4ag9

Publication Abstract from PubMed

Glucosamine-6-phosphate N-acetyltransferase 1 (GNA1) produces GlcNAc-6-phosphate from GlcN-6-phosphate and acetyl coenzyme A. Early mercury-labelling experiments implicated a conserved cysteine in the reaction mechanism, whereas recent structural data appear to support a mechanism in which this cysteine plays no role. Here, two crystal structures of Caenorhabditis elegans GNA1 are reported, revealing an unusual covalent complex between this cysteine and the coenzyme A product. Mass-spectrometric and reduction studies showed that this inactive covalent complex can be reactivated through reduction, yet mutagenesis of the cysteine supports a previously reported bi-bi mechanism. The data unify the apparently contradictory earlier reports on the role of a cysteine in the GNA1 active site.

Structural and biochemical characterization of a trapped coenzyme A adduct of Caenorhabditis elegans glucosamine-6-phosphate N-acetyltransferase 1.,Dorfmueller HC, Fang W, Rao FV, Blair DE, Attrill H, van Aalten DM Acta Crystallogr D Biol Crystallogr. 2012 Aug;68(Pt 8):1019-29. Epub 2012 Jul 17. PMID:22868768^[1]

From MEDLINE®/PubMed®, a database of the U.S. National Library of Medicine.