Respiratory nitrate reductase of Escherichia coli. Sequence identification of the large subunit gene.

The nucleotide sequence is presented of part of the transcription initiation end of the nar operon of Escherichia coli K12, which encodes the respiratory nitrate reductase complex. The first coding sequence transcribed is the narG gene, encoding the large catalytic molybdoprotein of the complex. This sequence was assigned unambiguously by automated N-terminal amino acid sequencing of the purified large subunit. The deduced partial amino acid sequence of this polypeptide is hydrophilic and rich in basic residues. Membrane insertion does not involve N-terminal proteolytic processing of this subunit.