Atomic-resolution structures of horse liver alcohol dehydrogenase with NAD(+) and fluoroalcohols define strained Michaelis complexes.
Atomic-resolution structures of horse liver alcohol dehydrogenase with NAD(+) and fluoroalcohols define strained Michaelis complexes.
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DOI：
10.1021/bi300378n
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发表时间：
2012-05-15
期刊：
影响因子：
2.9
通讯作者：
Ramaswamy S
中科院分区：
文献类型：
--
作者：
Plapp BV;Ramaswamy S
马肝醇脱氢酶与NAD+和非反应性底物类似物2，2，2-三氟乙醇或2，3，4，5，6-五氟苄醇复合的结构在100 K下以1.12或1.14 μ m的分辨率测定，提供原子位置的估计，总误差约为0.02 μ m，配体结合的几何形状，氨基酸残基和沃茨的替代构象的描述，以及应变烟酰胺环的证据。来自两个同源二聚体结构的四个独立亚基在肽骨架构象上仅略有不同。在每个复合物中的748个残基中，确定了50个氨基酸侧链的替代构象，Leu-57和Leu-116适应不同的构象以适应活性位点处的不同醇。每个氟代醇占据一个位置，并且醇的氟被很好地分离。这些结构非常类似于预期的米氏络合物，其中醇的亚甲基碳的pro-R氢指向烟酰胺环的C4 N的表面，C到C的距离为3.40 nm。醇的氧以锌醇盐预期的距离（1.96 μ m）与催化锌连接，并在质子中继系统中与Ser-48的羟基形成低势垒氢键（2.52 μ m）。通过X射线精修（对键距和平面性无限制）测定，两种复合物中的烟酰胺环略微起皱（准船形构象，相对于其他原子的平面，C4 N的扭转角为5.9°，N1 N为4.8°），键距与NAD（P）+相比略有不同。看来烟酰胺环在醇氧化的路径上向过渡态应变。
Structures of horse liver alcohol dehydrogenase complexed with NAD+ and unreactive substrate analogues, 2,2,2-trifluoroethanol or 2,3,4,5,6-pentafluorobenzyl alcohol, were determined at 100 K at 1.12 or 1.14 Å resolution, providing estimates of atomic positions with overall errors of about 0.02 Å, geometry of ligand binding, descriptions of alternative conformations of amino acid residues and waters, and evidence of a strained nicotinamide ring. The four independent subunits from the two homodimeric structures differ only slightly in the peptide backbone conformation. Alternative conformations for amino acid side chains were identified for 50 of the 748 residues in each complex, and Leu-57 and Leu-116 adapt different conformations to accommodate the different alcohols at the active site. Each fluoroalcohol occupies one position, and the fluorines of the alcohols are well resolved. These structures closely resemble the expected Michaelis complexes with the pro-R hydrogens of the methylene carbons of the alcohols directed toward the re-face of C4N of the nicotinamide rings with a C to C distance of 3.40 Å. The oxygens of the alcohols are ligated to the catalytic zinc at a distance expected for a zinc alkoxide (1.96 Å) and participate in a low-barrier hydrogen bond (2.52 Å) with the hydroxyl group of Ser-48 in a proton relay system. As determined by X-ray refinement with no restraints on bond distances and planarity, the nicotinamide rings in the two complexes are slightly puckered (quasi-boat conformation, with torsion angles of 5.9° for C4N and 4.8° for N1N relative to the plane of the other atoms) and bond distances that are somewhat different as compared to those found for NAD(P)+. It appears that the nicotinamide ring is strained toward the transition state on the path to alcohol oxidation.
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影响因子：
15
作者：
ALMARSSON, O;BRUICE, TC
通讯作者：
BRUICE, TC
DOI：
10.1073/pnas.94.24.12797
发表时间：
1997-11-25
影响因子：
11.1
作者：
Bahnson, BJ;Colby, TD;Klinman, JP
通讯作者：
Klinman, JP
影响因子：
8
作者：
Eklund, H.;Ramaswamy, S.
通讯作者：
Ramaswamy, S.
影响因子：
15
作者：
Billeter, SR;Webb, SP;Hammes-Schiffer, S
通讯作者：
Hammes-Schiffer, S
影响因子：
--
作者：
BONDI, A
通讯作者：
BONDI, A