FIG. 3.

Sucrose gradient centrifugation shows preferential association of TraC with the inner membrane. Membranes from strains FM433/pKM101 and FM433 were subjected to centrifugation through isopycnic sucrose gradients, and fractions (1 through 16) were collected from the top of the gradient. Inner membrane-containing fractions were identified by NADH oxidase activity detected in fractions 1 through 5. (A) SDS-PAGE and Coomassie staining identified porins in the outer membrane-containing fractions. (B and C) Western blot analysis with TraC-specific antiserum after SDS-PAGE of fractions from FM433/pKM101 (B) and FM433 (C). The arrowhead indicates porins of the outer membrane, and the arrow indicates TraC.