RT Journal Article SR Electronic(1) A1 Sanangelantoni, Anna M. A1 Forlani, Giuseppe A1 Ambroselli, Franco A1 Cammarano, Piero A1 Tiboni, OrsolaYR 1992 T1 The glnA gene of the extremely thermophilic eubacterium Thermotoga maritima: cloning, primary structure, and expression in Escherichia coli JF Microbiology, VO 138 IS 2 SP 383 OP 393 DO https://doi.org/10.1099/00221287-138-2-383 PB Microbiology Society, SN 1465-2080, AB SUMMARY: The structural gene (glnA) encoding the glutamine synthetase (GS) of the extremely thermophilic eubacterium Thermotoga maritima has been cloned on a 6ยท0 kb HindIII DNA fragment. Sequencing of the region containing the glnA gene (1444 bp) showed an ORF encoding a polypeptide (439 residues) with an estimated mass of 50088 Da, which shared significant homology with the GSI sequences of other Bacteria (Escherichia coli, Bacillus subtilis) and Archaea (Pyrococcus woesei, Sulfolobus solfataricus). The T. maritima glnA gene was expressed in E. coli, as shown by the ability to complement a glnA lesion in the glutamine-auxotrophic strain ET8051. The recombinant GS has been partially characterized with respect to the temperature dependence of enzyme activity, molecular mass and mode of regulation. The molecular mass of the Thermotoga GS (590000 Da), estimated by gel filtration, was compatible with a dodecameric composition for the holoenzyme, as expected for a glutamine synthetase of the GSI type. Comparison of the amino acid sequence of T. maritima GS with those from thermophilic and mesophilic micro-organisms failed to detect any obvious features directly related to thermal stability., UL https://www.microbiologyresearch.org/content/journal/micro/10.1099/00221287-138-2-383