Fig. 7.

Mutation of negative residues on the SBD of BiP can affect interdomain communication and ATP hydrolysis. (A) Recombinant proteins corresponding to wild-type BiP, three single-point mutants in the SBD, and a TM in which all three residues were combined were incubated with a fusion protein corresponding to ERdj3 J domain and GST. Bound material was subjected to SDS/PAGE analysis and detected by Coomassie blue staining. (B) The indicated recombinant BiP proteins were incubated with ATP, ADP, or no nucleotide and treated with proteinase K as described in Fig. 2. (C) Recombinant BiP proteins were analyzed for ATPase activity alone (−), with ERdj3 (J), with peptide C (C), and with the two together (J/C).