The azurin gene from Pseudomonas aeruginosa

Abstract
We have cloned and sequenced the Pseudomonas aeruginosa azurin structural gene and its flanking regions. The DNA sequence predicts a pre-protein with a signal peptide of 19 amino acids followed by the 128-amino-acid mature azurin protein. Nuclease S1 mapping and primer elongation experiments indicated two 5''-termini of the azurin transcript. The major transcript of the azurin gene is initiated around 35 base pairs upstream from the translational start. The minor transcript, with a promoter region sharing homology with a consensus nif promoter of Klebsiella pneumoniae and also with other Pseudomonas genes, is initiated 145 base pairs upstreams of the azurin initiation codon. Downstream from the azurin structural gene a sequence similar to a transcriptional terminator is found. Northern blot analysis indicated two sizes of the azurin mRNA (0.54 kb and 0.65 kb) confirming the S1 mapping and the predictions from the nucleotide sequence.