2yqh

From Proteopedia

Revision as of 12:48, 23 January 2008

Crystal structure of uridine-diphospho-N-acetylglucosamine pyrophosphorylase from Candida albicans, in the substrate-binding form

Overview

Uridine-diphospho-N-acetylglucosamine (UDP-GlcNAc) is a precursor of the, bacterial and fungal cell wall. It is also used in a component of N-linked, glycosylation and the glycosylphosphoinositol anchor of eukaryotic, proteins. It is synthesized from Nacetylglucosamine-1-phopsphate, (GlcNAc-1-P) and uridine-5'-triphosphate (UTP) by UDPGlcNAc, pyrophosphorylase (UAP). This is SN2 reaction; the non-esterified oxygen, atom of the GlcNAc-1-P phosphate group attacks the alpha-phosphate group, of UTP. We determined crystal structures of UAP from Candida albicans, (CaUAP1) without any ligands and also complexed with its substrate or with, its product. The series of structures in different forms shows the, induced-fit movements of CaUAP1. Three loops approaching the ligand, molecule close the active site when ligand is bound. In addition, Lys-421, instead of the metal ion in prokaryotic UAPs, is coordinated by both, phosphate groups of UDPGlcNAc and acts as a co-factor. However, a, magnesium ion enhances the enzymatic activity of CaUAP1, and, thus, we, propose that the magnesium ion increases the affinity between UTP and the, enzyme by coordinating to the alpha- and gamma-phosphate group of UTP.

About this Structure

2YQH is a Single protein structure of sequence from Candida albicans with , , and as ligands. Active as UDP-N-acetylglucosamine diphosphorylase, with EC number 2.7.7.23 Full crystallographic information is available from OCA.

Reference

Crystal structure of uridine-diphospho-N-acetylglucosamine pyrophosphorylase from Candida albicans and catalytic reaction mechanism., Maruyama D, Nishitani Y, Nonaka T, Kita A, Fukami TA, Mio T, Yamada-Okabe H, Yamada-Okabe T, Miki K, J Biol Chem. 2007 Mar 28;. PMID:17392279

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