人巨细胞病毒PPUL44蛋白核定位信号结合多肽氨基酸序列分析

Amino acid sequence analysis of peptides that can react to the nuclear localization signals of human Cytomegalovirus PPUL44

目的 寻找与人巨细胞病毒 (HCMV)PPUL44蛋白核定位信号 (NLS)具有较强结合能力的多肽 ,研究这些多肽的氨基酸序列特点。方法 采用合成的HCMVPPUL44NLSA和NLSB分别在一个随机多肽文库中筛选出与NLS具有结合能力的克隆 ,用四色荧光自动测序的方法测定上述克隆的DNA序列 ,对这些克隆的多肽氨基酸序列进行同源性比较 ,并与蛋白质文库中已知蛋白的氨基酸序列进行比较。结果 与HCMVPPUL44NLSA具有结合能力的多肽 (bNLSApep)的氨基酸序列与细胞输入蛋白Importinα亚单位的氨基酸具有较高的同源序列 ,其中bNLSApep48氨基酸序列AVVTPVLTEILK与lmportinα亚单位的Arm7区的第 18至 2 9氨基酸序列ANIFPVLTEILQ具有极高的相似性 ;bNLSBpep39氨基酸序列则与lmportinα亚单位的全部 8个Arm区的第 10至 2 1氨基酸的同源序列相似。结论 HCMVPPUL44NLSA可能是lmportinα亚单位针对HCMVPPUL44蛋白的特异性识别位点 ,与lmportinα亚单位Arm 7区结合 ;而HCMVPPUL44NLSB则为lmportinα亚单位的非特异性识别位点。

Objective To find the peptides that have strong binding ability to the nuclear localization signals (NLS) of human Cytomegalovirus (HCMV) PPUL44 protein, and to analyze their amino acid sequences. Methods Peptide clones that have binding ability to the NLSs were selected from a random peptide display library by using synthesized HCMV PPUL44 NLSA and NLSB respectively. The DNA sequences of these clones were detected by using “ABI Prism BigDye TM Terminator Cycle Sequencing Ready Reaction Kit”. The amino acid sequences of the clones were analyzed for their homology, and the homologous sequences were compared with known sequences in protein bank.Results The peptides that can bind to the HCMV PPUL44 NLSA(named as bNLSApep) have higher homologous amino acid sequence to importin α subunit, the bNLSApep48 sequence AVVTPVLTEILK is more similar to the sequence of the importin α subunit Arm 7 from amino acid 18 to 29, ANIFPVLTEILQ; The bNLSBpep 39 is similar to the sequence of all 8 Arm regions of importin α subunit from amino acid 10 to 21. Conclusion It is possible that the HCMV PPUL44 NLSA is a specific recognition site by importin α subunit, it can bind to the Arm 7 region of importin α subunit; HCMV PPUL44 NLSB is a non\|specific recognition site for importin α subunit. This study provided an experimental data for the proposal that the Arm repeat region of importin α subunit is the binding region of NLS.