Mechanistic insight into allosteric activation of human pyruvate carboxylase by acetyl-CoA.
Mechanistic insight into allosteric activation of human pyruvate carboxylase by acetyl-CoA.
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DOI：
10.1016/j.molcel.2022.09.033
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发表时间：
2022-10
期刊：
影响因子：
16
通讯作者：
P. Chai;P. Lan;Shaobai Li;D. Yao;Chenchen Chang;Mi Cao;Ya-feng Shen;S. Ge;Jian Wu;M. Lei;Xianqun Fan
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文献类型：
--
作者：
P. Chai;P. Lan;Shaobai Li;D. Yao;Chenchen Chang;Mi Cao;Ya-feng Shen;S. Ge;Jian Wu;M. Lei;Xianqun Fan
丙酮酸羧化酶(PC)催化丙酮酸的两步羧化反应生成草酰乙酸酯，在维持细胞代谢动态平衡中起着关键作用。由于与多种疾病有关，PC被认为是治疗肥胖症、糖尿病和癌症的潜在靶点。尽管60多年来，乙酰辅酶A一直被认为是PC的变构调节剂，但乙酰辅酶A如何诱导PC激活的潜在机制仍然是个谜。在这里，我们利用时间分辨低温电子显微镜，捕捉到了PC在催化循环过程中过渡态的快照。这些结构和生化研究表明，乙酰辅酶A使PC稳定在催化活性构象中，从而触发了一系列事件，包括ATP水解和两个反应中心之间的长距离通讯。这些发现为PC催化提供了一幅完整的图景，并揭示了乙酰辅酶A在所有生命王国中的必要生化反应中独特的变构机制。
Pyruvate carboxylase (PC) catalyzes the two-step carboxylation of pyruvate to produce oxaloacetate, playing a key role in the maintenance of metabolic homeostasis in cells. Given its involvement in multiple diseases, PC has been regarded as a potential therapeutic target for obesity, diabetes, and cancer. Albeit acetyl-CoA has been recognized as the allosteric regulator of PC for over 60 years, the underlying mechanism of how acetyl-CoA induces PC activation remains enigmatic. Herein, by using time-resolved cryo-electron microscopy, we have captured the snapshots of PC transitional states during its catalytic cycle. These structures and the biochemical studies reveal that acetyl-CoA stabilizes PC in a catalytically competent conformation, which triggers a cascade of events, including ATP hydrolysis and the long-distance communication between the two reactive centers. These findings provide an integrated picture for PC catalysis and unveil the unique allosteric mechanism of acetyl-CoA in an essential biochemical reaction in all kingdoms of life.