Fig 7.

Mild reduction (preferentially at low pH) induces 19-kDa GP Ecto, but not GPΔ Ecto, to bind to liposomes; the F535R mutant Ecto is impaired in liposome binding in response to mild reduction. (A) GPΔ Ecto and 19-kDa GP Ecto were incubated with liposomes and the indicated concentration of TCEP for 10 min at pH 5.5 and 37°C, and liposome binding was assessed as described in the legend to Fig. 1. Data are the averages from duplicate samples. (B) The 19-kDa GP Ecto was incubated with liposomes and the indicated concentration of TCEP for 10 min at 37°C at pH 7.5 or pH 5.5, and liposome binding was assessed as for panel A. Data are the averages of duplicate samples. Similar results were observed in a second experiment. (C) Equivalent amounts of WT and F535R mutant 19-kDa Ecto proteins were incubated with liposomes, treated with 2.5 mM TCEP at 37°C at pH 7.5 or 5.5 as described above, and then analyzed for 19-kDa GP binding as described in the legend to Fig. 5B. Data are from one experiment performed in triplicate. Error bars indicate SD.