4U8K

Structure of Aspergillus fumigatus UDP-Galactopyranose mutase mutant Q107A


Experimental Data Snapshot

  • Method: X-RAY DIFFRACTION
  • Resolution: 2.2 Å
  • R-Value Free: 0.207 
  • R-Value Work: 0.174 

wwPDB Validation 3D Report Full Report


This is version 1.2 of the entry. See complete history

Literature

Contributions of Unique Active Site Residues of Eukaryotic UDP-Galactopyranose Mutases to Substrate Recognition and Active Site Dynamics.

Da Fonseca, I.Qureshi, I.A.Mehra-Chaudhary, R.Kizjakina, K.Tanner, J.J.Sobrado, P.

(2014) Biochemistry 53: 7794-7804

  • DOI: 10.1021/bi501008z
  • Primary Citation of Related Structures:  

  • PubMed Abstract: 
  • UDP-galactopyranose mutase (UGM) catalyzes the interconversion between UDP-galactopyranose and UDP-galactofuranose. Absent in humans, galactofuranose is found in bacterial and fungal cell walls and is a cell surface virulence factor in protozoan para ...

    UDP-galactopyranose mutase (UGM) catalyzes the interconversion between UDP-galactopyranose and UDP-galactofuranose. Absent in humans, galactofuranose is found in bacterial and fungal cell walls and is a cell surface virulence factor in protozoan parasites. For these reasons, UGMs are targets for drug discovery. Here, we report a mutagenesis and structural study of the UGMs from Aspergillus fumigatus and Trypanosoma cruzi focused on active site residues that are conserved in eukaryotic UGMs but are absent or different in bacterial UGMs. Kinetic analysis of the variants F66A, Y104A, Q107A, N207A, and Y317A (A. fumigatus numbering) show decreases in k(cat)/K(M) values of 200-1000-fold for the mutase reaction. In contrast, none of the mutations significantly affect the kinetics of enzyme activation by NADPH. These results indicate that the targeted residues are important for promoting the transition state conformation for UDP-galactofuranose formation. Crystal structures of the A. fumigatus mutant enzymes were determined in the presence and absence of UDP to understand the structural consequences of the mutations. The structures suggest important roles for Asn207 in stabilizing the closed active site, and Tyr317 in positioning of the uridine ring. Phe66 and the corresponding residue in Mycobacterium tuberculosis UGM (His68) play a role as the backstop, stabilizing the galactopyranose group for nucleophilic attack. Together, these results provide insight into the essentiality of the targeted residues for realizing maximal catalytic activity and a proposal for how conformational changes that close the active site are temporally related and coupled together.


    Organizational Affiliation

    Department of Biochemistry, Virginia Tech , Blacksburg, Virginia 24061, United States.




Macromolecules

Find similar proteins by: Sequence  |  Structure

Entity ID: 1
MoleculeChainsSequence LengthOrganismDetails
UDP-galactopyranose mutase
A, B, C, D
513Neosartorya fumigataMutation(s): 4 
Gene Names: glf (glfA)
EC: 5.4.99.9
Find proteins for Q4W1X2 (Neosartorya fumigata)
Go to UniProtKB:  Q4W1X2
Small Molecules
Ligands 3 Unique
IDChainsName / Formula / InChI Key2D Diagram3D Interactions
SO4
Query on SO4

Download SDF File 
Download CCD File 
A, B, C, D
SULFATE ION
O4 S
QAOWNCQODCNURD-UHFFFAOYSA-L
 Ligand Interaction
EDO
Query on EDO

Download SDF File 
Download CCD File 
A, B, C, D
1,2-ETHANEDIOL
ETHYLENE GLYCOL
C2 H6 O2
LYCAIKOWRPUZTN-UHFFFAOYSA-N
 Ligand Interaction
FDA
Query on FDA

Download SDF File 
Download CCD File 
A, B, C, D
DIHYDROFLAVINE-ADENINE DINUCLEOTIDE
C27 H35 N9 O15 P2
YPZRHBJKEMOYQH-UYBVJOGSSA-N
 Ligand Interaction
Experimental Data & Validation

Experimental Data

  • Method: X-RAY DIFFRACTION
  • Resolution: 2.2 Å
  • R-Value Free: 0.207 
  • R-Value Work: 0.174 
  • Space Group: P 65 2 2
Unit Cell:
Length (Å)Angle (°)
a = 216.190α = 90.00
b = 216.190β = 90.00
c = 318.767γ = 120.00
Software Package:
Software NamePurpose
PDB_EXTRACTdata extraction
PHENIXrefinement
PHENIXrefinement
XDSdata reduction

Structure Validation

View Full Validation Report or Ramachandran Plots



Entry History & Funding Information

Deposition Data


Funding OrganizationLocationGrant Number
National Institutes of Health/National Institute of General Medical SciencesUnited StatesR01GM094469

Revision History 

  • Version 1.0: 2014-12-03
    Type: Initial release
  • Version 1.1: 2014-12-24
    Type: Database references
  • Version 1.2: 2017-09-27
    Type: Author supporting evidence, Database references, Derived calculations, Other, Source and taxonomy