STRUCTURES OF 3 HUMAN BETA-ALCOHOL-DEHYDROGENASE VARIANTS - CORRELATIONS WITH THEIR FUNCTIONAL DIFFERENCES
STRUCTURES OF 3 HUMAN BETA-ALCOHOL-DEHYDROGENASE VARIANTS - CORRELATIONS WITH THEIR FUNCTIONAL DIFFERENCES
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DOI：
10.1006/jmbi.1994.1382
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发表时间：
1994-06-10
影响因子：
5.6
通讯作者：
AMZEL, LM
中科院分区：
文献类型：
--
作者：
HURLEY, TD;BOSRON, WF;AMZEL, LM
测定了人β-乙醇脱氢酶三种变体的三维结构，其分辨率为2.5 μ m。这三种结构的不同之处仅在于47位的氨基酸和占据醇结合位点的分子。人β 1醇脱氢酶在47位有一个Arg，与NAD（H）和环己醇形成复合物。在大约50%的亚洲人群中发现的β 1醇脱氢酶的一种天然变体在47位具有一个His（β 2或β 47 H），并与NAD+和抑制剂4-碘吡唑形成复合物。以甘氨酸取代精氨酸47（β 47 G）的β 1-乙醇脱氢酶定点突变体与NAD+形成复合物。通过比较这些结构的共同和独特特征，很明显，位置47对蛋白质-辅酶相互作用的强度有显著贡献。用His取代Arg 47产生的酶对辅酶的亲和力降低了100倍，但酶结构没有发生更大的变化。Arg 47被Gly取代产生的酶具有与野生型酶相比更类似于在位置47处具有His的酶的辅酶结合特征，但是Gly 47变体的结构在辅酶结合位点中和周围表现出差异。这些变化包括催化结构域向辅酶结构域的约0.8 °的刚体旋转和氨基酸侧链的局部重排，例如Lys 228相对于β 1酶的1.0 °移动。这些结构改变可以补偿由Arg 47贡献的辅酶相互作用的损失，并且可以解释Gly 47变体对辅酶的高亲和力。
The three-dimensional structures of three variants of human β alcohol dehydrogenase have been determined to 2·5 Å resolution. These three structures differ only in the amino acid at position 47 and the molecules occupying the alcohol binding site. Human β1alcohol dehydrogenase has an Arg at position 47 and was crystallized in a complex with NAD(H) and cyclohexanol. A naturally occurring variant of β1alcohol dehydrogenase, found in approximately 50% of the Asian population, possesses a His at position 47 (β2or β47H) and was crystallized in a complex with NAD+and the inhibitor 4-iodopyrazole. A site-directed mutant of β1alcohol dehydrogenase in which a Gly is substituted for Arg47 (β47G) was crystallized in a complex with NAD+. By comparing both the common and unique features of these structures, it is clear that position 47 contributes significantly to the strength of protein-coenzyme interactions. The substitution of Arg47 by His produces an enzyme with a 100-fold lower affinity for coenzyme, but creates no larger changes in the enzyme structure. The substitution of Arg47 by Gly produces an enzyme with coenzyme binding characteristics more similar to the wild-type enzyme than to the enzyme with His at position 47, but the structure of the Gly47 variant exhibits differences in and around the coenzyme binding site. These changes involve a rigid-body rotation of the catalytic domain towards the coenzyme domain by approximately 0·8° and local rearrangements of amino acid side-chains, such as a 1·0 Å movement of Lys228, relative to the β1enzyme. These structural alterations may compensate for the loss of coenzyme interactions contributed by Arg47 and can explain the high affinity of the Gly47 variant for coenzyme.