Purification of the dissimilative nitrate reductase of Pseudomonas fluorescens and the cloning and sequencing of its corresponding genes.

The dissimilative membrane-bound nitrate reductase from Pseudomonas fluorescens strain AK15 was purified and the alpha subunit of the enzyme partially sequenced. On the basis of this partial amino acid sequence and of conserved stretches of amino acids between Escherichia coli and Bacillus subtilis, degenerate primers were design to amplify the narG gene and part of the narH gene in a PCR approach. The deduced amino acid sequence of narG shows 72% and 52% and narH 78% and 62% identity to the homologous subunit of E. coli and B. subtilis, respectively.