About pkrrating
3B). R526 from your loop in between αJ and αI anchors the C-terminal part of the activation loop by forming a salt bridge with E458 at the base of αEF. Q459 stabilizes the HRD motif by a hydrogen bond to the principle chain carbonyl of R413. The tip of your activation segment is stabilized by a hydrogen bond between Y454 and E480 from αfile. fr