Highly Selective, Irreversible Protein Kinase Inhibitors

真核蛋白激酶催化酪氨酸、丝氨酸和苏氨酸残基的磷酸化，基本上调节所有的细胞过程。因此，蛋白激酶是多种人类疾病的重要治疗靶点。人类基因组编码大约500个蛋白激酶，所有这些蛋白激酶都有一个高度保守的ATP结合位点。几乎所有已知的小分子激酶抑制剂都以这个位点为靶点，这是一个包含所有必要催化残基的深疏水裂缝。因此，蛋白激酶化学生物学中的一个中心问题涉及到选择性抑制剂的开发，这些抑制剂可以区分这些相似的结合位点。 这项建议描述了一种结构生物信息学方法，用于设计选择性的、不可逆的激酶抑制剂。从人类基因组中所有蛋白激酶结构域的序列比对开始，我们鉴定了在ATP结合位点内的唯一位置拥有半胱氨酸残基的一小部分。 这种半胱氨酸的位置，通过我们对多个晶体结构的分析预测，形成了设计新型亲电抑制剂的起点。我们假设，添加到适当支架上的亲电取代基将使半胱氨酸迅速烷基化，从而阻断ATP结合部位并不可逆转地抑制酶。该项目的长期目标是开发高选择性、细胞渗透性的抑制剂，以解开这些蛋白激酶的确切细胞角色，被认为调节转录、凋亡、染色体分离和胞质分裂等各种过程。

Eukaryotic protein kinases catalyze the phosphorylation of tyrosine, serine, and threonine residues and regulate essentially all cellular processes. Protein kinases are therefore important therapeutic targets for a variety of human diseases. The human genome encodes approximately 500 protein kinases, all of which share a highly conserved ATP binding site. Nearly all known small-molecule kinase inhibitors target this site, a deep hydrophobic cleft containing all of the essential catalytic residues. Thus, a central problem in the chemical biology of protein kinases concerns the development of selective inhibitors that discriminate among these similar binding sites. This proposal describes a structural bioinformatics approach for the design of selective, irreversible kinase inhibitors. Beginning with a sequence alignment of all protein kinase domains in the human genome, we identified a small subset that possess a cysteine residue in a unique location within the ATP binding site. The location of this cysteine, predicted by our analysis of multiple crystal structures, forms the starting point for the design of novel, electrophilic inhibitors. We hypothesize that an electrophilic substituent appended to an appropriate scaffold will rapidly alkylate the cysteine, thereby blocking the ATP binding site and irreversibly inhibiting the enzyme. The long-term goal of this project is to develop highly selective, cell-permeable inhibitors to unravel the precise cellular roles of these protein kinases, thought to regulate processes as diverse as transcription, apoptosis, chromosome segregation, and cytokinesis.