Helix straightening as an activation mechanism in the gelsolin superfamily of actin regulatory proteins.

ABSTRACT: Villin and gelsolin consist of six homologous domains of the gelsolin/cofilin fold (V1-V6 and G1-G6, respectively). Villin differs from gelsolin in possessing at its C terminus an unrelated seventh domain, the villin headpiece. Here, we present the crystal structure of villin domain V6 in an environment in which intact villin would be inactive, in the absence of bound Ca(2+) or phosphorylation. The structure of V6 more closely resembles that of the activated form of G6, which contains one bound Ca(2+), rather than that of the calcium ion-free form of G6 within intact inactive gelsolin. Strikingly apparent is that the long helix in V6 is straight, as found in the activated form of G6, as opposed to the kinked version in inactive gelsolin. Molecular dynamics calculations suggest that the pre

SUBMITTER: Wang H 

PROVIDER: S-EPMC2755850 | biostudies-literature | 2009 Aug

REPOSITORIES: biostudies-literature