Keyloun Katelyn R, Reid Molly C, Choi Ryan, Song Yifan, Fox Anna M W, Hillesland Heidi K, Zhang Zhongsheng, Vidadala RamaSubbaRao, Merritt Ethan A, Lau Audrey O T, Maly Dustin J, Fan Erkang, Barrett Lynn K, Van Voorhis Wesley C, Ojo Kayode K
Center for Emerging and Re-emerging Infectious Diseases (CERID), Division of Allergy and Infectious Diseases, Department of Medicine, University of Washington, Seattle, Seattle, USA.
Department of Biochemistry, University of Washington, Seattle, Seattle, USA.
Parasitology. 2014 Sep;141(11):1499-1509. doi: 10.1017/S0031182014000857. Epub 2014 Jun 13.
Specific roles of individual CDPKs vary, but in general they mediate essential biological functions necessary for parasite survival. A comparative analysis of the structure-activity relationships (SAR) of Neospora caninum, Eimeria tenella and Babesia bovis calcium-dependent protein kinases (CDPKs) together with those of Plasmodium falciparum, Cryptosporidium parvum and Toxoplasma gondii was performed by screening against 333 bumped kinase inhibitors (BKIs). Structural modelling and experimental data revealed that residues other than the gatekeeper influence compound-protein interactions resulting in distinct sensitivity profiles. We subsequently defined potential amino-acid structural influences within the ATP-binding cavity for each orthologue necessary for consideration in the development of broad-spectrum apicomplexan CDPK inhibitors. Although the BKI library was developed for specific inhibition of glycine gatekeeper CDPKs combined with low inhibition of threonine gatekeeper human SRC kinase, some library compounds exhibit activity against serine- or threonine-containing CDPKs. Divergent BKI sensitivity of CDPK homologues could be explained on the basis of differences in the size and orientation of the hydrophobic pocket and specific variation at other amino-acid positions within the ATP-binding cavity. In particular, BbCDPK4 and PfCDPK1 are sensitive to a larger fraction of compounds than EtCDPK1 despite the presence of a threonine gatekeeper in all three CDPKs.
单个钙依赖蛋白激酶（CDPK）的具体作用各不相同，但总体而言，它们介导寄生虫生存所必需的基本生物学功能。通过针对333种碰撞激酶抑制剂（BKI）进行筛选，对犬新孢子虫、柔嫩艾美耳球虫和牛巴贝斯虫的钙依赖蛋白激酶（CDPK）与恶性疟原虫、微小隐孢子虫和刚地弓形虫的钙依赖蛋白激酶的构效关系（SAR）进行了比较分析。结构建模和实验数据表明，除了守门人残基外，其他残基也会影响化合物与蛋白质的相互作用，从而产生不同的敏感性谱。我们随后确定了每个直系同源物在ATP结合腔内潜在的氨基酸结构影响，这对于开发广谱顶复门CDPK抑制剂时需要考虑。尽管BKI文库是为特异性抑制甘氨酸守门人CDPKs而开发的，对苏氨酸守门人人类SRC激酶的抑制作用较低，但一些文库化合物对含丝氨酸或苏氨酸的CDPKs具有活性。CDPK同源物对BKI的不同敏感性可以基于疏水口袋的大小和方向差异以及ATP结合腔内其他氨基酸位置的特定变异来解释。特别是，尽管所有三种CDPKs都存在苏氨酸守门人，但BbCDPK4和PfCDPK1对更大比例的化合物敏感，而EtCDPK1则不然。
