5X1Y

Structure of mercuric reductase from Lysinibacillus sphaericus

5X1Y の概要

• エントリーDOI: 10.2210/pdb5x1y/pdb
• 分子名称: Mercuric reductase, FLAVIN-ADENINE DINUCLEOTIDE (2 entities in total)
• 機能のキーワード: mercuric reductase, mera, fad, oxidoreductase
• 由来する生物種: Lysinibacillus sphaericus
• タンパク質・核酸の鎖数: 6
• 化学式量合計: 363908.55

構造登録者

Khan, F.,Suguna, K. (登録日: 2017-01-28, 公開日: 2017-10-04, 最終更新日: 2024-11-06)

主引用文献

Bafana, A.,Khan, F.,Suguna, K.
Structural and functional characterization of mercuric reductase from Lysinibacillus sphaericus strain G1.
Biometals, 30:809-819, 2017

PubMed Abstract: In response to the widespread presence of inorganic Hg in the environment, bacteria have evolved resistance systems with mercuric reductase (MerA) as the key enzyme. MerA enzymes have still not been well characterized from gram positive bacteria. Current study reports physico-chemical, kinetic and structural characterization of MerA from a multiple heavy metal resistant strain of Lysinibacillus sphaericus, and discusses its implications in bioremediation application. The enzyme was homodimeric with subunit molecular weight of about 60 kDa. The K and V were found to be 32 µM of HgCl and 18 units/mg respectively. The enzyme activity was enhanced by β-mercaptoethanol and NaCl up to concentrations of 500 µM and 100 mM respectively, followed by inhibition at higher concentrations. The enzyme showed maximum activity in the pH range of 7-7.5 and temperature range of 25-50 °C, with melting temperature of 67 °C. Cu exhibited pronounced inhibition of the enzyme with mixed inhibition pattern. The enzyme contained FAD as the prosthetic group and used NADPH as the preferred electron donor, but it showed slight activity with NADH as well. Structural characterization was carried out by circular dichroism spectrophotometry and X-ray crystallography. X-ray confirmed the homodimeric structure of enzyme and gave an insight on the residues involved in catalytic binding. In conclusion, the investigated enzyme showed higher catalytic efficiency, temperature stability and salt tolerance as compared to MerA enzymes from other mesophiles. Therefore, it is proposed to be a promising candidate for Hg bioremediation.

PubMed: 28894951
DOI: 10.1007/s10534-017-0050-x

実験手法

X-RAY DIFFRACTION (3.48 Å)