CLONING AND SEQUENCING OF 4 STRUCTURAL GENES FOR THE NA-TRANSLOCATINGNADH-UBIQUINONE OXIDOREDUCTASE OF VIBRIO-ALGINOLYTICUS()

Oligonucleotide probes based on the N-terminal amino acid sequences of the NqrA and NqrC subunits were used to clone genes for the Na+-depen dent NADH-ubiquinone oxidoreductase complex from Vibrio alginolyticus. Four consecutive ORFs were identified encoding subunit proteins of 48 .6, 46.8, 27.7 and 22.6 kDa, respectively (NqrA-D). A further ORF, sho wing 71% homology to the BolA protein of Escherichia coli, was located upstream. From sequence comparisons, we conclude that the Na+-depende nt NADH-ubiquinone oxidoreductase complex of V. alginolyticus is clear ly distinct from the corresponding H+-dependent enzymes of both prokar yotes and eukaryotes.