CLONING AND SEQUENCING OF THE GENE CODING FOR THE LARGE SUBUNIT OF METHYLAMINE DEHYDROGENASE FROM THIOBACILLUS-VERSUTUS

The gene that codes for the alpha-subunit of methylamine dehydrogenase from Thiobacillus versutus, madA, was cloned and sequenced. It codes for a protein of 395 amino acids preceded by a leader sequence of 31 amino acids. The derived amino acid sequence was confirmed by partial amino acid sequencing. The start of the mature protein could not be determined by direct sequencing, since the N terminus appeared to be blocked. Instead, it was determined by electrospray mass spectrometry. Confirmation of the results was obtained by sequencing the N terminus after pyroglutamate aminopeptidase, digestion. The sequence is homologous to the Paracoccus denitrificans nucleotide sequence. A second open reading frame, called open reading frame 3, is located immediately downstream of madA.