Development of diacyltetrol lipids as activators for the C1 domain of protein kinase C
作者:Narsimha Mamidi、Sukhamoy Gorai、Rakesh Mukherjee、Debasis Manna
DOI:10.1039/c2mb05452c
日期:——
The protein kinase C (PKC) family of serine/threonine kinases is an attractive drug target for the treatment of cancer and other diseases. Diacylglycerol (DAG), phorbol esters and others act as ligands for the C1 domain of PKC isoforms. Inspection of the crystal structure of the PKCδ C1b subdomain in complex with phorbol-13-O-acetate shows that one carbonyl group and two hydroxyl groups play pivotal roles in recognition of the C1 domain. To understand the importance of two hydroxyl groups of phorbol esters in PKC binding and to develop effective PKC activators, we synthesized DAG like diacyltetrols (DATs) and studied binding affinities with C1b subdomains of PKCδ and PKCθ. DATs, with the stereochemistry of natural DAGs at the sn-2 position, were synthesized from (+)-diethyl L-tartrate in four to seven steps as single isomers. The calculated EC50 values for the short and long chain DATs varied in the range of 3–6 μM. Furthermore, the fluorescence anisotropy values of the proteins were increased in the presence of DATs in a similar manner to that of DAGs. Molecular docking of DATs (1b–4b) with PKCδ C1b showed that the DATs form hydrogen bonds with the polar residues and backbone of the protein, at the same binding site, as that of DAG and phorbol esters. Our findings reveal that DATs represent an attractive group of C1 domain ligands that can be used as research tools or further structurally modified for potential drug development.
蛋白激酶C (PKC) 家族的丝氨酸/苏氨酸激酶是治疗癌症和其他疾病的一个有吸引力的药物靶点。二酰基甘油 (DAG)、佛尔波酯等作为PKC异构体C1结构域的配体。检查PKCδ C1b亚结构域与佛尔波-13-O-醋酸酯的复合物的晶体结构显示,一个羰基和两个羟基在C1结构域的识别中起着关键作用。为了了解佛尔波酯的两个羟基在PKC结合中的重要性,并开发有效的PKC激动剂,我们合成了类似DAG的二酰基醇 (DATs),并研究了它们与PKCδ和PKCθ的C1b亚结构域的结合亲和力。具有天然DAG在sn-2位立体化学的DAT,采用(+)-二乙基L-酒石酸酯在四到七个步骤中合成为单一异构体。短链和长链DAT的计算EC50值在3–6 μM范围内变化。此外,在DAT存在的情况下,蛋白质的荧光各向异性值也以类似DAG的方式增加。DAT(1b-4b)与PKCδ C1b的分子对接显示,DAT与极性残基和蛋白质的主链形成氢键,位于与DAG和佛尔波酯相同的结合位点。我们的发现表明,DAT代表一组有吸引力的C1结构域配体,可以作为研究工具或进一步进行结构修饰以开发潜在药物。