果胶酸裂解酶
裂解酶
化学
螺旋(腹足类)
钙
基质(水族馆)
分子置换
结晶学
EF手
蛋白质结构
晶体结构
立体化学
酶
生物化学
果胶酶
钙调蛋白
生物
有机化学
蜗牛
生态学
作者
M. Akita,Atsuo Suzuki,Tohru Kobayashi,Susumu Ito,Takashi Yamane
出处
期刊:Acta Crystallographica Section D-biological Crystallography
[International Union of Crystallography]
日期:2001-11-21
卷期号:57 (12): 1786-1792
被引量:45
标识
DOI:10.1107/s0907444901014482
摘要
The crystal structure of a highly alkaline low molecular weight pectate lyase (Pel-15) was determined at 1.5 A resolution by the multiple isomorphous replacement (MIR) method. This is the first pectate lyase structure from polysaccharide lyase family 3. The overall structure is a simple eight-turn right-handed parallel beta-helix domain with one long loop protruding from one side of the beta-helix. The low molecular weight of Pel-15 derives from the lack of N- and C-terminal extensions that are found in many beta-helix proteins. Although the structure has one calcium ion at pH 6.7, raising the pH to 9.5 results in the binding of an additional calcium ion. The common calcium ion found in both the pH 6.5 and 9.5 structures seems to stabilize both the beta-helix structure and the long protruding loop. The additional calcium ion found in the pH 9.5 structure alone may neutralize the acidic substrate. The region around the additional calcium ion is thought to bind to the substrate, as this region is rich in charged amino-acid residues which are required in catalysis.
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