Secondary structure dependent on metal ions of copper,zinc superoxide dismutase investigated by Fourier transform IR spectroscopy.
Copper, zinc superoxide dismutase (Cu2Zn2-SOD) from bovine erythrocyte and its metal ion free derivatives, E2Zn2-SOD, Cu2E2-SOD, and E2E2-SOD (E: empty) were prepared and their secondary structures were investigated by Fourier transform ir spectroscopy. In 20 mM deuterated phosphate buffer (pD 7.5) solution at room temperature, the native Cu2Zn2-SOD contains about 34% beta-strand, 17% beta-turn, and 49% unordered structures, which is similar to the content determined by x-ray crystal structural analysis. The metal ion free derivatives decrease the component of beta-strand and increase the unordered structure component in trend. Especially in the cases of zinc-free derivatives, Cu2E2-SOD and E2E2-SOD, about 24% beta-strand, 20% beta-turn, and 57% unordered structures are obtained. The result indicates that the zinc ion plays an important role in determining the secondary structure of copper,zinc superoxide dismutase.
Sun
W Y
WY
State Key Laboratory of Coordination Chemistry, Nanjing University, China.
Fang
J L
JL
Cheng
M
M
Xia
P Y
PY
Tang
W X
WX
D000818:Animals; D001051:Apoenzymes / Q000737:chemistry; D002417:Cattle; D017666:Deuterium Oxide; D004912:Erythrocytes / Q000201:enzymology; D017433:Protein Structure, Secondary; D017550:Spectroscopy, Fourier Transform Infrared; D013482:Superoxide Dismutase / Q000737:chemistry*
D001051:Apoenzymes; D013482:Superoxide Dismutase; D017666:Deuterium Oxide