InterPro domain: IPR036314

Superoxide dismutases (SODs) ( 1.15.1.1 ) catalyse the conversion of superoxide radicals to molecular oxygen. Their function is to destroy the radicals that are normally produced within cells and are toxic to biological systems. Three evolutionarily distinct families of SODs are known, of which the Mn/Fe-binding family is one [ 1 , 2 , 3 ]. This family includes both single metal-binding SODs and cambialistic SOD, which can bind either Mn or Fe. Fe/MnSODs are ubiquitous enzymes that are responsible for the majority of SOD activity in prokaryotes, fungi, blue-green algae and mitochondria. Fe/MnSODs are found as homodimers or homotetramers.

The structure of Fe/MnSODs can be divided into two domains, an alpha N-terminal domain and an alpha/beta C-terminal domain, connected by a loop. The structure of the N-terminal domain consists of a two helices in an antiparallel hairpin, with a left-handed twist [ 4 ]. The structure of the C-terminal domain is of the alpha/beta type, and consists of a three-stranded antiparallel beta-sheet in the order 213, along with four helices in the arrangement alpha/beta(2)/alpha/beta/alpha(2) [ 5 ].

This superfamily describes the C-terminal domain of Manganese/iron superoxide dismutase.

1. Aspects of the structure, function, and applications of superoxide dismutase. CRC Crit. Rev. Biochem. 22, 111-80
2. Iron- and manganese-containing superoxide dismutases can be distinguished by analysis of their primary structures. FEBS Lett. 229, 377-82
3. A comparison of evolutionary rates of the two major kinds of superoxide dismutase. J. Mol. Evol. 34, 175-84
4. Crystal structure of Y34F mutant human mitochondrial manganese superoxide dismutase and the functional role of tyrosine 34. Biochemistry 37, 4722-30
5. Iron superoxide dismutase from the archaeon Sulfolobus solfataricus: analysis of structure and thermostability. J. Mol. Biol. 286, 189-205