FIG. 4.

Rates of penetration of various sugars through the OmpG channel. Proteoliposomes containing OmpG extract were made as described in Material and Methods, and portions of the suspension were diluted into iso-osmotic solutions of sugars to determine the rates of osmotic swelling of the vesicles. The rates were normalized to the swelling rate in l-arabinose, which was taken as 100%. The sugars used (and, in parentheses, their molecular weights) were l-arabinose (150), d-glucose (180), N-acetylglucosamine (221), 2,3-diacetamido-2,3-dideoxy-d-glucose (262), lactose (342), sucrose (342), and maltose (342). As a control, proteoliposomes containing OmpC extract were used.