Sulfhydryl cross-linking of single LmrA cysteine substitution mutants.

<p>Immunoblotted SDS-polyacrylamide 7.5% gels with 10 μg of membrane protein run in each lane. Lane 1 contains LmrA wild-type (cysteine-less); lanes 2, 3 and 4 contain mutants A433C, M435C and S516C, respectively, cross-linked at 4°C; and lanes 5, 6, and 7, the same mutants cross-linked at 21°C. The different positions for the dimers is due to different cross-linked positions giving rise to dissimilar configurations of the linearised cross-linked dimers and hence alterations in their mobilities. Molecular size positions were run in the lane marked ‘S’. The LmrAe monomer in the lane marked ‘W’ has an apparent molecular mass of 66 kDa.