Structure of S35C flavodoxin mutant from Desulfovibrio vulgaris in the semiquinone state.

The crystallographic structure of an engineered flavodoxin mutant from Desulfovihrio vulgaris has been analysed. Site-directed mutagenesis was used to substitute serine 35 with a cysteine to provide a possible covalent linkage. The crystal structure of the semiquinone form of this mutant is similar to the corresponding oxidation state of the wild-type flavodoxin. Analysis of the structural changes reveals the interaction between N(5)H of the flavin and the carhonyl 0 atom of G1y61 to he critical for modulation of the electrochemical properties of the protein. [ABSTRACT FROM AUTHOR]