We have cloned a cya gene from a human pathogen Mycobacterium tuberculosis H37Rv by complementation of catabolic defect. (Accession No. AF017731, 1977). M. tuberculosis H37Rv genome sequence revealed five genes (Rv1264, Rv1318c, Rv1319c, Rv1320c, and Rv1625c) for putative adenylyl cyclases (Cole et. al., Nature, 393, 537-544, 1998). Screening the genomic library for complementation of catabolic defect produced eight clones of the same gene (Mtb cya) annotated later as Rv1625c but none of the other genes. Genes Rv1318c, Rv1319c, and Rv1320c have about 70% identity among themselves whereas Rv1264 and Rv1625c have about 20% identity within this group of genes. Mtb cya (Rv1625c) was expressed in Escherichia coli with adenylyl cyclase activity of xxx nmoles cAMP/min.mg protein. Genes Rv1264 and Rv1320c were cloned by PCR and expressed in E. coli. We did not detect adenylyl cyclase activity for these two gene products using Mg-ATP as the substrate. However, with Mn-ATP as the substrate, Rv1264 gene product had adenylyl cyclase activity, albeit very low, ( ) but Rv1320c gene product was still inactive for cAMP production.
Citation: Journal of Biological Chemistry
Issue: No. 37
Pub Type: Journals
Adenylyl Cyclase, Cyclic AMP, Mycobacteria