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spinqualitylabelsall models 1v84, resolution 1.82Å Show:Asymmetric Unit Biological Assembly Drag the structure with the mouse to rotate   Export Animated Image

Crystal structure of human GlcAT-P in complex with N-acetyllactosamine, Udp, and Mn2+

Overview

The HNK-1 carbohydrate epitope is found on many neural cell adhesion, molecules. Its structure is characterized by a terminal sulfated, glucuronyl acid. The glucuronyltransferases, GlcAT-P and GlcAT-S, are, involved in the biosynthesis of the HNK-1 epitope, GlcAT-P as the major, enzyme. We overexpressed and purified the recombinant human GlcAT-P from, Escherichia coli. Analysis of its enzymatic activity showed that it, catalyzed the transfer reaction for N-acetyllactosamine (Galbeta1-4GlcNAc), but not lacto-N-biose (Galbeta1-3GlcNAc) as an acceptor substrate., Subsequently, we determined the first x-ray crystal structures of human, GlcAT-P, in the absence and presence of a donor substrate product UDP, catalytic Mn(2+), and an acceptor substrate analogue N-acetyllactosamine, (Galbeta1-4GlcNAc) or an asparagine-linked biantennary nonasaccharide. The, asymmetric unit contains two independent molecules. Each molecule is an, alpha/beta protein with two regions that constitute the donor and acceptor, substrate binding sites. The UDP moiety of donor nucleotide sugar is, recognized by conserved amino acid residues including a DXD motif, (Asp(195)-Asp(196)-Asp(197)). Other conserved amino acid residues interact, with the terminal galactose moiety of the acceptor substrate. In addition, Val(320) and Asn(321), which are located on the C-terminal long loop from, a neighboring molecule, and Phe(245) contribute to the interaction with, GlcNAc moiety. These three residues play a key role in establishing the, acceptor substrate specificity.

About this Structure

1V84 is a Single protein structure of sequence from Homo sapiens with MN, TLA and UDP as ligands. Active as Galactosylgalactosylxylosylprotein 3-beta-glucuronosyltransferase, with EC number 2.4.1.135 Full crystallographic information is available from OCA.

Reference

Structural basis for acceptor substrate recognition of a human glucuronyltransferase, GlcAT-P, an enzyme critical in the biosynthesis of the carbohydrate epitope HNK-1., Kakuda S, Shiba T, Ishiguro M, Tagawa H, Oka S, Kajihara Y, Kawasaki T, Wakatsuki S, Kato R, J Biol Chem. 2004 May 21;279(21):22693-703. Epub 2004 Mar 1. PMID:14993226

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