Comparison of Protein-water Interactions in Psychrophilic, Mesophilic, and Thermophilic Fe-SOD
Zhaolin Mou, Yanrui Ding, Xueqin Wang and Yujie Cai
Affiliation: No.1800, Lihu Road, Jiangnan University, Wuxi, Jiangsu PR, China.
Iron superoxide dismutase (Fe-SOD) can eliminate superoxide anion radicals and is widely used in pharmaceuticals,
cosmetics and foodstuff. It’s significant to determine the factors that influence Fe-SOD thermostability. Previous
studies have focused on the relationship between the structural parameters and thermostability of Fe-SOD while the contribution
of water molecules was overlooked. In this study, we examined the relationship between hydration waters and
Fe-SOD thermostability. The Voronoi polyhedra method was used to explore the distribution of hydration waters around
the Fe-SODs and it was interesting to find that the distribution of hydration waters is related to the B-factor of amino acids,
i.e., the flexibility of residues can affect the distribution of waters. Protein-water and water-water hydrogen bonds
were examined. We found that the hydrogen bond density in thermophilic Fe-SOD was higher than that in mesophilic Fe-
SOD. In addition, larger hydrogen bond networks that involve more waters covered the thermophilic Fe-SOD.
Keywords: Hydration waters, hydrogen bond network, iron superoxide dismutase, protein thermostability, temperature factor,
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