ATP-citrate lyase (ACLY) synthesizes cytosolic acetyl coenzyme A (acetyl-CoA), a fundamental cellular building block. Accordingly, aberrant ACLY activity is observed in many diseases. Here we report cryo-EM structures of human ACLY, alone or bound to substrates or products. ACLY forms a homotetramer with a rigid citrate synthase homology (CSH) module, flanked by four flexible acetyl-CoA synthetase homology (ASH) domains; CoA is bound at the CSH-ASH interface in mutually exclusive productive or unproductive conformations. The structure of a catalytic mutant of ACLY in the presence of ATP, citrate and CoA substrates reveals a phospho-citryl-CoA intermediate in the ASH domain. ACLY with acetyl-CoA and oxaloacetate products shows the products bound in the ASH domain, with an additional oxaloacetate in the CSH domain, which could function in ACLY autoinhibition. These structures, which are supported by biochemical and biophysical data, challenge previous proposals of the ACLY catalytic mechanism and suggest additional therapeutic possibilities for ACLY-associated metabolic disorders.

中文翻译：

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ATP-柠檬酸裂解酶产生乙酰辅酶A的分子基础。

ATP-柠檬酸裂解酶 (ACLY) 合成细胞溶质乙酰辅酶 A (乙酰辅酶 A)，这是一种基本的细胞结构单元。因此，在许多疾病中观察到异常的 ACLY 活性。在这里，我们报告了人类 ACLY 的冷冻电镜结构，单独或与底物或产品结合。ACLY 形成具有刚性柠檬酸合酶同源 (CSH) 模块的同源四聚体，两侧是四个灵活的乙酰辅酶 A 合成酶同源 (ASH) 结构域；CoA 以互斥的生产或非生产构象结合在 CSH-ASH 界面上。在存在 ATP、柠檬酸盐和 CoA 底物的情况下，ACLY 催化突变体的结构揭示了 ASH 结构域中的磷酸-柠檬酰-CoA 中间体。ACLY 与乙酰辅酶 A 和草酰乙酸产物结合显示在 ASH 域中结合的产物，在 CSH 域中具有额外的草酰乙酸，它可以在 ACLY 自身抑制中起作用。这些结构得到了生化和生物物理数据的支持，挑战了先前关于 ACLY 催化机制的提议，并为 ACLY 相关的代谢紊乱提供了额外的治疗可能性。