Sequence and molecular analysis of the Rhizobium etli glsA gene, encoding a thermolabile glutaminase

We sequenced a 2.1 kb fragment of DNA carrying the structural glsA gene, wh ich codes for the Rhizobium etli thermolabile glutaminase (A). The glsA gen e complements the R. etli LM16 mutant that lacks glutaminase A activity, an d is expressed in the heterologous host Sinorhizobium meliloti. The deduced amino acid sequence consists of 309 residues, with a calculated molecular mass of 33 kDa. The amino acid sequence shares 53% and 43% identity with tw o hypothetical glutaminases of E. coli; 42% identity with liver-type; 38% i dentity with kidney-type glutaminase; 41% and 40% identity hypothetical glu taminases of Bacillus subtilis; and 41% and 37% identity with two putative glutaminases of Caenorhabditis elegans. The glsA gene represents the first glutaminase gene cloned and sequenced in prokaryotes. (C) 1999 Published by Elsevier Science B.V. All rights reserved.