6WMM

Human poly-N-acetyl-lactosamine synthase structure demonstrates a modular assembly of catalytic subsites for GT-A glycosyltransferases

  • Classification: TRANSFERASE
  • Organism(s): Homo sapiens
  • Expression System: Homo sapiens
  • Mutation(s): No 

  • Deposited: 2020-04-21 Released: 2020-12-02 
  • Deposition Author(s): Kadirvelraj, R., Wood, Z.A.
  • Funding Organization(s): National Institutes of Health/National Human Genome Research Institute (NIH/NHGRI)

Experimental Data Snapshot

  • Method: X-RAY DIFFRACTION
  • Resolution: 1.55 Å
  • R-Value Free: 0.198 
  • R-Value Work: 0.177 
  • R-Value Observed: 0.178 

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Ligand Structure Quality Assessment 


This is version 1.2 of the entry. See complete history


Literature

Comparison of human poly-N-acetyl-lactosamine synthase structure with GT-A fold glycosyltransferases supports a modular assembly of catalytic subsites.

Kadirvelraj, R.Yang, J.Y.Kim, H.W.Sanders, J.H.Moremen, K.W.Wood, Z.A.

(2020) J Biol Chem 296: 100110-100110

  • DOI: https://doi.org/10.1074/jbc.RA120.015305
  • Primary Citation of Related Structures:  
    6WMM

  • PubMed Abstract: 

    Poly-N-acetyl-lactosamine (poly-LacNAc) structures are composed of repeating [-Galβ(1,4)-GlcNAcβ(1,3)-] n glycan extensions. They are found on both N- and O-glycoproteins and glycolipids and play an important role in development, immune function, and human disease. The majority of mammalian poly-LacNAc is synthesized by the alternating iterative action of β1,3-N-acetylglucosaminyltransferase 2 (B3GNT2) and β1,4-galactosyltransferases. B3GNT2 is in the largest mammalian glycosyltransferase family, GT31, but little is known about the structure, substrate recognition, or catalysis by family members. Here we report the structures of human B3GNT2 in complex with UDP:Mg 2+ and in complex with both UDP:Mg 2+ and a glycan acceptor, lacto-N-neotetraose. The B3GNT2 structure conserves the GT-A fold and the DxD motif that coordinates a Mg 2+ ion for binding the UDP-GlcNAc sugar donor. The acceptor complex shows interactions with only the terminal Galβ(1,4)-GlcNAcβ(1,3)- disaccharide unit, which likely explains the specificity for both N- and O-glycan acceptors. Modeling of the UDP-GlcNAc donor supports a direct displacement inverting catalytic mechanism. Comparative structural analysis indicates that nucleotide sugar donors for GT-A fold glycosyltransferases bind in similar positions and conformations without conserving interacting residues, even for enzymes that use the same donor substrate. In contrast, the B3GNT2 acceptor binding site is consistent with prior models suggesting that the evolution of acceptor specificity involves loops inserted into the stable GT-A fold. These observations support the hypothesis that GT-A fold glycosyltransferases employ coevolving donor, acceptor, and catalytic subsite modules as templates to achieve the complex diversity of glycan linkages in biological systems.


  • Organizational Affiliation

    Department of Biochemistry & Molecular Biology, University of Georgia, Athens, Georgia, USA.


Macromolecules
Find similar proteins by:  (by identity cutoff)  |  3D Structure
Entity ID: 1
MoleculeChains Sequence LengthOrganismDetailsImage
N-acetyllactosaminide beta-1,3-N-acetylglucosaminyltransferase 2
A, B
364Homo sapiensMutation(s): 0 
Gene Names: B3GNT2B3GALT7B3GNT1
EC: 2.4.1.149
UniProt & NIH Common Fund Data Resources
Find proteins for Q9NY97 (Homo sapiens)
Explore Q9NY97 
Go to UniProtKB:  Q9NY97
PHAROS:  Q9NY97
GTEx:  ENSG00000170340 
Entity Groups  
Sequence Clusters30% Identity50% Identity70% Identity90% Identity95% Identity100% Identity
UniProt GroupQ9NY97
Sequence Annotations
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  • Reference Sequence
Oligosaccharides

Help

Entity ID: 2
MoleculeChains Length2D Diagram Glycosylation3D Interactions
beta-D-mannopyranose-(1-4)-2-acetamido-2-deoxy-beta-D-glucopyranose-(1-4)-2-acetamido-2-deoxy-beta-D-glucopyranose
C, D
3N-Glycosylation
Glycosylation Resources
GlyTouCan:  G15407YE
GlyCosmos:  G15407YE
GlyGen:  G15407YE
Small Molecules
Ligands 5 Unique
IDChains Name / Formula / InChI Key2D Diagram3D Interactions
UDP
Query on UDP

Download Ideal Coordinates CCD File 
F [auth A],
M [auth B]
URIDINE-5'-DIPHOSPHATE
C9 H14 N2 O12 P2
XCCTYIAWTASOJW-XVFCMESISA-N
EPE
Query on EPE

Download Ideal Coordinates CCD File 
J [auth A],
O [auth B]
4-(2-HYDROXYETHYL)-1-PIPERAZINE ETHANESULFONIC ACID
C8 H18 N2 O4 S
JKMHFZQWWAIEOD-UHFFFAOYSA-N
NAG
Query on NAG

Download Ideal Coordinates CCD File 
G [auth A],
N [auth B]
2-acetamido-2-deoxy-beta-D-glucopyranose
C8 H15 N O6
OVRNDRQMDRJTHS-FMDGEEDCSA-N
EDO
Query on EDO

Download Ideal Coordinates CCD File 
H [auth A],
I [auth A],
K [auth A],
P [auth B],
Q [auth B]
1,2-ETHANEDIOL
C2 H6 O2
LYCAIKOWRPUZTN-UHFFFAOYSA-N
MG
Query on MG

Download Ideal Coordinates CCD File 
E [auth A],
L [auth B]
MAGNESIUM ION
Mg
JLVVSXFLKOJNIY-UHFFFAOYSA-N
Modified Residues  1 Unique
IDChains TypeFormula2D DiagramParent
MSE
Query on MSE
A, B
L-PEPTIDE LINKINGC5 H11 N O2 SeMET
Experimental Data & Validation

Experimental Data

  • Method: X-RAY DIFFRACTION
  • Resolution: 1.55 Å
  • R-Value Free: 0.198 
  • R-Value Work: 0.177 
  • R-Value Observed: 0.178 
  • Space Group: P 21 21 21
Unit Cell:
Length ( Å )Angle ( ˚ )
a = 48.73α = 90
b = 110.92β = 90
c = 147.4γ = 90
Software Package:
Software NamePurpose
PHENIXrefinement
XSCALEdata scaling
PHASERphasing
PDB_EXTRACTdata extraction
XDSdata reduction

Structure Validation

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Ligand Structure Quality Assessment 


Entry History & Funding Information

Deposition Data


Funding OrganizationLocationGrant Number
National Institutes of Health/National Human Genome Research Institute (NIH/NHGRI)United States1P01GM107012-02

Revision History  (Full details and data files)

  • Version 1.0: 2020-12-02
    Type: Initial release
  • Version 1.1: 2020-12-09
    Changes: Database references
  • Version 1.2: 2021-04-28
    Changes: Database references