Cloning and expression of the ferredoxin gene from extremely halophilic archaeon Haloarcula japonica strain TR-1

The gene encoding a ferredoxin (Fd) from Haloarcula japonica strain TR-1 wa s cloned and sequenced. Sequence analysis of the cloned Ha. japonica Fd gen e revealed that the structural gene consisted of an open reading frame of 3 87 nucleotides encoding 129 amino acids. The deduced amino acid sequence of Ha. japonica Fd showed 84 to 98% identity with corresponding sequences in other extremely halophilic archaea. The Ha. japonica Fd gene was inserted i nto the shuttle vector pWL102 and used to transform Ha. japonica. Ha. japon ica Fd could then be produced as a fusion with His.Tag (6xHis) in Ha. japon ica host cells. The absorption and ESR spectra of the Fd/His.Tag fusion pro tein revealed the presence of a [2Fe-2S] cluster which is characteristic of native Ha. japonica Fd.