1BA9

THE SOLUTION STRUCTURE OF REDUCED MONOMERIC SUPEROXIDE DISMUTASE, NMR, 36 STRUCTURES


Experimental Data Snapshot

  • Method: SOLUTION NMR
  • Conformers Calculated: 36 
  • Conformers Submitted: 36 
  • Selection Criteria: target function 

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This is version 1.2 of the entry. See complete history


Literature

Solution structure of reduced monomeric Q133M2 copper, zinc superoxide dismutase (SOD). Why is SOD a dimeric enzyme?.

Banci, L.Benedetto, M.Bertini, I.Del Conte, R.Piccioli, M.Viezzoli, M.S.

(1998) Biochemistry 37: 11780-11791

  • DOI: 10.1021/bi9803473
  • Primary Citation of Related Structures:  
    1BA9

  • PubMed Abstract: 
  • Copper, zinc superoxide dismutase is a dimeric enzyme, and it has been shown that no cooperativity between the two subunits of the dimer is operative. The substitution of two hydrophobic residues, Phe 50 and Gly 51, with two Glu's at the interface region has disrupted the quaternary structure of the protein, thus producing a soluble monomeric form ...

    Copper, zinc superoxide dismutase is a dimeric enzyme, and it has been shown that no cooperativity between the two subunits of the dimer is operative. The substitution of two hydrophobic residues, Phe 50 and Gly 51, with two Glu's at the interface region has disrupted the quaternary structure of the protein, thus producing a soluble monomeric form. However, this monomeric form was found to have an activity lower than that of the native dimeric species (10%). To answer the fundamental question of the role of the quaternary structure in the catalytic process of superoxide dismutase, we have determined the solution structure of the reduced monomeric mutant through NMR spectroscopy. Another fundamental issue with respect to the enzymatic mechanism is the coordination of reduced copper, which is the active center. The three-dimensional solution structure of this 153-residue monomeric form of SOD (16 kDa) has been determined using distance and dihedral angle constraints obtained from 13C, 15N triple-resonance NMR experiments. The solution structure is represented by a family of 36 structures, with a backbone rmsd of 0.81 +/- 0.13 A over residues 3-150 and of 0.56 +/- 0.08 A over residues 3-49 and 70-150. This structure has been compared with the available X-ray structures of reduced SODs as well as with the oxidized form of human and bovine isoenzymes. The structure contains the classical eight-stranded Greek key beta-barrel. In general, the backbone and the metal sites are not affected much by the monomerization, except in the region involved in the subunit-subunit interface in the dimeric protein, where a large disorder is present. Significative changes are observed in the conformation of the electrostatic loop, which forms one side of the active site channel and which is fundamental in determining the optimal electrostatic potential for driving the superoxide anions to the copper site which is the rate-limiting step of the enymatic reaction under nonsaturating conditions. In the present monomer, its conformation is less favorable for the diffusion of the substrate to the reaction site. The structure of the copper center is well-defined; copper(I) is coordinated to three histidines, at variance with copper(II) which is bound to four histidines. The hydrogen atom which binds the histidine nitrogen detached from copper(I) is structurally identified.


    Organizational Affiliation

    Department of Chemistry, University of Florence, Italy.



Macromolecules
Find similar proteins by:  (by identity cutoff)  |  Structure
Entity ID: 1
MoleculeChainsSequence LengthOrganismDetailsImage
SUPEROXIDE DISMUTASEA153Homo sapiensMutation(s): 5 
Gene Names: HSODSOD1
EC: 1.15.1.1
UniProt & NIH Common Fund Data Resources
Find proteins for P00441 (Homo sapiens)
Explore P00441 
Go to UniProtKB:  P00441
PHAROS:  P00441
Protein Feature View
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  • Reference Sequence
Small Molecules
Ligands 2 Unique
IDChainsName / Formula / InChI Key2D Diagram3D Interactions
ZN
Query on ZN

Download Ideal Coordinates CCD File 
B [auth A]ZINC ION
Zn
PTFCDOFLOPIGGS-UHFFFAOYSA-N
 Ligand Interaction
CU1
Query on CU1

Download Ideal Coordinates CCD File 
C [auth A]COPPER (I) ION
Cu
VMQMZMRVKUZKQL-UHFFFAOYSA-N
 Ligand Interaction
Experimental Data & Validation

Experimental Data

  • Method: SOLUTION NMR
  • Conformers Calculated: 36 
  • Conformers Submitted: 36 
  • Selection Criteria: target function 
  • OLDERADO: 1BA9 Olderado

Structure Validation

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Entry History 

Deposition Data

Revision History  (Full details and data files)

  • Version 1.0: 1998-09-16
    Type: Initial release
  • Version 1.1: 2008-03-24
    Changes: Version format compliance
  • Version 1.2: 2011-07-13
    Changes: Version format compliance