TABLE 2

Distances of residues in the models that have previously been shown to be cross-linked in double cysteine mutants TM helix a and TM helix b denote the pairs of putative transmembrane α-helices in which cross-links between two cysteines introduced at residues a and b could be obtained

The source reference is given in the rightmost column. To allow a more convenient identification of the mutated residues, they are denoted with their original (nonmutated) three-letter amino acid code followed by the position in the primary sequence. All distances are minimum distances and are measured between the C_α atoms of the specified residues. In instances in which more than one pair of residues has been cross-linked, the superscripts 1 to 4 are used to identify these pairs, and the minimum and maximum distances are given. In the case of the triple-cysteine mutants (Stenham et al., 2003), the minimum distance is given.