title: Structural basis for the allosteric interference of myosin function by reactive thiol region mutations G680A and G680V.
abstract: The cold-sensitive single-residue mutation of glycine 680 in the reactive thiol region of Dictyostelium discoideum myosin-2 or the corresponding conserved glycine in other myosin isoforms has been reported to interfere with motor function. Here we present the x-ray structures of myosin motor domain mutants G680A in the absence and presence of nucleotide as well as the apo structure of mutant G680V. Our results show that the Gly-680 mutations lead to uncoupling of the reactive thiol region from the surrounding structural elements. Structural and functional data indicate that the mutations induce the preferential population of a state that resembles the ADP-bound state. Moreover, the Gly-680 mutants display greatly reduced dynamic properties, which appear to be related to the recovery of myosin motor function at elevated temperatures.
authors.affiliation: Institut für Biophysikalische Chemie, Medizinische Hochschule Hannover, Carl-Neuberg-Strasse 1, 30625 Hannover, Germany.
authors.forename: Matthias
authors.initials: M
authors.lastname: Preller
authors.forename: Stefanie
authors.initials: S
authors.lastname: Bauer
authors.forename: Nancy
authors.initials: N
authors.lastname: Adamek
authors.forename: Setsuko
authors.initials: S
authors.lastname: Fujita-Becker
authors.forename: Roman
authors.initials: R
authors.lastname: Fedorov
authors.forename: Michael A
authors.initials: MA
authors.lastname: Geeves
authors.forename: Dietmar J
authors.initials: DJ
authors.lastname: Manstein
mesh_terms: D000244:Adenosine Diphosphate / Q000737:chemistry; D000495:Allosteric Site; D001665:Binding Sites; D003080:Cold Temperature; D018360:Crystallography, X-Ray / Q000379:methods; D004023:Dictyostelium / Q000378:metabolism*; D007700:Kinetics; D008958:Models, Molecular; D016296:Mutagenesis; D009154:Mutation; D009218:Myosins / Q000737:chemistry*; D025341:Principal Component Analysis; D013438:Sulfhydryl Compounds / Q000737:chemistry*; D013696:Temperature; D013816:Thermodynamics
chemical_list: D013438:Sulfhydryl Compounds; D000244:Adenosine Diphosphate; D009218:Myosins