https://scholars.lib.ntu.edu.tw/handle/123456789/143324
標題: | pH-profile crystal structure studies of C-terminal despentapeptide nitrite reductase from Achromobacter cycloclastes | 作者: | Li, Hai-Tao Wang, Chao Chang, Tschining Chang, Wen-Chang Liu, Ming-Yih Gall, Jean Le Gui, Lu-lu Zhang, Ji-Ping An, Xiao-Min Chang, Wen-Rui |
關鍵字: | Crystal structure;Denitrification;Nitrite reductase;Residue deletion;pH profile;Achromobacter cycloclastes | 公開日期: | 15-一月-2004 | 出版社: | Taipei:National Taiwan University Dept Chem Engn | 起(迄)頁: | - | 來源出版物: | Biochemical & Biophysical Research Communications 316, 107–113 | 摘要: | Crystal structures of C-terminal despentapeptide nitrite reductase (NiRc-5) from Achromobacter cycloclastes were determined from 1.9 to 2.3A at pH 5.0, 5.4, & 6.2. NiRc-5, that has lost about 30% activity, is found to possess quite similar trimeric structures as the native enzyme. Electron density & copper content measurements indicate that the activity loss is not caused by the release of type 2 copper (T2Cu). pH-profile structural comparisons with native enzyme reveal that the T2Cu active center in NiRc-5 is perturbed, accounting for the partial loss of enzyme activity. This perturbation likely results from the less constrained conformations of two catalytic residues, Asp98 & His255. Hydrogen bonding analysis shows that the deletion of five residues causes a loss of more than half the intersubunit hydrogen bonds mediated by C-terminal tail. This study shows that the C-terminal tail plays an important role in controlling the conformations around the T2Cu site at the subunit interface, & helps keep the optimum microenvironment of active center for the full enzyme activity of AcNiR. Crystal structures of C-terminal despentapeptide nitrite reductase (NiRc-5) from Achromobacter cycloclastes were determined from 1.9 to 2.3A at pH 5.0, 5.4, and 6.2. NiRc-5, that has lost about 30% activity, is found to possess quite similar trimeric structures as the native enzyme. Electron density and copper content measurements indicate that the activity loss is not caused by the release of type 2 copper (T2Cu). pH-profile structural comparisons with native enzyme reveal that the T2Cu active center in NiRc-5 is perturbed, accounting for the partial loss of enzyme activity. This perturbation likely results from the less constrained conformations of two catalytic residues, Asp98 and His255. Hydrogen bonding analysis shows that the deletion of five residues causes a loss of more than half the intersubunit hydrogen bonds mediated by C-terminal tail. This study shows that the C-terminal tail plays an important role in controlling the conformations around the T2Cu site at the subunit interface, and helps keep the optimum microenvironment of active center for the full enzyme activity of AcNiR. |
URI: | http://ntur.lib.ntu.edu.tw//handle/246246/2006111501265135 | 其他識別: | 246246/2006111501265135 | DOI: | 10.1016/j.bbrc.2004.01.177 |
顯示於: | 生化科學研究所 |
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