1V83

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

Summary for 1V83

• Entry DOI: 10.2210/pdb1v83/pdb
• Related: 1V82 1V84
• Descriptor: Galactosylgalactosylxylosylprotein 3-beta-glucuronosyltransferase 1, MANGANESE (II) ION, L(+)-TARTARIC ACID, ... (5 entities in total)
• Functional Keywords: transferase, glycoprotein, glycocyltransferase, hnk-1 epitope
• Biological source: Homo sapiens (human)
• Cellular location: Golgi apparatus membrane; Single-pass type II membrane protein: Q9P2W7
• Total number of polymer chains: 2
• Total formula weight: 59145.10

Authors

Kakuda, S.,Shiba, T.,Ishiguro, M.,Tagawa, H.,Oka, S.,Kajihara, Y.,Kawasaki, T.,Wakatsuki, S.,Kato, R. (deposition date: 2003-12-27, release date: 2004-05-25, Last modification date: 2023-10-25)

Primary citation

Kakuda, S.,Shiba, T.,Ishiguro, M.,Tagawa, H.,Oka, S.,Kajihara, Y.,Kawasaki, T.,Wakatsuki, S.,Kato, R.
Structural Basis for Acceptor Substrate Recognition of a Human Glucuronyltransferase, GlcAT-P, an Enzyme Critical in the Biosynthesis of the Carbohydrate Epitope HNK-1
J.Biol.Chem., 279:22693-22703, 2004

PubMed Abstract: 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.

PubMed: 14993226
DOI: 10.1074/jbc.M400622200

Experimental method

X-RAY DIFFRACTION (1.9 Å)