Cloning, sequencing and overexpression of the Desulfovibrio gigas ferredoxin gene in E. coli

We have cloned the gene encoding Desulfovibrio gigas ferredoxin using a photodigoxigenin-labelled probe synthesized with the polymerase chain reaction. The DNA sequence of the gene predicts a polypeptide of 58 residues after removal of the initial formyl methionine (polypeptide Mr = 6,276). The ferredoxin gene was expressed in aerobically grown E. coli behind the lac promoter of pUC18 resulting in a high level of ferredoxin expression which comprises about 10% of the total cell protein. EPR analysis of recombinant ferredoxin revealed the presence of a [3Fe-4S] cluster which is characteristic of native D. gigas ferredoxin II.