2j6h

From Proteopedia

E. COLI GLUCOSAMINE-6-P SYNTHASE IN COMPLEX WITH GLUCOSE-6P AND 5-OXO-L-NORLEUCINE

Overview

Glucosamine-6P synthase catalyzes the synthesis of glucosamine-6P from fructose-6P and glutamine and uses a channel to transfer ammonia from its glutaminase to its synthase active site. X-ray structures of glucosamine-6P synthase have been determined at 2.05 Angstroms resolution in the presence of fructose-6P and at 2.35 Angstroms resolution in the presence of fructose-6P and 6-diazo-5-oxo-L-norleucine, a glutamine affinity analog that covalently modifies the N-terminal catalytic cysteine, therefore mimicking the gamma-glutamyl-thioester intermediate formed during hydrolysis of glutamine. The fixation of the glutamine analog activates the enzyme through several major structural changes: 1) the closure of a loop to shield the glutaminase site accompanied by significant domain hinging, 2) the activation of catalytic residues involved in glutamine hydrolysis, i.e. the alpha-amino group of Cys-1 and Asn-98 that is positioned to form the oxyanion hole, and 3) a 75 degrees rotation of the Trp-74 indole group that opens the ammonia channel.

About this Structure

2J6H is a Single protein structure of sequence from Escherichia coli. This structure supersedes the now removed PDB entry 2BPJ. Full crystallographic information is available from OCA.

Reference

Glutamine binding opens the ammonia channel and activates glucosamine-6P synthase., Mouilleron S, Badet-Denisot MA, Golinelli-Pimpaneau B, J Biol Chem. 2006 Feb 17;281(7):4404-12. Epub 2005 Dec 9. PMID:16339762

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