Ternary structure reveals mechanism of a membrane diacylglycerol kinase.
Ternary structure reveals mechanism of a membrane diacylglycerol kinase.
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DOI：
10.1038/ncomms10140
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发表时间：
2015-12-17
影响因子：
16.6
通讯作者：
Caffrey M
中科院分区：
文献类型：
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作者：
Li D;Stansfeld PJ;Sansom MSP;Keogh A;Vogeley L;Howe N;Lyons JA;Aragao D;Fromme P;Fromme R;Basu S;Grotjohann I;Kupitz C;Rendek K;Weierstall U;Zatsepin NA;Cherezov V;Liu W;Bandaru S;English NJ;Gati C;Barty A;Yefanov O;Chapman HN;Diederichs K;Messerschmidt M;Boutet S;Williams GJ;Marvin Seibert M;Caffrey M
二酰甘油激酶催化大肠杆菌质膜中二酰甘油向磷脂酸的ATP依赖性转化。这个完整的膜三聚体，每个亚基有121个残基的小尺寸，意味着可用的蛋白质必须经济地用于工艺三个催化和底物结合位点集中在膜/胞质溶胶界面。大自然是如何完成这一非凡的壮举，揭示了在这里作为一个三元复合物与结合脂质底物和ATP类似物捕获的激酶的晶体结构。通过诱变鉴定为活性所必需的残基装饰活性位点并通过三元结构合理化。ATP类似物的γ-磷酸被定位为直接转移到脂质的伯羟基，其酰基链在膜中。提出了这种独特的酶的催化机制。活性位点的结构显示出明显的证据，表明它是由趋同进化产生的。 甘油二酯激酶是一种小的细菌膜结合三聚体，催化甘油二酯转化为磷脂酸。在这里，作者解决了与脂质底物和ATP类似物结合的激酶的晶体结构，并表明活性位点是通过趋同进化产生的。
Diacylglycerol kinase catalyses the ATP-dependent conversion of diacylglycerol to phosphatidic acid in the plasma membrane of Escherichia coli. The small size of this integral membrane trimer, which has 121 residues per subunit, means that available protein must be used economically to craft three catalytic and substrate-binding sites centred about the membrane/cytosol interface. How nature has accomplished this extraordinary feat is revealed here in a crystal structure of the kinase captured as a ternary complex with bound lipid substrate and an ATP analogue. Residues, identified as essential for activity by mutagenesis, decorate the active site and are rationalized by the ternary structure. The γ-phosphate of the ATP analogue is positioned for direct transfer to the primary hydroxyl of the lipid whose acyl chain is in the membrane. A catalytic mechanism for this unique enzyme is proposed. The active site architecture shows clear evidence of having arisen by convergent evolution. Diacylglycerol kinase is a small bacterial membrane-bound trimer that catalyses diacylglycerol conversion to phosphatidic acid. Here, the authors solve the crystal structure of the kinase bound to a lipid substrate and an ATP analogue, and show that the active site arose through convergent evolution.