Balanol analogues probe specificity determinants and the conformational malleability of the cyclic 3′,5′-adenosine monophosphate-dependent protein kinase catalytic subunit
Balanol analogues probe specificity determinants and the conformational malleability of the cyclic 3′,5′-adenosine monophosphate-dependent protein kinase catalytic subunit
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DOI：
10.1021/bi035042p
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发表时间：
2004-01-13
期刊：
影响因子：
2.9
通讯作者：
Taylor, SS
中科院分区：
文献类型：
--
作者：
Akamine, P;Madhusudan;Taylor, SS
蛋白激酶家族是治疗剂的主要靶标，因为不受调节的蛋白激酶活性与无数疾病相关。Balanol是一种由四个环组成的真菌代谢物，有效地抑制Ser/Thr蛋白激酶，并且可以被修饰以产生作为所需药物化合物的选择性特征的有效抑制剂。在这里，我们描述了三个balanol类似物，抑制环3 '，5'-腺苷一磷酸依赖性蛋白激酶（PKA）比钙和磷脂依赖性蛋白激酶（PKC）更具体和有效。热稳定性和抑制效力的相关性表明，更好的抑制剂赋予增强的热变性保护。与每个类似物复合的PKA催化（C）亚基的晶体结构显示富含Gly的环稳定在“中间”构象，与重要的磷酰基转移残基脱离。干扰PKA C-末端尾部的类似物具有稍弱的抑制效力。PKA C亚基的延展性通过活性位点残基说明，所述活性位点残基根据结合的配体采用交替旋转异构体。基于与PKA的序列同源性，本文描述了PKC活性位点的初步模型。Balanol类似物用于测试模型，并突出PKA和PKC的活性位点局部环境的差异。PKA C亚基似乎耐受具有D-环修饰的balanol类似物; PKC不耐受。我们将这种偏好差异归因于可变的B螺旋和C末端尾部。通过了解配体结合的细节，可以设计更特异和有效的抑制剂，以区分密切相关的AGC蛋白激酶家族成员。
The protein kinase family is a prime target for therapeutic agents, since unregulated protein kinase activities are linked to myriad diseases. Balanol, a fungal metabolite consisting of four rings, potently inhibits Ser/Thr protein kinases and can be modified to yield potent inhibitors that are selective-characteristics of a desirable pharmaceutical compound. Here, we characterize three balanol analogues that inhibit cyclic 3',5'-adenosine monophosphate-dependent protein kinase (PKA) more specifically and potently than calcium- and phospholipid-dependent protein kinase (PKC). Correlation of thermostability and inhibition potency suggests that better inhibitors confer enhanced protection against thermal denaturation. Crystal structures of the PKA catalytic (C) subunit complexed to each analogue show the Gly-rich loop stabilized in an "intermediate" conformation, disengaged from important phosphoryl transfer residues. An analogue that perturbs the PKA C-terminal tail has slightly weaker inhibition potency. The malleability of the PKA C subunit is illustrated by active site residues that adopt alternate rotamers depending on the ligand bound. On the basis of sequence homology to PKA, a preliminary model of the PKC active site is described. The balanol analogues serve to test the model and to highlight differences in the active site local environment of PKA and PKC. The PKA C subunit appears to tolerate balanol analogues with D-ring modifications; PKC does not. We attribute this difference in preference to the variable B helix and C-terminal tail. By understanding the details of ligand binding, more specific and potent inhibitors may be designed that differentiate among closely related AGC protein kinase family members.