Structural Variations in Protein Superfamilies: Actin and Tubulin |
| |
Authors: | Richard H Wade Isabel Garcia-Saez Frank Kozielski |
| |
Institution: | (1) Institut de Biologie Structurale, 41 rue Jules Horowitz, 38027 Grenoble Cedex 1, France;(2) The Beatson Institute for Cancer Research, Garscube Estate, Switchback Road, Bearsden, Glasgow, G61 1BD, Scotland, UK |
| |
Abstract: | Structures of homologous proteins are usually conserved during evolution, as are critical active site residues. This is the
case for actin and tubulin, the two most important cytoskeleton proteins in eukaryotes. Actins and their related proteins
(Arps) constitute a large superfamily whereas the tubulin family has fewer members. Unaligned sequences of these two protein
families were analysed by searching for short groups of family-specific amino acid residues, that we call motifs, and by counting
the number of residues from one motif to the next. For each sequence, the set of motif-to-motif residue counts forms a subfamily-specific
pattern (landmark pattern) allowing actin and tubulin superfamily members to be identified and sorted into subfamilies. The
differences between patterns of individual subfamilies are due to inserts and deletions (indels). Inserts appear to have arisen
at an early stage in eukaryote evolution as suggested by the small but consistent kingdom-dependent differences found within
many Arp subfamilies and in γ-tubulins. Inserts tend to be in surface loops where they can influence subfamily-specific function
without disturbing the core structure of the protein. The relatively few indels found for tubulins have similar positions
to established results, whereas we find many previously unreported indel positions and lengths for the metazoan Arps. |
| |
Keywords: | Structure variation in protein families Actin Tubulin |
本文献已被 SpringerLink 等数据库收录! |
|