Structure, stability and flexibility of a psychrophilic iron superoxide dismutase

Superoxide dismutase Superoxide dismutase

On the Stability of Bovine Superoxide Dismutase

1. Apo-superoxide dismutase was more labile toward a variety of inactivating stresses than was the holoenzyme. 2. cu++ restored catalytic activity to the apoenzyme and markedly enhanced its thermal stability but Cu++ plus Zn++ were needed to attain the stability of the native enzyme. 3. Co’-+ or Hgii were able to replace Zn++ in increasing the thermal stability of the Cu+f-repleted apoenzyme. I...

Nickel superoxide dismutase structure and mechanism.

The 1.30 A resolution crystal structure of nickel superoxide dismutase (NiSOD) identifies a novel SOD fold, assembly, and Ni active site. NiSOD is a hexameric assembly of right-handed 4-helix bundles of up-down-up-down topology with N-terminal hooks chelating the active site Ni ions. This newly identified nine-residue Ni-hook structural motif (His-Cys-X-X-Pro-Cys-Gly-X-Tyr) provides almost all ...

Subunit structure of human superoxide dismutase.

A subunit structure for human superoxide dismutase has been demonstrated by sedimentation equilibrium, agarose gel filtration, and sodium dodecyl sulfate polyacrylamide gel electrophoretic studies. This protein appears to be composed of 2 subunits, not linked by covalent bonds, each with a molecular weight about 16,000. Dissociation of the subunits is facilitated by alkylation of the two sulfhy...

A tetrameric iron superoxide dismutase from the eucaryote Tetrahymena pyriformis.

An iron-containing superoxide dismutase has been purified from the protozoan Tetrahymena pyriformis. It has a molecular weight of 85,000 and is composed of four subunits of equal size. The tetramer contains 2.5 g atoms of ferric iron. Visible absorption and electron spin resonance spectra closely resemble those of other iron-containing superoxide dismutases. The amino acid sequence of the iron ...