The crystal structure of the complex between adenylate kinase from bovine
mitochondrial matrix and its substrate AMP has been refined at 1.85 A resolution
(1 A = 0.1 nm). Based on 42,519 independent reflections of better than 10 A
resolution, a final R-factor of 18.9% was obtained with a model obeying standard
geometry within 0.016 A in bond lengths and 3.2 degrees 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 A for the backbone
atoms and 0.5 A for the sidechains. The final model contains 381 solvent
molecules in the asymmetric unit, 2 x 72 = 144 of which occupy corresponding
positions in both complexes.
