2VS3

THE BINDING OF UDP-GALACTOSE BY AN ACTIVE SITE MUTANT OF alpha-1,3 GALACTOSYLTRANSFERASE (alpha3GT)

Summary for 2VS3

• Entry DOI: 10.2210/pdb2vs3/pdb
• Related: 1FG5 1G8O 1G93 1GWV 1GWW 1GX0 1GX4 1K4V 1O7O 1O7Q 1VZT 1VZU 1VZX 2JCF 2JCJ 2JCK 2JCL 2JCO 2VFZ 2VS4
• Related PRD ID: PRD_900019
• Descriptor: N-ACETYLLACTOSAMINIDE ALPHA-1,3-GALACTOSYLTRANSFERASE, beta-D-galactopyranose-(1-4)-2-acetamido-2-deoxy-alpha-D-glucopyranose, URIDINE-5'-DIPHOSPHATE, ... (5 entities in total)
• Functional Keywords: manganese, transferase, glycoprotein, metal-binding, active-site mutant, glycosyltransferase, n-acetyl lactosamine, signal-anchor, transmembrane, golgi apparatus, gt, udp, membrane, alpha3gt, galactose, alpha-3gt
• Biological source: BOS TAURUS (BOVINE)
• Cellular location: Golgi apparatus, Golgi stack membrane; Single-pass type II membrane protein: P14769
• Total number of polymer chains: 2
• Total formula weight: 69863.26

Authors

Tumbale, P.,Jamaluddin, H.,Thiyagarajan, N.,Brew, K.,Acharya, K.R. (deposition date: 2008-04-18, release date: 2008-07-15, Last modification date: 2023-12-13)

Primary citation

Tumbale, P.,Jamaluddin, H.,Thiyagarajan, N.,Brew, K.,Acharya, K.R.
Structural Basis of Udp-Galactose Binding by Alpha- 1,3-Galactosyltransferase (Alpha3Gt): Role of Negative Charge on Aspartic Acid 316 in Structure and Activity.
Biochemistry, 47:8711-, 2008

PubMed Abstract: alpha-1,3-Galactosyltransferase (alpha3GT) catalyzes the transfer of galactose from UDP-galactose to form an alpha 1-3 link with beta-linked galactosides; it is part of a family of homologous retaining glycosyltransferases that includes the histo-blood group A and B glycosyltransferases, Forssman glycolipid synthase, iGb3 synthase, and some uncharacterized prokaryotic glycosyltransferases. In mammals, the presence or absence of active forms of these enzymes results in antigenic differences between individuals and species that modulate the interplay between the immune system and pathogens. The catalytic mechanism of alpha3GT is controversial, but the structure of an enzyme complex with the donor substrate could illuminate both this and the basis of donor substrate specificity. We report here the structure of the complex of a low-activity mutant alpha3GT with UDP-galactose (UDP-gal) exhibiting a bent configuration stabilized by interactions of the galactose with multiple residues in the enzyme including those in a highly conserved region (His315 to Ser318). Analysis of the properties of mutants containing substitutions for these residues shows that catalytic activity is strongly affected by His315 and Asp316. The negative charge of Asp316 is crucial for catalytic activity, and structural studies of two mutants show that its interaction with Arg202 is needed for an active site structure that facilitates the binding of UDP-gal in a catalytically competent conformation.

PubMed: 18651752
DOI: 10.1021/BI800852A

Experimental method

X-RAY DIFFRACTION (2.2 Å)