SEQUENCE AND TRANSCRIPTIONAL ANALYSIS OF THE NOURSEOTHRICIN ACETYLTRANSFERASE-ENCODING GENE NAT1 FROM STREPTOMYCES-NOURSEI

We have determined the nucleotide (nt) sequence of nat1, a gene encodi ng nourseothricin (Nc) acetyltransferase (AT) from Streptomyces nourse i, and its transcriptional start point (tsp). The nt sequence upstream from the coding region is completely different from that of the stat gene (encoding streptothricin AT) from Streptomyces lavendulae [S. Hor inouchi, K. Furuya, M. Nishiyama, H. Suzuki and T. Beppu, J. Bacteriol . 169 (1987) 1929-1937], even though the nt sequences of the two genes and the deduced amino acid (aa) sequences of the two enzymes show a h igh degree of similarity. Another stat gene, derived from a Gram-negat ive plasmid, showed only deduced aa similarity, but not nt sequence si milarity, to the above two. A database search for related aa sequences did not reveal any clear-cut homologies to other types of protein. A multiple aa sequence alignment of several ATs is presented.