GTPase motifs represents the only possible circularly permuted variation of the canonical GTPase structure. Here we show that a different circularly permuted GTPase domain actually does exist, conforming to the pattern G3-G4-G5-G1-G2. The domain, dubbed cpRAS, is a variant of RAS family GTPases and occurs in two types of larger proteins, either inserted into a region homologous to a bacterial group of proteins classified as COG2373 and potentially related to the alpha-2-macroglobulin family (so far a single protein in Dictyostelium) or in combination with a von Willebrand factor type A (VWA) domain. For the latter protein type, which was found in a few metazoans and several distantly related protists, existence in the common ancestor of opisthokonts, Amoebozoa and excavates followed by at least eight independent losses may be inferred. Our findings thus bring further evidence for the importance of parallel reduction of ancestral complexity in the eukaryotic evolution.

Reviewers

This article was reviewed by Lakshminarayan Iyer and Fyodor Kondrashov. For the full reviews, please go to the Reviewers' comments section.