1EM1

X-RAY CRYSTAL STRUCTURE FOR HUMAN MANGANESE SUPEROXIDE DISMUTASE, Q143A


Experimental Data Snapshot

  • Method: X-RAY DIFFRACTION
  • Resolution: 2.13 Å
  • R-Value Free: 0.264 
  • R-Value Work: 0.232 
  • R-Value Observed: 0.232 

wwPDB Validation   3D Report Full Report


This is version 1.3 of the entry. See complete history


Literature

Multiple replacements of glutamine 143 in human manganese superoxide dismutase: effects on structure, stability, and catalysis.

Leveque, V.J.Stroupe, M.E.Lepock, J.R.Cabelli, D.E.Tainer, J.A.Nick, H.S.Silverman, D.N.

(2000) Biochemistry 39: 7131-7137

  • DOI: 10.1021/bi9929958
  • Primary Citation of Related Structures:  
    1EM1

  • PubMed Abstract: 
  • Glutamine 143 in human manganese superoxide dismutase (MnSOD) forms a hydrogen bond with the manganese-bound solvent molecule and is investigated by replacement using site-specific mutagenesis. Crystal structures showed that the replacement of Gln 14 ...

    Glutamine 143 in human manganese superoxide dismutase (MnSOD) forms a hydrogen bond with the manganese-bound solvent molecule and is investigated by replacement using site-specific mutagenesis. Crystal structures showed that the replacement of Gln 143 with Ala made no significant change in the overall structure of the mutant enzyme. Two new water molecules in Q143A MnSOD were situated in positions nearly identical with the Oepsilon1 and Nepsilon2 of the replaced Gln 143 side chain and maintained a hydrogen-bonded network connecting the manganese-bound solvent molecule to other residues in the active site. However, their presence could not sustain the stability and activity of the enzyme; the main unfolding transition of Q143A was decreased 16 degrees C and its catalysis decreased 250-fold to k(cat)/K(m) = 3 x 10(6) M(-)(1) s(-)(1), as determined by stopped-flow spectrophotometry and pulse radiolysis. The mutant Q143A MnSOD and other mutants at position 143 showed very low levels of product inhibition and favored Mn(II)SOD in the resting state, whereas the wild type showed strong product inhibition and favored Mn(III)SOD. However, these differences did not affect the rate constant for dissociation of the product-inhibited complex in Q143A MnSOD which was determined from a characteristic absorbance at 420 nm and was comparable in magnitude ( approximately 100 s(-)(1)) to that of the wild-type enzyme. Hence, Gln 143, which is necessary for maximal activity in superoxide dismutation, appears to have no role in stabilization and dissociation of the product-inhibited complex.


    Related Citations: 
    • The Structure of Human Mitochondrial Manganese Superoxide Dismutase Reveals a Novel Tetrameric Interface of Two 4-Helix Bundles
      Borgstahl, G.E., Parge, H.E., Hickey, M.J., Beyer Junior, W.F., Hallewell, R.A., Tainer, J.A.
      (1993) Cell 71: 107

    Organizational Affiliation

    Department of Pharmacology, Biochemistry, and Neuroscience, University of Florida, Gainesville 32610, USA.



Macromolecules
Find similar proteins by:  (by identity cutoff)  |  Structure
Entity ID: 1
MoleculeChainsSequence LengthOrganismDetailsImage
MANGANESE SUPEROXIDE DISMUTASEAB198Homo sapiensMutation(s): 1 
Gene Names: SOD2
EC: 1.15.1.1
Find proteins for P04179 (Homo sapiens)
Explore P04179 
Go to UniProtKB:  P04179
NIH Common Fund Data Resources
PHAROS  P04179
Protein Feature View
Expand
  • Reference Sequence
Small Molecules
Ligands 2 Unique
IDChainsName / Formula / InChI Key2D Diagram3D Interactions
SO4
Query on SO4

Download CCD File 
A, B
SULFATE ION
O4 S
QAOWNCQODCNURD-UHFFFAOYSA-L
 Ligand Interaction
MN
Query on MN

Download CCD File 
A, B
MANGANESE (II) ION
Mn
WAEMQWOKJMHJLA-UHFFFAOYSA-N
 Ligand Interaction
Experimental Data & Validation

Experimental Data

  • Method: X-RAY DIFFRACTION
  • Resolution: 2.13 Å
  • R-Value Free: 0.264 
  • R-Value Work: 0.232 
  • R-Value Observed: 0.232 
  • Space Group: P 61 2 2
Unit Cell:
Length ( Å )Angle ( ˚ )
a = 79.643α = 90
b = 79.643β = 90
c = 241.642γ = 120
Software Package:
Software NamePurpose
AMoREphasing
CNSrefinement
MAR345data collection
SCALEPACKdata scaling

Structure Validation

View Full Validation Report



Entry History 

Deposition Data

Revision History 

  • Version 1.0: 2000-03-24
    Type: Initial release
  • Version 1.1: 2008-04-27
    Changes: Version format compliance
  • Version 1.2: 2011-07-13
    Changes: Derived calculations, Version format compliance
  • Version 1.3: 2017-10-04
    Changes: Refinement description