Figure 6.

Protection by l-glutamate against maleimide labeling. Western blot analysis of purified mutants S129C, S269C, and E271C labeled with biotin maleimide in whole cells (A and B) and inside-out membrane vesicles (C and D) in the absence (−) or presence (+) of 2 mM l-glutamate (L) or d-glutamate (D). Western blots were decorated with streptavidin coupled to alkaline phosphatase to detect biotinylated proteins (A and C) and antibodies against the His-tag to compare the amounts of protein (B and D).