3B). R526 through the 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 main chain carbonyl of R413. The tip with the activation section is stabilized by a hydrogen bond concerning Y454 and E480 from αF. whil… Read More