Structural characterization of the apo form and NADH binary complex of human lactate dehydrogenase.
Structural characterization of the apo form and NADH binary complex of human lactate dehydrogenase.
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Apo形式的结构表征和人乳酸脱氢酶的NADH二元复合物。
DOI：
10.1107/s1399004714005422
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发表时间：
2014-05
期刊：
影响因子：
--
通讯作者：
Dreveny I
中科院分区：
文献类型：
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作者：
Dempster S;Harper S;Moses JE;Dreveny I
报道了一种适于配基浸泡的人乳酸脱氢酶AAPO形式的晶体结构和NADH二元络合物结构。乳酸脱氢酶A(LDH-A)是无氧呼吸的关键酶，主要存在于骨骼肌中，催化丙酮酸在NADH存在下可逆地转化为乳酸。LDH-A在许多肿瘤中过表达，因此成为抗癌药物开发的一个有吸引力的靶点。人LDH-A在抑制剂存在下的晶体结构已被描述，但目前还没有任何哺乳动物LDH-A的apo或二进制NADH结合形式的结构。在这里，在P4122空间群中，以2.1 ä的分辨率解算了人LDH-A的载脂蛋白结构。活性中心环采用开放构象，堆积和结晶条件表明该晶型适合于浸泡实验。用辅因子NADH评估了浸泡势，在没有任何抑制剂的情况下，它产生了配体结合的晶体结构。结构表明，NADH结合引起活性部位环和相邻螺旋的微小构象变化。与其他真核细胞载脂蛋白LDH结构的比较表明，环内相互作用是保守的。这些结构为辅因子结合提供了新的见解，并为片段和抑制剂的浸泡实验提供了基础。
A crystal structure of the human lactate dehydrogenase A apo form suitable for ligand soaking and a NADH binary-complex structure are presented. Lactate dehydrogenase A (LDH-A) is a key enzyme in anaerobic respiration that is predominantly found in skeletal muscle and catalyses the reversible conversion of pyruvate to lactate in the presence of NADH. LDH-A is overexpressed in many tumours and has therefore emerged as an attractive target for anticancer drug discovery. Crystal structures of human LDH-A in the presence of inhibitors have been described, but currently no structures of the apo or binary NADH-bound forms are available for any mammalian LDH-A. Here, the apo structure of human LDH-A was solved at a resolution of 2.1 Å in space group P4122. The active-site loop adopts an open conformation and the packing and crystallization conditions suggest that the crystal form is suitable for soaking experiments. The soaking potential was assessed with the cofactor NADH, which yielded a ligand-bound crystal structure in the absence of any inhibitors. The structures show that NADH binding induces small conformational changes in the active-site loop and an adjacent helix. A comparison with other eukaryotic apo LDH structures reveals the conservation of intra-loop interactions. The structures provide novel insight into cofactor binding and provide the foundation for soaking experiments with fragments and inhibitors.