title: Structural studies on the ribbon-to-helix transition in profilin: actin crystals.
abstract: Knowledge of the structure of actin in its various conformational states is important for understanding the diverse motile activities carried out by eukaryotic cells. Profilin:actin crystals provide a unique system for studying conformational states of actin, because they exhibit a high degree of polymorphism in response to environmental conditions while maintaining crystalline order. A preliminary comparison of two states of profilin:beta-actin crystals shows that crystal polymorphism involves movements of actin subdomains at hinge points homologous to those found in hexokinase, a protein whose polypeptide fold is related to actin. The homology of the hinge points in actin to those in hexokinase suggests that actin subdomain movements in profilin:beta-actin crystals have functional significance. We discuss how these movements could be related to structural transitions between states of filamentous actin in muscle contraction.
authors.affiliation: Department of Chemistry, Henry H. Hoyt Laboratory, Princeton University, New Jersey 08544, USA.
authors.forename: C E
authors.initials: CE
authors.lastname: Schutt
authors.forename: M D
authors.initials: MD
authors.lastname: Rozycki
authors.forename: J K
authors.initials: JK
authors.lastname: Chik
authors.forename: U
authors.initials: U
authors.lastname: Lindberg
mesh_terms: D000199:Actins / Q000737:chemistry* / Q000502:physiology; D000205:Actomyosin / Q000737:chemistry / Q000502:physiology; D000818:Animals; D055592:Biophysical Phenomena; D001703:Biophysics; D002417:Cattle; D003285:Contractile Proteins; D003460:Crystallization; D008840:Microfilament Proteins / Q000737:chemistry* / Q000502:physiology; D008954:Models, Biological; D008958:Models, Molecular; D015394:Molecular Structure; D009119:Muscle Contraction / Q000502:physiology; D051304:Profilins; D011487:Protein Conformation; D017433:Protein Structure, Secondary
chemical_list: D000199:Actins; D003285:Contractile Proteins; D008840:Microfilament Proteins; D051304:Profilins; D000205:Actomyosin