孤啡肽OFQ的溶液构象研究  

Study on the Solution Conformation of Orphanin FQ

作　　者：何发虎[1] 张琪[1] 石嘉豪[2] 崔大敷 吴厚铭[1] 

机构地区：[1]中国科学院上海有机化学研究所生命有机化学国家重点实验室,上海200032 [2]中国科学院上海生物化学和细胞生物学研究所,上海200031

出　　处：《化学学报》2003年第7期1101-1107,共7页Acta Chimica Sinica

基　　金：国家自然科学基金(No.20132030)

摘　　要：应用近代NMR波谱技术对孤啡肽OFQ及其片段OFQ_(8-17)的溶液结构进行了比较研究,测定了孤啡肽OFQ和片段OFQ_(8-17)在H_2O和TFE/H_2O两种溶剂条件下的2D-DQF-COSY,2D-TOCSY,2D-NOESY(ROESY)谱,完成了它们氨基酸残基的自旋系统识别和序列特异性归属,获得分子中质子化学位移的完全归属,根据NOE特征和主链偶合常数等结构参数确定了它们的特征二级结构,以NOE提供的距离约束,进行了距离几何,分子力学和分子动力学模拟,得到了孤啡肽OFQ在不同溶剂条件下的溶液结构.在H_2O溶剂中,孤啡肽OFQ在G3-F4-T5-G6处形成一复合型转角结构.在TFE/H_2O溶剂中,OFQ整个分子形成两亲性α-螺旋结构.而孤啡肽片段OFQ_(8-17)在这两种环境中均为伸展的无规结构.孤啡肽OFQ在类似膜环境(TFE/H_2O)下的α-螺旋结构可能为其活性构象.A comparative study on the solution conformation between OFQ and its fragment OFQ(8similar to17) Was Carried Out using 2D NMR experiments both in H2O and TFE/H2O. After completion of amino acid spin system recognition and the sequence-specific assignments, the regular secondary structure of OFQ and OFQ(8similar to17) in different solvents were deduced from NOE patterns, and backbone coupling constants ((3)J(HN-Halpha)). The solution structure of OFQ both in H2O and TFE/H2O was obtained using distance constraints derived from NOE cross peaks and dihedral angles constraints and was refined by DG, RMD and SA calculations. The structural feature of OFQ in water was characterized by a mixing type turn in segment of Gly3-Phe4-The5-Gly6 at 278 K. While the conformation of OFQ was identified as an amphipathic alpha-helix in TFE/H2O. However, OFQ(8similar to17) demonstrated random conformation both in water and in TFE/H2O. These results revealed that OFQ assumes amphipathic helical conformation in the membrane-like circumstances involved in the interaction with the receptor.

关 键 词：孤啡肽 OFQ 溶液构象 核磁共振 二级结构 溶液结构 

分 类 号：Q516[生物学—生物化学]