Fig. 2.

Idealized mutants are restricted to the intended register. Formation of intradimer disulfide bonds by (A) AB*^1R and (B) AB*^2R containing 160C (control), 161C (register 2 probe), or 162C (register 1 probe) mutations. (Left, Initial) Proteins were initially heated and reduced and were visualized by Coomassie-stained, nonreducing SDS/PAGE. (Middle, Final) Proteins were then cooled and diluted without reducing agent. The formation of disulfide bonds was assessed by nonreducing SDS/PAGE, which was visualized by Western blot using anti-M1 polyclonal antibodies. (Right, Final) Same as the middle panel, except under reducing conditions.