1mmd
|
TRUNCATED HEAD OF MYOSIN FROM DICTYOSTELIUM DISCOIDEUM COMPLEXED WITH MGADP-BEF3
OverviewOverview
The three-dimensional structures of the truncated myosin head from, Dictyostelium discoideum myosin II complexed with beryllium and aluminum, fluoride and magnesium ADP are reported at 2.0 and 2.6 A resolution, respectively. Crystals of the beryllium fluoride-MgADP complex belong to, space group P2(1)2(1)2 with unit cell parameters of a = 105.3 A, b = 182.6, A, and c = 54.7 A, whereas the crystals of the aluminum fluoride complex, belong to the orthorhombic space group C222(1) with unit cell dimensions, of a = 87.9 A, b = 149.0 A, and c = 153.8 A. Chemical modification was not, necessary to obtain these crystals. These structures reveal the location, of the nucleotide complexes and define the amino acid residues that form, the active site. The tertiary structure of the protein complexed with, MgADP.BeFx is essentially identical to that observed previously in the, three-dimensional model of chicken skeletal muscle myosin subfragment-1 in, which no nucleotide was present. By contrast, the complex with MgADP.AlF4-, exhibits significant domain movements. The structures suggest that the, MgADP.BeFx complex mimics the ATP bound state and the MgADP.AlF4- complex, is an analog of the transition state for hydrolysis. The domain movements, observed in the MgADP.AlF4- complex indicate that myosin undergoes a, conformational change during hydrolysis that is not associated with the, nucleotide binding pocket but rather occurs in the COOH-terminal segment, of the myosin motor domain.
About this StructureAbout this Structure
1MMD is a Single protein structure of sequence from Dictyostelium discoideum with MG, ADP and BEF as ligands. Active as Myosin ATPase, with EC number 3.6.4.1 Full crystallographic information is available from OCA.
ReferenceReference
X-ray structures of the myosin motor domain of Dictyostelium discoideum complexed with MgADP.BeFx and MgADP.AlF4-., Fisher AJ, Smith CA, Thoden JB, Smith R, Sutoh K, Holden HM, Rayment I, Biochemistry. 1995 Jul 18;34(28):8960-72. PMID:7619795
Page seeded by OCA on Tue Nov 20 21:31:43 2007