THE BEST SIDE OF PKRRATING

3B). R526 with the loop amongst αJ and αI anchors the C-terminal portion of the activation loop by forming a salt bridge with E458 at The bottom of αEF. Q459 stabilizes the HRD motif by a hydrogen bond to the primary chain carbonyl of R413. The suggestion from the activation phase is stabilized by a hydrogen bond between Y454 and E480 from αF.