PDBsum entry 4l2a

Oxidoreductase

PDB id: 4l2a

Contents

Protein chains

192 a.a.

Metals

_FE ×2

Waters ×336

PDB id:

4l2a

Name:

Oxidoreductase

Title:

X-ray structure of the c57r mutant of the iron superoxide dismutase from pseudoalteromonas haloplanktis (crystal form ii)

Structure:

Superoxide dismutase [fe]. Chain: a, b. Engineered: yes. Mutation: yes

Source:

Pseudoalteromonas haloplanktis. Organism_taxid: 228. Gene: sodb, pshaa1215. Expressed in: escherichia coli. Expression_system_taxid: 562

Resolution:

2.06Å R-factor: 0.190 R-free: 0.240

Authors:

A.Merlino,I.Russo Krauss,F.Sica

Key ref:

A.Merlino et al. (2014). Structural and denaturation studies of two mutants of a cold adapted superoxide dismutase point to the importance of electrostatic interactions in protein stability. Biochim Biophys Acta, 1844, 632-640. PubMed id: 24440460 DOI: 10.1016/j.bbapap.2014.01.007

Date:

04-Jun-13 Release date: 26-Feb-14

Protein chains

P84612  (SODF_PSEHT) -  Superoxide dismutase [Fe] from Pseudoalteromonas translucida (strain TAC 125)

Seq: 192 a.a.

Struc: 192 a.a.*

* PDB and UniProt seqs differ at 1 residue position (black cross)

Enzyme reactions

• Enzyme class: E.C.1.15.1.1 - superoxide dismutase.
• Reaction: 2 superoxide + 2 H⁺ = H2O2 + O2
• Cofactor: Fe cation or Mn(2+) or (Zn(2+) and Cu cation)

Molecule diagrams generated from .mol files obtained from the KEGG ftp site

Added reference

DOI no: 10.1016/j.bbapap.2014.01.007

Biochim Biophys Acta 1844:632-640 (2014)

PubMed id: 24440460

Structural and denaturation studies of two mutants of a cold adapted superoxide dismutase point to the importance of electrostatic interactions in protein stability.

A.Merlino, I.Russo Krauss, I.Castellano, M.R.Ruocco, A.Capasso, E.De Vendittis, B.Rossi, F.Sica.

ABSTRACT

A peculiar feature of the psychrophilic iron superoxide dismutase from Pseudoalteromonas haloplanktis (PhSOD) is the presence in its amino acid sequence of a reactive cysteine (Cys57). To define the role of this residue, a structural characterization of the effect of two PhSOD mutations, C57S and C57R, was performed. Thermal and denaturant-induced unfolding of wild type and mutant PhSOD followed by circular dichroism and fluorescence studies revealed that C→R substitution alters the thermal stability and the resistance against denaturants of the enzyme, whereas C57S only alters the stability of the protein against urea. The crystallographic data on the C57R mutation suggest an involvement of the Arg side chain in the formation of salt bridges on protein surface. These findings support the hypothesis that the thermal resistance of PhSOD relies on optimization of charge-charge interactions on its surface. Our study contributes to a deeper understanding of the denaturation mechanism of superoxide dismutases, suggesting the presence of a structural dimeric intermediate between the native state and the unfolded state. This hypothesis is supported by the crystalline and solution data on the reduced form of the enzyme.