title: Molecular model of an actin filament capped by a severing protein.
abstract: Gelsolin is a six-domain protein with a wide array of actin regulating activities. Despite the growing body of structural data on this protein, little is known about how it binds F-actin during severing and capping. In this paper we have combined data from X-ray crystallography, NMR, and electron microscopy to develop a model of an actin filament capped by a severing protein. The protein which we have modeled is G1/alpha A1-2, a genetically engineered molecule containing domains from both gelsolin and alpha-actinin. In the capped filament, domains G1 and alpha A1-2 of the hybrid severing protein bind two adjacent monomers along the long-pitch F-actin helix. The distance spanning these domains suggests the need for a flexible linker between them. By analogy, this implies that the gelsolin deletion mutant G1-3 contacts the same two monomers in the capped filament and suggests that the linker between G1 and G2 plays a crucial role in severing and capping.
authors.affiliation: Verna & Marrs McLean Department of Biochemistry, Baylor College of Medicine, Houston, Texas 77030, USA.
authors.forename: A
authors.initials: A
authors.lastname: McGough
authors.forename: M
authors.initials: M
authors.lastname: Way
mesh_terms: D000185:Actinin / Q000737:chemistry* / Q000235:genetics / Q000378:metabolism / Q000648:ultrastructure; D000199:Actins / Q000737:chemistry* / Q000378:metabolism / Q000648:ultrastructure; D000244:Adenosine Diphosphate / Q000378:metabolism; D002118:Calcium / Q000378:metabolism; D003196:Computer Graphics; D018260:Gelsolin / Q000737:chemistry* / Q000235:genetics / Q000378:metabolism / Q000648:ultrastructure; D008854:Microscopy, Electron; D008958:Models, Molecular; D010590:Phalloidine / Q000737:chemistry / Q000378:metabolism; D011485:Protein Binding; D011993:Recombinant Fusion Proteins / Q000737:chemistry / Q000235:genetics / Q000648:ultrastructure
chemical_list: D000199:Actins; D018260:Gelsolin; D011993:Recombinant Fusion Proteins; D000185:Actinin; D010590:Phalloidine; D000244:Adenosine Diphosphate; D002118:Calcium