PDZK1和PDZK2结合特性的比较

Comparison of PDZK1 and PDZK2 and their binding properties

目的比较同一种属同一家族两种相近的简单接头蛋白PDZ结构域结合配体的特性。方法采用酵母双杂交筛选新型随机多肽文库联合高效验证筛选特定PDZ配体库,分别鉴定PDZK1-PDZ1和PDZK2-PDZ1结合线性多肽序列,分析发现两种PDZ结构域结合共有序列特性。通过生物信息学方法比对PDZ结构域,确定结构域中与配体相互接触面位点,进而详细比较这两个相似结构域结合特性的区别及其产生原因。结果分别获得PDZK1-PDZ1和PDZK2-PDZ1的结合特性,发现两者的共有序列分别可以归纳为-[S/T]-x-Φ和-[S/T]-[K/R/H]-[F/L],两个PDZ结构域间相互作用接触面位点大部分相似,主要差异表现在接触面位点比对中的37～45氨基酸序列,特别是42位氨基酸(F和H)差异较大。结论成功鉴定PDZK1-PDZ1和PDZK2-PDZ1结构域的结合特性,发现了这两个PDZ结构域及其结合配体特性的差异。

Objective Compare PDZs from two homologous simple adaptor proteins PDZK1 and PDZK2 and their binding properties.Methods We used yeast two-hybrid screening of a random peptide library and high throughput validation screening of a specialized PDZ ligand candidate library to systematically and comprehensively identify PDZ ligands,consensus-binding sequences were deduced from sequence alignment of positive clones.Two PDZs were compared by structure-guided sequence alignment.The binding properties of the PDZ domains were analyzed.Results The C-terminal consensus sequence for binding to PDZK1-PDZ1 and PDZK2-PDZ1 were——x-Φ and—— respectively.The contacting residues on the PDZ domains are similar,only the amino acids between 37 and 45 were different,especially at the 42 position（F vs H）.Conclusion Homologous PDZK1 and PDZK2 have different contacting residues and different binding properties.