Phosphotransferase and substrate binding mechanism of the cAMP-dependent protein kinase catalytic subunit from porcine heart as deduced from the 2.0 A structure of the complex with Mn2+ adenylyl imidodiphosphate and inhibitor peptide PKI(5-24).

摘要: The crystal structure of the porcine heart catalytic subunit cAMP-dependent protein kinase in a ternary complex with MgATP analogue MnAMP-PNP and pseudosubstrate inhibitor peptide, PKI(5-24), has been solved at 2.0 A resolution from monoclinic crystals isoform CA. refinement is presently an R factor 0.194 active site molecule well defined. glycine-rich phosphate anchor nucleotide binding fold motif beta ribbon acting as flap conformational flexibility over triphosphate group. glycines seem to be conserved avoid steric clash ATP. known synergistic effects substrate can explained by hydrogen bonds present only complex. Implications for kinetic scheme order are discussed. assumed represent phosphotransfer competent conformation. invariant residue Asp166 proposed base Lys168 stabilize transition state. In some tyrosine kinases functionally replaced Arg displaced two residues primary sequence, suggesting invariance three-dimensional space. supports in-line transfer pentacoordinate state phosphorus very few nuclear movements.