7.4.2.5 | to 1.9 A resolution. Structure represents an intermediate state during the transition of the clamp from an open to a closed conformation. Closure of the clamp occurs in two phases, an initial movement of polypeptide cross-linking domain PPXD, helical scaffold domain HSD, and helical wing domain HWD as a unit, followed by a movement of PPXD alone toward nucleotide-binding domain NBD2. The substrate associates with the back of the clamp by dynamic hydrogen bonding and the clamp is laterally closed by a conserved loop of the PPXD |
734488 |