FIG. 3.

SDS-PAGE analysis of the recombinant proteins. C-terminally His-tagged H1, H2, and L proteins were expressed in BL21(DE3) in the absence and presence of lipoic acid, as indicated. The recombinant proteins were then purified on a nickel-nitrilotriacetic acid-agarose column, analyzed by 15% SDS-PAGE, and stained with Coomassie blue. Lanes 1 and 3 and lanes 2 and 4 represent H1 and H2 proteins purified from bacterial cultures grown in absence and presence of lipoic acid, respectively. Lane 5 represents purified L protein. UL and L represent unlipoylated and lipoylated forms of the H proteins, respectively.