Glutamine synthetase from Lactobacillus hilgardii LMG 7934

Abstract

While lactic acid bacteria are widespread in various ecological niches with the ex cess of nutrients and extensive use in food industry, many aspects of the nitrogen metabolism of
remain unexplored. The most preferred nitrogen sources for most bacteria are glutamine and ammonium ions. In bacterial cells an enzyme glutamine synthetase synthetizes glutamine from glutamate and ammonium ion. While L. hilgardii LMG 7934 genome carries two genes encoding glutamine synthetases with 55% of mutual identity of amino acid sequences, which protein plays the major role is still unclear. One gene is located within classical glnRA operon with the gene of GlnR-like transcriptional regulator, while the second is monocistronic. In this study we report the cloning of both genes encoding glutamine synthetases from L. hilgardii LMG 7934.