Prigge S T, Boyington J C, Gaffney B J, Amzel L M
Department of Biophysics and Biophysical Chemistry, Johns Hopkins University, Baltimore, Maryland, USA.
Proteins. 1996 Mar;24(3):275-91. doi: 10.1002/(SICI)1097-0134(199603)24:3<275::AID-PROT1>3.0.CO;2-G.
Lipoxygenases are a class of non-heme iron dioxygenases which catalyze the hydroperoxidation of fatty acids for the biosynthesis of leukotrienes and lipoxins. The structure of the 839-residue soybean lipoxygenase-1 was used as a template to model human 5-, 12-, and 15-lipoxygenases. A distance-based algorithm for placing side chains in a low homology environment (only the four iron ligands were fixed during side chain placement) was devised. Twenty-six of the 56 conserved lipoxygenase residues were grouped in four distinct regions of the enzyme. These regions were analyzed to discern whether the side chain interactions could be duplicated in the models or whether alternate conformers should be considered. The effects of site directed mutagenesis variants were rationalized using the models of the human lipoxygenases. In particular, variants which shifted positional specificity between 12- and 15-lipoxygenase activity were analyzed. Analysis of active site residues produced a model which accounts for observed lipoxygenase positional specificity and stereospecificity.
脂氧合酶是一类非血红素铁双加氧酶，可催化脂肪酸的氢过氧化反应，用于白三烯和脂氧素的生物合成。以839个残基的大豆脂氧合酶-1的结构为模板，对人5-、12-和15-脂氧合酶进行建模。设计了一种基于距离的算法，用于在低同源性环境中放置侧链（在侧链放置过程中仅固定四个铁配体）。56个保守的脂氧合酶残基中的26个被分组在酶的四个不同区域。对这些区域进行分析，以确定侧链相互作用是否可以在模型中重复，或者是否应考虑其他构象异构体。使用人脂氧合酶模型对定点诱变变体的作用进行了合理化解释。特别地，分析了在12-和15-脂氧合酶活性之间改变位置特异性的变体。对活性位点残基的分析产生了一个模型，该模型解释了观察到的脂氧合酶位置特异性和立体特异性。
