论文部分内容阅读
目的 分析人N 甲基 D 门冬氨酸受体 (NMDAR)主亚基NR1a上两个受体激活相关多肽P1、P2的抗原性及其理化特性。方法 用GOLDKEY软件从蛋白质数据库中调出人NR1a分子的氨基酸序列 ,分别在其第一、第三跨膜域前后逆向、顺向截取 15 1和 14 4个氨基酸长度的多肽片段P1与P2 ,选取Hopp&Woods与Kyte亲水性、Janin表面可及性、Karplus Schulz主链柔韧性及Welling抗原性等参数予以多参数分析 ,采用Prosite程序与Chou Fasman方法比较其氨基酸位点与二级结构特征 ,以此为基础综合判定P1与P2片段的抗原位点并与已有的实验结果相比较。结果 P1、P2多肽片段上可能分别有 6和 7个 8～ 15aa长序列具有良好的抗原性。P1相关序列主要分布于其氨基端 ,与配体结合关键氨基酸残基相距较远。P2上的相关序列分布较均匀 ,包含有受体激活重要相关位点或与配体结合关键氨基酸残基距离较近。P2片段的总体抗原性、亲水性与可及性均强于P1,尤以其近膜的 15个残基为著。P1、P2多肽片段均含有一定数量的 β 转角 ,但P1片段含有较多的半胱氨酸残基和无规卷曲 ,而P2片段则含有较多的芳香族残基并以α螺旋结构为主。结论 人NMDAR主亚基NR1a上的两个受体激活相关多肽P1、P2均具有一定数量的抗原位点 ,与P1相比较 ,P2可能更易成为NMDAR免?
Objective To analyze the antigenicity and physico-chemical properties of two receptor-activating peptides P1 and P2 on human NR1a, a major subunit of N-methyl-D-aspartate receptor (NMDAR). Methods The amino acid sequence of human NR1a was extracted from the protein database using GOLDKEY software. The P1 and P2 fragments of 15 1 and 14 4 amino acids in length were reversely and forwardly intercepted in the first and third transmembrane domains respectively. Hopp & Woods and Kyte hydrophilicity, Janin surface accessibility, Karplus Schulz backbone flexibility and Welling antigenicity and other parameters to be multiparametric analysis, Prosite program and Chou Fasman method to compare the amino acid position and secondary structure characteristics, as a Based on the comprehensive determination of the P1 and P2 fragments of antigenic sites and compared with the existing experimental results. Results There were 6 and 7 8 ~ 15aa long sequences in P1 and P2 polypeptide fragments with good antigenicity. The P1-related sequences are mainly distributed at the amino terminus, which is far from the key amino acid residues of ligand binding. The related sequences on P2 are more evenly distributed and contain important related sites for receptor activation or closer to the key amino acid residues for ligand binding. The overall antigenicity, hydrophilicity and accessibility of P2 fragments are stronger than that of P1, especially the 15 residues of its proximal membrane. The P1 and P2 polypeptide fragments all contain a certain number of β-turn, but the P1 fragment contains more cysteine residues and random coils, whereas the P2 fragment contains more aromatic residues and is mainly composed of α-helices. . Conclusions There are a number of antigenic sites in P1 and P2 of two receptor activating peptides on human NR1a, the main subunit of NMDAR. P2 may be more easily NMDAR than P1.