1IL0

X-RAY CRYSTAL STRUCTURE OF THE E170Q MUTANT OF HUMAN L-3-HYDROXYACYL-COA DEHYDROGENASE


Experimental Data Snapshot

  • Method: X-RAY DIFFRACTION
  • Resolution: 2.20 Å
  • R-Value Free: 0.276 
  • R-Value Work: 0.219 
  • R-Value Observed: 0.219 

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Ligand Structure Quality Assessment 


This is version 1.3 of the entry. See complete history


Literature

Glutamate 170 of human l-3-hydroxyacyl-CoA dehydrogenase is required for proper orientation of the catalytic histidine and structural integrity of the enzyme.

Barycki, J.J.O'Brien, L.K.Strauss, A.W.Banaszak, L.J.

(2001) J Biol Chem 276: 36718-36726

  • DOI: 10.1074/jbc.M104839200
  • Primary Citation of Related Structures:  
    1IL0

  • PubMed Abstract: 
  • l-3-Hydroxyacyl-CoA dehydrogenase (HAD), the penultimate enzyme in the beta-oxidation spiral, reversibly catalyzes the conversion of l-3-hydroxyacyl-CoA to the corresponding 3-ketoacyl-CoA. Similar to other dehydrogenases, HAD contains a general acid/base, His(158), which is within hydrogen bond distance of a carboxylate, Glu(170) ...

    l-3-Hydroxyacyl-CoA dehydrogenase (HAD), the penultimate enzyme in the beta-oxidation spiral, reversibly catalyzes the conversion of l-3-hydroxyacyl-CoA to the corresponding 3-ketoacyl-CoA. Similar to other dehydrogenases, HAD contains a general acid/base, His(158), which is within hydrogen bond distance of a carboxylate, Glu(170). To investigate its function in this catalytic dyad, Glu(170) was replaced with glutamine (E170Q), and the mutant enzyme was characterized. Whereas substrate and cofactor binding were unaffected by the mutation, E170Q exhibited diminished catalytic activity. Protonation of the catalytic histidine did not restore wild-type activity, indicating that modulation of the pK(a) of His(158) is not the sole function of Glu(170). The pH profile of charge transfer complex formation, an independent indicator of active site integrity, was unaltered by the amino acid substitution, but the intensity of the charge transfer band was diminished. This observation, coupled with significantly reduced enzymatic stability of the E170Q mutant, implicates Glu(170) in maintenance of active site architecture. Examination of the crystal structure of E170Q in complex with NAD(+) and acetoacetyl-CoA (R = 21.9%, R(free) = 27.6%, 2.2 A) reveals that Gln(170) no longer hydrogen bonds to the side chain of His(158). Instead, the imidazole ring is nearly perpendicular to its placement in the comparable native complex and no longer positioned for efficient catalysis.


    Related Citations: 
    • Sequestration of the Active Site by Interdomain Shifting. CRYSTALLOGRAPHIC AND SPECTROSCOPIC EVIDENCE FOR DISTINCT CONFORMATIONS OF L-3-HYDROXYACYL-CoA DEHYDROGENASE
      Barycki, J.J., O'Brien, L.K., Strauss, A.W., BANASZAK, L.J.
      (2000) J Biol Chem 275: 27186

    Organizational Affiliation

    Department of Biochemistry, Molecular Biology, and Biophysics, University of Minnesota, Minneapolis, Minnesota 55455, USA.



Macromolecules
Find similar proteins by:  (by identity cutoff)  |  Structure
Entity ID: 1
MoleculeChainsSequence LengthOrganismDetailsImage
3-hydroxyacyl-CoA dehydrogenaseA, B302Homo sapiensMutation(s): 1 
Gene Names: HCDHHADHHADHAD1HADHSCSCHAD
EC: 1.1.1.35
UniProt & NIH Common Fund Data Resources
Find proteins for Q16836 (Homo sapiens)
Explore Q16836 
Go to UniProtKB:  Q16836
PHAROS:  Q16836
Protein Feature View
Expand
  • Reference Sequence
Small Molecules
Ligands 2 Unique
IDChainsName / Formula / InChI Key2D Diagram3D Interactions
CAA (Subject of Investigation/LOI)
Query on CAA

Download Ideal Coordinates CCD File 
C [auth A], E [auth B]ACETOACETYL-COENZYME A
C25 H40 N7 O18 P3 S
OJFDKHTZOUZBOS-CITAKDKDSA-N
 Ligand Interaction
NAD (Subject of Investigation/LOI)
Query on NAD

Download Ideal Coordinates CCD File 
D [auth A], F [auth B]NICOTINAMIDE-ADENINE-DINUCLEOTIDE
C21 H27 N7 O14 P2
BAWFJGJZGIEFAR-NNYOXOHSSA-N
 Ligand Interaction
Experimental Data & Validation

Experimental Data

  • Method: X-RAY DIFFRACTION
  • Resolution: 2.20 Å
  • R-Value Free: 0.276 
  • R-Value Work: 0.219 
  • R-Value Observed: 0.219 
  • Space Group: P 21 21 21
Unit Cell:
Length ( Å )Angle ( ˚ )
a = 49.657α = 90
b = 87.719β = 90
c = 158.395γ = 90
Software Package:
Software NamePurpose
CNSrefinement
CrystalCleardata reduction
CrystalCleardata scaling
CNSphasing

Structure Validation

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Ligand Structure Quality Assessment  



Entry History 

Deposition Data

Revision History  (Full details and data files)

  • Version 1.0: 2001-11-07
    Type: Initial release
  • Version 1.1: 2008-04-27
    Changes: Version format compliance
  • Version 1.2: 2011-07-13
    Changes: Version format compliance
  • Version 1.3: 2018-04-04
    Changes: Data collection