FIGURE 1.

Schematic depictions of the E. coli MscL emphasizing the pore domain and specific residues that were targeted for substitutions. The upper panel shows a model for the closed MscL structure (11) based upon the crystal structure (10). The residues investigated by this study are highlighted in blue and shown in a cpk format. A side view (left), a single subunit of the pentameric complex (center), and top view are shown. The bottom panel presents an idealized helical wheel (left) and net (right) of the E. coli MscL first transmembrane domain. The residues encircled in the helical net were identified in the in vivo SCAM assay (17) as described in text. The residues within the shaded region were accessible to MTSET only upon channel gating by osmotic downshock. The residues that are further investigated by patch clamp in this study are colored dependent on whether the MTSET was accessible without (blue) or with (green) channel gating.