CLONING, SEQUENCING AND OVEREXPRESSION OF THE DESULFOVIBRIO-GIGAS FERREDOXIN GENE IN ESCHERICHIA-COLI

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