Distinct structural mechanisms for inhibition of pyruvate dehydrogenase kinase isoforms by AZD7545, dichloroacetate, and radicicol
Distinct structural mechanisms for inhibition of pyruvate dehydrogenase kinase isoforms by AZD7545, dichloroacetate, and radicicol
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DOI：
10.1016/j.str.2007.07.001
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发表时间：
2007-08-01
期刊：
影响因子：
5.7
通讯作者：
Chuang, David T.
中科院分区：
文献类型：
--
作者：
Kato, Masato;Li, Jun;Chuang, David T.
丙酮酸脱氢酶激酶（PDK）是线粒体中通过可逆磷酸化调节丙酮酸脱氢酶复合物（PDC）的分子开关。我们已经确定了与抑制剂AZD 7545，二氯乙酸（DCA）和根赤霉素结合的人PDK 1或PDK 3的结构。我们发现AZD 7545的三氟甲基丙酰胺末端投射到PDK 1的硫辛酰结合口袋中。这种相互作用通过中止激酶与PDC支架的结合而导致PDK 1和PDK 3活性的抑制。有趣的是，饱和浓度的AZD 7545强烈地增加了无支架的PDK 3活性，类似于内部硫辛酰结构域。良好的DCA密度存在于PDK 1的N-末端结构域的螺旋束中。结合DCA促进局部构象变化，这些变化被传递到PDK 1的核苷酸结合口袋和硫辛酰结合口袋，导致激酶活性失活。最后，根赤霉素通过直接结合PDK 3的ATP结合口袋来抑制激酶活性，类似于来自相同ATP酶/激酶超家族的Hsp 90和Topo A。
Pyruvate dehydrogenase kinase (PDK) isoforms are molecular switches that clownregulate the pyruvate dehydrogenase complex (PDC) by reversible phosphorylation in mitochondria. We have determined structures of human PDK1 or PDK3 bound to the inhibitors AZD7545, dichloroacetate (DCA), and radicicol. We show that the trifluoromethylpropanamide end of AZD7545 projects into the lipoyl-binding pocket of PDK1. This interaction results in inhibition of PDK1 and PDK3 activities by aborting kinase binding to the PDC scaffold. Paradoxically, AZD7545 at saturating concentrations robustly increases scaffold-free PDK3 activity, similar to the inner lipoyl domain. Good DCA density is present in the helix bundle in the N-terminal domain of PDK1. Bound DCA promotes local conformational changes that are communicated to both nucleotide-binding and lipoyl-binding pockets of PDK1, leading to the inactivation of kinase activity. Finally, radicicol inhibits kinase activity by binding directly to the ATP-binding pocket of PDK3, similar to Hsp90 and Topo A from the same ATPase/ kinase superfamily.