3UNC

Crystal Structure of Bovine Milk Xanthine Dehydrogenase to 1.65A Resolution


Experimental Data Snapshot

  • Method: X-RAY DIFFRACTION
  • Resolution: 1.65 Å
  • R-Value Free: 0.196 
  • R-Value Work: 0.177 

wwPDB Validation 3D Report Full Report



Literature

Protein conformational gating of enzymatic activity in xanthine oxidoreductase.

Ishikita, H.Eger, B.T.Okamoto, K.Nishino, T.Pai, E.F.

(2012) J Am Chem Soc 134: 999-1009

  • DOI: 10.1021/ja207173p
  • Primary Citation of Related Structures:  
    3AX7, 3AX9, 3UNI, 3UNA, 3UNC

  • PubMed Abstract: 
  • In mammals, xanthine oxidoreductase can exist as xanthine dehydrogenase (XDH) and xanthine oxidase (XO). The two enzymes possess common redox active cofactors, which form an electron transfer (ET) pathway terminated by a flavin cofactor. In spite of ...

    In mammals, xanthine oxidoreductase can exist as xanthine dehydrogenase (XDH) and xanthine oxidase (XO). The two enzymes possess common redox active cofactors, which form an electron transfer (ET) pathway terminated by a flavin cofactor. In spite of identical protein primary structures, the redox potential difference between XDH and XO for the flavin semiquinone/hydroquinone pair (E(sq/hq)) is ~170 mV, a striking difference. The former greatly prefers NAD(+) as ultimate substrate for ET from the iron-sulfur cluster FeS-II via flavin while the latter only accepts dioxygen. In XDH (without NAD(+)), however, the redox potential of the electron donor FeS-II is 180 mV higher than that for the acceptor flavin, yielding an energetically uphill ET. On the basis of new 1.65, 2.3, 1.9, and 2.2 Å resolution crystal structures for XDH, XO, the NAD(+)- and NADH-complexed XDH, E(sq/hq) were calculated to better understand how the enzyme activates an ET from FeS-II to flavin. The majority of the E(sq/hq) difference between XDH and XO originates from a conformational change in the loop at positions 423-433 near the flavin binding site, causing the differences in stability of the semiquinone state. There was no large conformational change observed in response to NAD(+) binding at XDH. Instead, the positive charge of the NAD(+) ring, deprotonation of Asp429, and capping of the bulk surface of the flavin by the NAD(+) molecule all contribute to altering E(sq/hq) upon NAD(+) binding to XDH.


    Organizational Affiliation

    Career-Path Promotion Unit for Young Life Scientists, Kyoto University, 202 Building E, Graduate School of Medicine, Kyoto 606-8501, Japan. hiro@cp.kyoto-u.ac.jp



Macromolecules
Find similar proteins by:  (by identity cutoff)  |  Structure
Entity ID: 1
MoleculeChainsSequence LengthOrganismDetailsImage
Xanthine dehydrogenase/oxidaseA, B1332Bos taurusMutation(s): 0 
Gene Names: XDH
EC: 1.17.1.4 (PDB Primary Data), 1.17.3.2 (PDB Primary Data)
Find proteins for P80457 (Bos taurus)
Explore P80457 
Go to UniProtKB:  P80457
Protein Feature View
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  • Reference Sequence
Small Molecules
Ligands 8 Unique
IDChainsName / Formula / InChI Key2D Diagram3D Interactions
FAD
Query on FAD

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A, B
FLAVIN-ADENINE DINUCLEOTIDE
C27 H33 N9 O15 P2
VWWQXMAJTJZDQX-UYBVJOGSSA-N
 Ligand Interaction
MTE
Query on MTE

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A, B
PHOSPHONIC ACIDMONO-(2-AMINO-5,6-DIMERCAPTO-4-OXO-3,7,8A,9,10,10A-HEXAHYDRO-4H-8-OXA-1,3,9,10-TETRAAZA-ANTHRACEN-7-YLMETHYL)ESTER
C10 H14 N5 O6 P S2
HPEUEJRPDGMIMY-IFQPEPLCSA-N
 Ligand Interaction
FES
Query on FES

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A, B
FE2/S2 (INORGANIC) CLUSTER
Fe2 S2
NIXDOXVAJZFRNF-UHFFFAOYSA-N
 Ligand Interaction
MOS
Query on MOS

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A, B
DIOXOTHIOMOLYBDENUM(VI) ION
H Mo O2 S
BDSRWPHSAKXXRG-UHFFFAOYSA-M
 Ligand Interaction
SAL
Query on SAL

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A, B
2-HYDROXYBENZOIC ACID
C7 H6 O3
YGSDEFSMJLZEOE-UHFFFAOYSA-N
 Ligand Interaction
GOL
Query on GOL

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A, B
GLYCEROL
C3 H8 O3
PEDCQBHIVMGVHV-UHFFFAOYSA-N
 Ligand Interaction
CO3
Query on CO3

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A, B
CARBONATE ION
C O3
BVKZGUZCCUSVTD-UHFFFAOYSA-L
 Ligand Interaction
CA
Query on CA

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A, B
CALCIUM ION
Ca
BHPQYMZQTOCNFJ-UHFFFAOYSA-N
 Ligand Interaction
Experimental Data & Validation

Experimental Data

  • Method: X-RAY DIFFRACTION
  • Resolution: 1.65 Å
  • R-Value Free: 0.196 
  • R-Value Work: 0.177 
  • Space Group: C 1 2 1
Unit Cell:
Length ( Å )Angle ( ˚ )
a = 167.573α = 90
b = 124.37β = 91.02
c = 148.177γ = 90
Software Package:
Software NamePurpose
CNSrefinement
HKL-2000data reduction
HKL-2000data scaling
CNSphasing

Structure Validation

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Entry History 

Deposition Data

Revision History 

  • Version 1.0: 2012-05-09
    Type: Initial release