The crystal structure of D-lactate dehydrogenase, a peripheral membrane respiratory enzyme
The crystal structure of D-lactate dehydrogenase, a peripheral membrane respiratory enzyme
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DOI：
10.1073/pnas.97.17.9413
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发表时间：
2000-08-15
影响因子：
11.1
通讯作者：
Eisenberg, D
中科院分区：
文献类型：
--
作者：
Dym, O;Pratt, EA;Eisenberg, D
大肠杆菌的D-乳酸脱氢酶（D-LDH）是一种参与电子传递的外周膜呼吸酶，位于内膜的细胞质侧。 D-LDH 催化 D-乳酸氧化为丙酮酸，并与氨基酸和糖的跨膜转运结合。在这里，我们以 1.9 埃分辨率描述了 D-LDH 三个结构域的晶体结构：黄素腺嘌呤二核苷酸 (FAD) 结合结构域、帽结构域和膜结合结构域。 FAD 结合结构域包含非共价结合的 FAD 辅因子还原 D-乳酸的位点，并且具有与最近发现的包含 FAD 的蛋白质家族的其他成员相似的整体折叠。这种结构相似性也延伸到了帽结构域。 D-LDH 与 FAD 家族其他成员之间最显着的区别是膜结合结构域，该结构域在某些蛋白质中要么不存在，要么存在显着差异。 D-LDH 膜结合结构域呈现出带有 6 个 Arg 和 5 个 Lys 残基的正电表面，可能与膜带负电荷的磷脂头基相互作用。因此，D-LDH 似乎通过静电力而不是疏水力结合膜。
D-Lactate dehydrogenase (D-LDH) of Escherichia coli is a peripheral membrane respiratory enzyme involved in electron transfer, located on the cytoplasmic side of the inner membrane. D-LDH catalyzes the oxidation of D-lactate to pyruvate, which is coupled to transmembrane transport of amino acids and sugars. Here we describe the crystal structure at 1.9 Angstrom resolution of the three domains of D-LDH: the flavin adenine dinucleotide (FAD)-binding domain, the cap domain, and the membrane-binding domain. The FAD-binding domain contains the site of D-lactate reduction by a noncovalently bound FAD cofactor and has an overall fold similar to other members of a recently discovered FAD-containing family of proteins. This structural similarity extends to the cap domain as well. The most prominent difference between D-LDH and the other members of the FAD-containing family is the membrane-binding domain, which is either absent in some of these proteins or differs significantly. The D-LDH membrane-binding domain presents an electropositive surface with six Arg and five Lys residues, which presumably interacts with the negatively charged phospholipid head groups of the membrane. Thus, D-LDH appears to bind the membrane through electrostatic rather than hydrophobic forces.