Identification of the archaeal NMN adenylyltransferase gene

Increasing evidence on the importance of fluctuations in NAD(+) levels in t he living cell is accumulating. Therefore a deeper knowledge on the regulat ion of coenzyme synthesis and recycling is required. In this context the st udy of NMN adenylyltransferase (EC 2.7.7.1), a key enzyme in the NAD(+) bio synthetic pathway, assumes a remarkable relevance. We have previously purif ied to homogeneity and characterized the protein from the thermophilic arch aeon Sulfolobus solfataricus. The determination of partial sequence of the S. solfataricus enzyme, together with the recent availability of the genome sequence of the archaeon Methanococcus jannaschii, allowed us, based on se quence similarity, to identify the hi. jannaschii NMN adenylyltransferase g ene. As far as we know from literature, this is the first report on the NMN adenylyltransferase gene.