Structure of a eukaryotic cholinephosphotransferase-1 reveals mechanisms of substrate recognition and catalysis.
Structure of a eukaryotic cholinephosphotransferase-1 reveals mechanisms of substrate recognition and catalysis.
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DOI：
10.1038/s41467-023-38003-9
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发表时间：
2023-05-13
影响因子：
16.6
通讯作者：
Zhou, Ming
中科院分区：
文献类型：
--
作者：
Wang, Lie;Zhou, Ming
磷脂酰胆碱（PC）是真核细胞膜中最丰富的磷脂。在真核生物中，两种高度同源的酶胆碱磷酸转移酶-1（CHPT 1）和胆碱/乙醇胺磷酸转移酶-1（CEPT 1）催化PC从头合成的最后一步。CHPT 1/CEPT 1连接两种底物，胞苷二磷酸胆碱（CDP-胆碱）和二酰基甘油（DAG），以产生PC，并且Mg 2+是反应所需的。然而，底物识别和催化的机制仍然没有得到解决。在这里，我们报告的结构CHPT 1从非洲爪蟾（xlCHPT 1）确定的冷冻电子显微镜的整体分辨率为~3.2 μ m。xlCHPT 1形成同源二聚体，并且每个原聚体具有10个跨膜螺旋（TM）。前6个TM在膜中切割出一个锥形外壳，催化作用在其中发生。外壳向胞质侧打开，其中CDP-胆碱和两个Mg 2+被协调。这些结构鉴定了真核CHPT 1/CEPT 1特有的催化位点，并提出了DAG的入口途径。这些结构还揭示了TM 3 -6和TM 7 -10之间的内部假双重对称性，并表明CHPT 1/CEPT 1可能通过基因复制从其遥远的原核祖先进化而来。CDP-醇磷脂酰转移酶（CDP-AP）是合成磷脂的膜包埋酶家族。作者报道了真核CDP-AP的结构和功能研究，揭示了与原核同源物不同的催化中心和结构折叠。
Phosphatidylcholine (PC) is the most abundant phospholipid in eukaryotic cell membranes. In eukaryotes, two highly homologous enzymes, cholinephosphotransferase-1 (CHPT1) and choline/ethanolamine phosphotransferase-1 (CEPT1) catalyze the final step of de novo PC synthesis. CHPT1/CEPT1 joins two substrates, cytidine diphosphate-choline (CDP-choline) and diacylglycerol (DAG), to produce PC, and Mg2+ is required for the reaction. However, mechanisms of substrate recognition and catalysis remain unresolved. Here we report structures of a CHPT1 from Xenopus laevis (xlCHPT1) determined by cryo-electron microscopy to an overall resolution of ~3.2 Å. xlCHPT1 forms a homodimer, and each protomer has 10 transmembrane helices (TMs). The first 6 TMs carve out a cone-shaped enclosure in the membrane in which the catalysis occurs. The enclosure opens to the cytosolic side, where a CDP-choline and two Mg2+ are coordinated. The structures identify a catalytic site unique to eukaryotic CHPT1/CEPT1 and suggest an entryway for DAG. The structures also reveal an internal pseudo two-fold symmetry between TM3-6 and TM7-10, and suggest that CHPT1/CEPT1 may have evolved from their distant prokaryotic ancestors through gene duplication. CDP-alcohol phosphatidyltransferase (CDP-AP) is a family of membrane-embedded enzymes that synthesize phospholipids. The authors report structural and functional studies of a eukaryotic CDP-AP and reveal a catalytic center and structural fold different from these of prokaryotic homologs.
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影响因子：
48
作者：
Kucukelbir, Alp;Sigworth, Fred J.;Tagare, Hemant D.
通讯作者：
Tagare, Hemant D.
DOI：
10.1126/science.aao6326
发表时间：
2018-01-12
期刊：
Science (New York, N.Y.)
影响因子：
--
作者：
Rana MS;Kumar P;Lee CJ;Verardi R;Rajashankar KR;Banerjee A
通讯作者：
Banerjee A
影响因子：
48
作者：
Barad BA;Echols N;Wang RY;Cheng Y;DiMaio F;Adams PD;Fraser JS
通讯作者：
Fraser JS
影响因子：
64.8
作者：
Jumper J;Evans R;Pritzel A;Green T;Figurnov M;Ronneberger O;Tunyasuvunakool K;Bates R;Žídek A;Potapenko A;Bridgland A;Meyer C;Kohl SAA;Ballard AJ;Cowie A;Romera-Paredes B;Nikolov S;Jain R;Adler J;Back T;Petersen S;Reiman D;Clancy E;Zielinski M;Steinegger M;Pacholska M;Berghammer T;Bodenstein S;Silver D;Vinyals O;Senior AW;Kavukcuoglu K;Kohli P;Hassabis D
通讯作者：
Hassabis D
电子计数和束诱导运动校正可实现近原子分辨率的单粒子冷冻电镜。
影响因子：
48
作者：
Li, Xueming;Mooney, Paul;Zheng, Shawn;Booth, Christopher R.;Braunfeld, Michael B.;Gubbens, Sander;Agard, David A.;Cheng, Yifan
通讯作者：
Cheng, Yifan