Characterisation of glutamine fructose-6-phosphate amidotransferase (EC 2.6.1.16) and N-acetylglucosamine metabolism in Bifidobacterium

A�ssi, Eliane; Foley, Sophie; Stolarczyk, Emilie; Mouni, Fadoua; Brassart, Colette; Vidal, Olivier; Aissi, Eliane; Bouquelet, St�phane; Krzewinski, Fr�d�ric

Abstract

Bifidobacterium bifidum, in contrast to other bifido-bacterial species, is auxotrophic for N-acetylglucosamine. Growth experiments revealed assimilation of radiolabelled N-acetylglucosamine in bacterial cell walls and in acetate, an end-product of central metabolism via the bifidobacterial d-fructose-6-phosphate shunt. While supplementation with fructose led to reduced N-acetyl-glucosamine assimilation via the d-fructose-6-phosphate shunt, no significant difference was observed in levels of radiolabelled N-acetylglucosamine incorporated into cell walls. Considering the central role played by glutamine fructose-6-phosphate transaminase (GlmS) in linking the biosynthetic pathway for N-acetylglucosamine to hexose metabolism, the GlmS of Bifidobacterium was characterized. The genes encoding the putative GlmS of B. longum DSM20219 and B. bifidum DSM20082 were cloned and sequenced. Bioinformatic analyses of the predicted proteins revealed 43% amino acid identity with the Escherichia coli GlmS, with conservation of key amino acids in the catalytic domain. The B. longum GlmS was over-produced as a histidine-tagged fusion protein. The purified C-terminal His-tagged GlmS possessed glutamine fructose-6-phosphate amidotransferase activity as demonstrated by synthesis of glucosamine-6-phosphate from fructose-6-phosphate and glutamine. It also possesses an independent glutaminase activity, converting glutamine to glutamate in the absence of fructose-6-phosphate. This is of interest considering the apparently reduced coding potential in bifidobacteria for enzymes associated with glutamine metabolism.

Citation

Aïssi, E., Foley, S., Stolarczyk, E., Mouni, F., Brassart, C., Vidal, O., …Krzewinski, F. (2008). Characterisation of glutamine fructose-6-phosphate amidotransferase (EC 2.6.1.16) and N-acetylglucosamine metabolism in Bifidobacterium. Archives of Microbiology, 189(2), 157-167. https://doi.org/10.1007/s00203-007-0307-9

• Journal Article Type: Article
• Acceptance Date: Sep 13, 2007
• Online Publication Date: Oct 18, 2007
• Publication Date: 2008-02
• Deposit Date: Jul 21, 2008
• Journal: Archives of Microbiology
• Print ISSN: 0302-8933
• Electronic ISSN: 1432-072X
• Publisher: BMC
• Peer Reviewed: Peer Reviewed
• Volume: 189
• Issue: 2
• Pages: 157-167
• DOI: https://doi.org/10.1007/s00203-007-0307-9
• Keywords: Bifidobacterium; GlmS; Glutamine fructose-6-phosphate amidotransferase; N-acetylglucosamine; Glutaminase activity
• Public URL: http://researchrepository.napier.ac.uk/id/eprint/1739
• Publisher URL: http://dx.doi.org/10.1007/s00203-007-0307-9