(a) Overall structure of PDB entry 3vqh
: a ternary complex of the catalytic subunit α of protein kinase A (PKA; white), the peptidic pseudosubstrate `protein kinase inhibitor' (PKI; grey) and the ATP-competitive inhibitor H-89 (yellow). (b) B/temperature factors of the H-89 conformers in the structure 3vqh
plotted as spheres on the respective atoms. The values are indicated for selected atoms. (c) Binding environment of the H-89 conformers in the ATP pocket of PKA in structure 3vqh
. Residues Val123, Glu127 and Asn171 form hydrogen bonds to the ligands; the bromine moieties pack against hydrophobic atoms from the side chains of Phe54 and Lys174 and some main-chain atoms of the glycine-rich loop. The inner surface of the ATP pocket is represented in red (maximum distance of 2 Å from the inhibitor molecule).