Insights into the phosphoryl transfer catalyzed by cAMP-dependent protein kinase: an X-ray crystallographic study of complexes with various metals and peptide substrate SP20.

ABSTRACT: X-ray structures of several ternary substrate and product complexes of the catalytic subunit of cAMP-dependent protein kinase (PKAc) have been determined with different bound metal ions. In the PKAc complexes, Mg(2+), Ca(2+), Sr(2+), and Ba(2+) metal ions could bind to the active site and facilitate the phosphoryl transfer reaction. ATP and a substrate peptide (SP20) were modified, and the reaction products ADP and the phosphorylated peptide were found trapped in the enzyme active site. Finally, we determined the structure of a pseudo-Michaelis complex containing Mg(2+), nonhydrolyzable AMP-PCP (β,γ-methyleneadenosine 5'-triphosphate) and SP20. The product structures together with the pseudo-Michaelis complex provide snapshots of different stages of the phosphorylation reaction. Comparison

SUBMITTER: Gerlits O 

PROVIDER: S-EPMC3666212 | biostudies-literature | 2013 May

REPOSITORIES: biostudies-literature