Spectroscopic characterization of soybean lipoxygenase-1 mutants: the role of second coordination sphere residues in the regulation of enzyme activity.
Spectroscopic characterization of soybean lipoxygenase-1 mutants: the role of second coordination sphere residues in the regulation of enzyme activity.
复制标题
大豆脂氧合酶-1突变体的光谱表征：第二配位球残基在酶活性调节中的作用。
DOI：
10.1021/bi027380g
复制
发表时间：
2003
期刊：
影响因子：
2.9
通讯作者：
Solomon,EdwardI
中科院分区：
文献类型：
--
作者：
Schenk,Gerhard;Neidig,MichaelL;Zhou,Jing;Holman,TheodoreR;Solomon,EdwardI
Lipoxygenases are non-heme iron enzymes, which catalyze the stereo- and regiospecific hydroperoxidation of unsaturated fatty acids. Spectroscopic studies on soybean lipoxygenase have shown that the ferrous form of the enzyme is a mixture of five- and six-coordinate species (40 and 60%, respectively). Addition of substrate leads to a purely six-coordinate form. A series of mutations in the second coordination sphere (Q697E, Q697N, Q495A, and Q495E) were generated, and the structures of the mutants were solved by crystallography [Tomchick et al. (2001)Biochemistry 40, 7509−7517]. While this study clearly showed the contribution of H-bond interactions between the first and the second coordination spheres in catalysis, no correlation with the coordination environment of the FeIIwas observed. A recent study using density-functional theory [Lehnert and Solomon (2002)J. Biol. Inorg. Chem. 8, 294−305] indicated that coordination flexibility, involving the Asn694 ligand, is regulated via H-bond interactions. In this paper, we investigate the solution structures of the second coordination sphere mutants using CD and MCD spectroscopy since these techniques are more sensitive indicators of the first coordination sphere ligation of FeIIsystems. Our data demonstrate that the iron coordination environment directly relates to activity, with the mutations that have the ability to form a five-coordinate/six-coordinate mixture being more active. We propose that the H-bond between the weak Asn694 ligand and the Gln697 plays a key role in the modulation of the coordination flexibility of Asn694, and thus, is crucial for the regulation of enzyme reactivity.
大豆脂氧合酶L3的结构及其与L1同工酶的比较
DOI：
--
发表时间：
1997
期刊：
Proteins: Structure, Function, and Bioinformatics
影响因子：
--
作者：
E. Skrzypczak‐Jankun;L. Amzel;B. A. Kroa;M. Funk
通讯作者：
M. Funk
DOI：
10.1111/j.1432-1033.1977.tb11617.x
发表时间：
1977
期刊：
European journal of biochemistry
影响因子：
--
作者：
M. Egmond;P. Fasella;G. Veldink;J. Vliegenthart;J. Boldingh
通讯作者：
J. Boldingh