MOLECULAR-CLONING AND DETERMINATION OF THE NUCLEOTIDE-SEQUENCE OF A GENE ENCODING SALT-TOLERANT GLUTAMINASE FROM MICROCOCCUS-LUTEUS K-3

The gene encoding the salt-tolerant glutaminase I from marine Micrococ cus luteus K-3 (M. luteus K-3) was cloned in Escherichia coli (E. coli ) JM109. Clones were screened by hybridization with degenerate oligonu cleotide probes designed using the known N-terminal amino acid sequenc e of glutaminase I from M. luteus K-3. A 2.4-kb HincII fragment from a 8-kb primary cloned DNA fragment was subcloned and sequenced. This fr agment had an open reading frame of 1,368 nucleotides encoding 456 ami no acids. The molecular weight of the deduced amino acid sequence of g lutaminase I was determined to be 48,247. Comparison of the amino acid sequence of glutaminase I with those of kidney, brain, liver, and Cae norhabditis elegans glutaminases revealed high degrees of homology in several local regions.