THE REFINED STRUCTURE OF THE COMPLEX BETWEEN ADENYLATE KINASE FROM BEEF-HEART MITOCHONDRIAL MATRIX AND ITS SUBSTRATE AMP AT 1.85 A RESOLUTION

The crystal structure of the complex between adenylate kinase from bovine mitochondrial matrix and its substrate AMP has been refined at 1.85 Å resolution (1 Å = 0.1 nm). Based on 42,519 independent reflections of better than 10 Å resolution, a final R-factor of 18.9% was obtained with a model obeying standard geometry within 0.016 Å in bond lengths and 3.2 ° in bond angles. There are two enzyme: substrate complexes in the asymmetric unit, each consisting of 226 amino acid residues, one AMP and one sulfate ion. A superposition of the two full-length polypeptides revealed deviations that can be described as small relative movements of three domains. Best superpositions of individual domains yielded a residual overall root-mean-square deviation of 0.3 Å for the backbone atoms and 0.5 Å for the side-chains. The final model contains 381 solvent molecules in the asymmetric unit, 2 × 72 = 144 of which occupy corresponding positions in both complexes. © 1991.