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并基本上调节所有细胞过程。因此，蛋白激酶是多种人类疾病的重要治疗靶标。人类基因组编码大约500种蛋白激酶，所有这些蛋白激酶都具有高度保守的ATP结合位点。几乎所有已知的小分子激酶抑制剂都靶向这个位点，这是一个含有所有必需催化残基的深疏水裂缝。因此，蛋白激酶化学生物学的一个中心问题是开发能够区分这些相似结合位点的选择性抑制剂。 该建议描述了一种用于设计选择性、不可逆激酶抑制剂的结构生物信息学方法。从人类基因组中所有蛋白激酶结构域的序列比对开始，我们确定了一小部分在ATP结合位点内的独特位置具有半胱氨酸残基。 通过我们对多个晶体结构的分析预测，这种半胱氨酸的位置形成了设计新型亲电抑制剂的起点。我们假设，一个亲电子取代基附加到一个适当的支架将迅速烷基化的半胱氨酸，从而阻断ATP结合位点和不可逆地抑制酶。该项目的长期目标是开发高度选择性的细胞渗透性抑制剂，以揭示这些蛋白激酶的精确细胞作用，这些蛋白激酶被认为调节转录，凋亡，染色体分离和胞质分裂等多种过程。

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.