Fig. 5.

Surface accessibility of VirB9 Cys substitution mutations and FLAG epitope tagged VirB9 derivatives. (A) Intact cells (Upper) and spheroplasts (Lower) were reacted with anti-FLAG antibodies and examined by immunofluorescence microscopy. Strains: B9, PC1009 with pBLC373 producing native VirB9; 216 & 226, PC1009 producing VirB9_FL derivatives with FLAG epitope at these residues. (B) (Upper) Intact cells were incubated with the Cys reactive reagent MPB with (+) or without (-) preblocking with AMS. (Lower) Intact cells were untreated (-) or treated (+) with mPEG-maleimide (mPEG) (5 kDa). Strains: ΔB9, PC1009; ΔB9(B9), PC1009(pBLC373) producing native VirB9; PC1009 with pBLC373 derivatives carrying Cys substitutions at positions indicated.