1PL4 image
Deposition Date 2003-06-06
Release Date 2003-12-16
Last Version Date 2023-08-16
Entry Detail
PDB ID:
1PL4
Keywords:
Title:
Crystal Structure of human MnSOD Y166F mutant
Biological Source:
Source Organism:
Homo sapiens (Taxon ID: 9606)
Host Organism:
Method Details:
Experimental Method:
Resolution:
1.47 Å
R-Value Free:
0.23
R-Value Work:
0.18
R-Value Observed:
0.2
Space Group:
P 21 21 21
Macromolecular Entities
Polymer Type:polypeptide(L)
Molecule:Superoxide dismutase [Mn], mitochondrial
Gene (Uniprot):SOD2
Mutations:Y166F
Chain IDs:A, B, C, D
Chain Length:198
Number of Molecules:4
Biological Source:Homo sapiens
Ligand Molecules
Primary Citation
Amino acid substitution at the dimeric interface of human manganese superoxide dismutase
J.Biol.Chem. 279 5861 5866 (2004)
PMID: 14638684 DOI: 10.1074/jbc.M311310200

Abstact

The side chains of His30 and Tyr166 from adjacent subunits in the homotetramer human manganese superoxide dismutase (Mn-SOD) form a hydrogen bond across the dimer interface and participate in a hydrogen-bonded network that extends to the active site. Compared with wild-type Mn-SOD, the site-specific mutants H30N, Y166F, and the corresponding double mutant showed 10-fold decreases in steady-state constants for catalysis measured by pulse radiolysis. The observation of no additional effect upon the second mutation is an example of cooperatively interacting residues. A similar effect was observed in the thermal stability of these enzymes; the double mutant did not reduce the major unfolding transition to an extent greater than either single mutant. The crystal structures of these site-specific mutants each have unique conformational changes, but each has lost the hydrogen bond across the dimer interface, which results in a decrease in catalysis. These same mutations caused an enhancement of the dissociation of the product-inhibited complex. That is, His30 and Tyr166 in wild-type Mn-SOD act to prolong the lifetime of the inhibited complex. This would have a selective advantage in blocking a cellular overproduction of toxic H2O2.

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