Fig. 6.

Cross-linking of FAS by dibromopropanone. The SDS–poly-acrylamide gel shows the three new cross-linked species [ii–iv] formed by treatment of the wild-type FAS with dibromopropanone. Species [i] represent residual subunits that have not undergone cross-linking. Molecular masses were determined by mass spectrometry. The identities of the cross-linked species were determined by performing cross-linking on a panel of mutants lacking either the ACP 4-phosphopantetheine or the KS active site cysteine on one or both subunits. The cartoons on the right illustrate the mode of cross-linking, either inter- or intra subunit.