De Moliner Erika, Brown Nick R, Johnson Louise N
Laboratory of Molecular Biophysics, Department of Biochemistry, University of Oxford, UK.
Eur J Biochem. 2003 Aug;270(15):3174-81. doi: 10.1046/j.1432-1033.2003.03697.x.
Protein kinases are targets for therapeutic agents designed to intervene in signaling processes in the diseased state. Most kinase inhibitors are directed towards the conserved ATP binding site. Because the essential features of this site are conserved in all eukaryotic protein kinases, it is generally assumed that the same compound will bind in a similar manner to different protein kinases. The inhibitor 4,5,6,7-tetrabromobenzotriazole (TBB) is a selective inhibitor for the protein kinase CK2 (IC50 1.6 micro m) (Sarno et al. (2001) FEBS Letts.496, 44-48). Three other kinases [cyclin-dependent protein kinase 2 (CDK2), phosphorylase kinase and glycogen synthase kinase 3beta] exhibit approximately 10-fold weaker affinity for TBB than CK2. We report the crystal structure of TBB in complex with phospho-CDK2-cyclin A at 2.2 A resolution and compare the interactions with those observed for TBB bound to CK2. TBB binds at the ATP binding site of both kinases. In CDK2, each of the four bromine atoms makes polar contacts either to main chain oxygens in the hinge region of the kinase or to water molecules, in addition to several van der Waals contacts. The mode of binding of TBB to CDK2 is different from that to CK2. TBB in CDK2 is displaced more towards the hinge region between the N- and C-terminal lobes and rotated relative to TBB in CK2. The ATP binding pocket is wider in CDK2 than in CK2 resulting in fewer van der Waals contacts but TBB in CK2 does not contact the hinge. The structures show that, despite the conservation of the ATP binding pocket, the inhibitor is able to exploit different recognition features so that the same compound can bind in different ways to the two different kinases.
蛋白激酶是用于设计干预疾病状态下信号传导过程的治疗药物的靶点。大多数激酶抑制剂都作用于保守的ATP结合位点。由于该位点的基本特征在所有真核蛋白激酶中都是保守的，因此通常认为同一化合物会以相似的方式与不同的蛋白激酶结合。抑制剂4,5,6,7-四溴苯并三唑（TBB）是蛋白激酶CK2的选择性抑制剂（IC50为1.6微摩尔）（萨诺等人，（2001年）《欧洲生物化学学会联合会快报》496, 44 - 48）。其他三种激酶[细胞周期蛋白依赖性蛋白激酶2（CDK2）、磷酸化酶激酶和糖原合酶激酶3β]对TBB的亲和力比对CK2弱约10倍。我们报道了TBB与磷酸化CDK2 - 细胞周期蛋白A复合物的晶体结构，分辨率为2.2埃，并将其相互作用与TBB与CK2结合时观察到的相互作用进行了比较。TBB结合在两种激酶的ATP结合位点。在CDK2中，四个溴原子中的每一个除了与激酶铰链区的主链氧原子或水分子形成极性接触外，还形成了几个范德华接触。TBB与CDK2的结合模式与与CK2的不同。CDK2中的TBB更向N端和C端叶之间的铰链区移位，并相对于CK2中的TBB发生了旋转。CDK2中的ATP结合口袋比CK2中的更宽，导致范德华接触更少，但CK2中的TBB不与铰链接触。这些结构表明，尽管ATP结合口袋具有保守性，但抑制剂能够利用不同的识别特征，使得同一化合物可以以不同的方式与两种不同的激酶结合。
