FIGURE 2.

Sec22 SNARE motif cysteine-derivatives shift to higher molecular weight species under oxidizing conditions. Washed semi-intact cells expressing the indicated cysteine derivatives of Sec22 in CBY773 were incubated in the absence (−) or presence (+) of 0.2 mm Cu²⁺/phen as described under “Experimental Procedures.” After 15 min under oxidizing conditions, the reactions were terminated with sample buffer (containing NEM) and incubated at 70 °C for 5 min. Proteins were resolved by nonreducing SDS-PAGE (10%) and immunoblotted with anti-Sec22. A solid diamond indicates the position of the Sec22 cross-linked species, whereas a solid arrowhead indicates the position of wild-type Sec22.