Aldehyde dehydrogenase - Maintaining critical active site geometry at motif 8 in the class 3 enzyme
Aldehyde dehydrogenase - Maintaining critical active site geometry at motif 8 in the class 3 enzyme
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DOI：
10.1046/j.1432-1327.2001.01926.x
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发表时间：
2001-02-01
期刊：
影响因子：
--
通讯作者：
Nicholas, H
中科院分区：
文献类型：
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作者：
Hempel, J;Kuo, I;Nicholas, H
所有已知的，不同的成员的醛脱氢酶（ALDH）大家庭的比对发现只有两个严格保守的，非甘氨酸残基，谷氨酸和苯丙氨酸残基。两者都发生在一个高度保守的“基序”片段中，并且都占据了催化漏斗底部三级结构中的战略位置。在3类ALDH中，这些是Glu 333和Phe 335。此外，Asp 247不是高度保守的，但却是3类ALDH的特征，它使Glu 333和Phe 335之间的主链氢键化。这三个残基保守突变。确定的两个NAD/丙醛和NADP/苯甲醛底物对的米氏常数显示所有三个残基是至关重要的有效催化，并建议，氢键Asp 247是一个关键要素，在保持精确的几何形状的关键要素在活性位点。
Alignment of all known, diverse members of the aldehyde dehydrogenase (ALDH) extended family revealed only two strictly conserved, nonglycine residues, a glutamate and a phenylalanine residue. Both occur in one of the highly conserved 'motif' segments and both occupy strategic locations in the tertiary structure at the bottom of the catalytic funnel. In class 3 ALDH, these are Glu333 and Phe335. In addition, Asp247, which is not highly conserved but is characteristic of class 3 ALDHs, hydrogen bonds the main chain between Glu333 and Phe335. These three residues were mutated conservatively. Michaelis constants determined for both NAD/propanal and NADP/benzaldehyde substrate pairs show all three residues to be crucial to effective catalysis, and suggest that the hydrogen bond to Asp247 is a key element in maintaining precise geometry of key elements at the active site.