K72

Kinase Glossary: K72

K72 is a key conserved residue in ePK and most PKL kinases. It is part of the VAIK motif in the b3 strand. This lysine hydrogen bonds to the alpha oxygen and the beta phosphate of ATP, stabilizing its negative charge, and also forms a salt bridge with E91. It is one of three residues (along with D166 and D184) whose absence is used to predict pseudokinases. In the Wnk family of kinases, K72 is absent, but a similar lysine is seen close to the G-rich loop and performs the same function. The number 72 is based on the position of this residue in the first PKA kinase crystal.