Structure of a superoxide dismutase and implications for copper-ion chelation

• Published in: Acta crystallographica. Section D, Biological crystallography. Biological crystallography., 2008-08, Vol.64 (8), p.892-901
• Main Authors: Yogavel, Manickam, Mishra, Prakash Chandra, Gill, Jasmita, Bhardwaj, Pardeep Kumar, Dutt, Som, Kumar, Sanjay, Ahuja, Paramvir Singh, Sharma, Amit
• Format: Article
• Language: English
• Subjects: Amino Acid Sequence; Binding Sites; Cations - chemistry; Copper - chemistry; copper binding; Crystallography, X-Ray; Dimerization; dismutases; Enzyme Stability; free radicals; high altitude; Hydrogen Bonding; Models, Molecular; Molecular Sequence Data; Plant Proteins - chemistry; Potentilla - enzymology; Sequence Homology, Amino Acid; Static Electricity; Superoxide Dismutase - chemistry; Temperature; thermostability; Water - chemistry
• ISSN: 1399-0047; 0907-4449; 1399-0047
• DOI: 10.1107/S0907444908019069

Superoxide dismutase (SOD) plays a central role in cellular defence against oxidative stress and is of pharmaceutical importance. The SOD from Potentilla atrosanguinea (Pa‐SOD) is a unique enzyme as it possesses free‐radical scavenging capability at temperatures ranging between 263 and 353 K. The crystal structure of recombinant Pa‐SOD has been determined to 2.3 Å resolution. The active‐site residues are well ordered and additional water molecules are present in place of a bound copper ion. There is a significant difference in the relative orientation of the two subunits of Pa‐SOD and asymmetry is also present in numerous hydrogen‐bonding interactions. Structures of SODs, both bound with copper and unbound, have been compared with respect to the orientation of the electrostatic and Greek‐key loops. This analysis provides new insights into the copper‐chelation process in SODs. Several new structural features in Pa‐SOD which may be responsible for its unique properties of thermostability and expanded range of antioxidant activity are also highlighted.