1YRO

Crystal structure of beta14,-galactosyltransferase mutant ARG228Lys in complex with alpha-lactalbumin in the presence of UDP-galactose and Mn


Experimental Data Snapshot

  • Method: X-RAY DIFFRACTION
  • Resolution: 1.90 Å
  • R-Value Free: 0.225 
  • R-Value Work: 0.189 
  • R-Value Observed: 0.189 

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Ligand Structure Quality Assessment 


This is version 1.3 of the entry. See complete history


Literature

Mutation of Arginine 228 to Lysine Enhances the Glucosyltransferase Activity of Bovine beta-1,4-Galactosyltransferase I

Ramakrishnan, B.Boeggeman, E.Qasba, P.K.

(2005) Biochemistry 44: 3202-3210

  • DOI: 10.1021/bi0479454
  • Primary Citation of Related Structures:  
    1YRO

  • PubMed Abstract: 
  • Beta-1,4-galactosyltransferase I (beta4Gal-T1) normally transfers Gal from UDP-Gal to GlcNAc in the presence of Mn(2+) ion (Gal-T activity) and also transfers Glc from UDP-Glc to GlcNAc (Glc-T activity), albeit at only 0.3% efficiency. In addition, alpha-lactalbumin (LA) enhances this Glc-T activity more than 25 times ...

    Beta-1,4-galactosyltransferase I (beta4Gal-T1) normally transfers Gal from UDP-Gal to GlcNAc in the presence of Mn(2+) ion (Gal-T activity) and also transfers Glc from UDP-Glc to GlcNAc (Glc-T activity), albeit at only 0.3% efficiency. In addition, alpha-lactalbumin (LA) enhances this Glc-T activity more than 25 times. Comparison of the crystal structures of UDP-Gal- and UDP-Glc-bound beta4Gal-T1 reveals that the O4 hydroxyl group in both Gal and Glc moieties forms a hydrogen bond with the side chain carboxylate group of Glu317. The orientation of the O4 hydroxyl of glucose causes a steric hindrance to the side chain carboxylate group of Glu317, accounting for the enzyme's low Glc-T activity. In this study, we show that mutation of Arg228, a residue in the vicinity of Glu317, to lysine (R228K-Gal-T1) results in a 15-fold higher Glc-T activity, which is further enhanced by LA to nearly 25% of the Gal-T activity of the wild type. The kinetic parameters indicate that the main effect of the mutation of Arg228 to lysine is on the k(cat) of Glc-T, which increases 3-4-fold, both in the absence and in the presence of LA; simultaneously, the k(cat) for the Gal-T reaction is reduced 30-fold. The crystal structure of R228K-Gal-T1 complexed with LA, UDP-Gal, and Mn(2+) determined at 1.9 A resolution shows that the Asp318 side chain exhibits a minor alternate conformation, compared to that in the wild type. This alternate conformation now causes a steric hindrance to the O4 hydroxyl group of the Gal moiety of UDP-Gal, probably causing the dissociation of UDP-Gal and the reduced k(cat) of the Gal-T reaction.


    Organizational Affiliation

    Structural Glycobiology Section, Laboratory of Experimental and Computational Biology, Center for Cancer Research, National Cancer Institute-Frederick, Frederick, Maryland 21702-1201, USA.



Macromolecules
Find similar proteins by:  (by identity cutoff)  |  Structure
Entity ID: 1
MoleculeChainsSequence LengthOrganismDetailsImage
ALPHA-LACTALBUMINA, C123Mus musculusMutation(s): 0 
Gene Names: alpha-lactalbuminLalba
UniProt
Find proteins for P29752 (Mus musculus)
Explore P29752 
Go to UniProtKB:  P29752
Protein Feature View
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  • Reference Sequence
Find similar proteins by:  (by identity cutoff)  |  Structure
Entity ID: 2
MoleculeChainsSequence LengthOrganismDetailsImage
BETA-1,4-GALACTOSYLTRANSFERASEB, D286Bos taurusMutation(s): 2 
Gene Names: beta14-galactosyltransferaseB4GALT1GALTGGTB2
EC: 2.4.1.22 (PDB Primary Data), 2.4.1.90 (PDB Primary Data), 2.4.1.38 (PDB Primary Data), 2.4.1 (UniProt), 2.4.1.275 (UniProt)
UniProt
Find proteins for P08037 (Bos taurus)
Explore P08037 
Go to UniProtKB:  P08037
Protein Feature View
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  • Reference Sequence
Small Molecules
Ligands 6 Unique
IDChainsName / Formula / InChI Key2D Diagram3D Interactions
GDU (Subject of Investigation/LOI)
Query on GDU

Download Ideal Coordinates CCD File 
H [auth B], M [auth D]GALACTOSE-URIDINE-5'-DIPHOSPHATE
C15 H24 N2 O17 P2
HSCJRCZFDFQWRP-ABVWGUQPSA-N
 Ligand Interaction
UDP (Subject of Investigation/LOI)
Query on UDP

Download Ideal Coordinates CCD File 
J [auth B], O [auth D]URIDINE-5'-DIPHOSPHATE
C9 H14 N2 O12 P2
XCCTYIAWTASOJW-XVFCMESISA-N
 Ligand Interaction
MES
Query on MES

Download Ideal Coordinates CCD File 
F [auth A]2-(N-MORPHOLINO)-ETHANESULFONIC ACID
C6 H13 N O4 S
SXGZJKUKBWWHRA-UHFFFAOYSA-N
 Ligand Interaction
PG4
Query on PG4

Download Ideal Coordinates CCD File 
G [auth A], L [auth C]TETRAETHYLENE GLYCOL
C8 H18 O5
UWHCKJMYHZGTIT-UHFFFAOYSA-N
 Ligand Interaction
MN
Query on MN

Download Ideal Coordinates CCD File 
I [auth B], N [auth D]MANGANESE (II) ION
Mn
WAEMQWOKJMHJLA-UHFFFAOYSA-N
 Ligand Interaction
CA
Query on CA

Download Ideal Coordinates CCD File 
E [auth A], K [auth C]CALCIUM ION
Ca
BHPQYMZQTOCNFJ-UHFFFAOYSA-N
 Ligand Interaction
Experimental Data & Validation

Experimental Data

  • Method: X-RAY DIFFRACTION
  • Resolution: 1.90 Å
  • R-Value Free: 0.225 
  • R-Value Work: 0.189 
  • R-Value Observed: 0.189 
  • Space Group: P 1 21 1
Unit Cell:
Length ( Å )Angle ( ˚ )
a = 57.334α = 90
b = 94.087β = 101.64
c = 99.705γ = 90
Software Package:
Software NamePurpose
HKL-2000data collection
SCALEPACKdata scaling
AMoREphasing
CNSrefinement
HKL-2000data reduction

Structure Validation

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Ligand Structure Quality Assessment  



Entry History 

Deposition Data

Revision History  (Full details and data files)

  • Version 1.0: 2005-03-22
    Type: Initial release
  • Version 1.1: 2007-10-16
    Changes: Version format compliance
  • Version 1.2: 2011-07-13
    Changes: Version format compliance
  • Version 1.3: 2017-10-11
    Changes: Data collection