高等学校化学学报 ›› 2018, Vol. 39 ›› Issue (3): 470-475.doi: 10.7503/cjcu20170570

• 有机化学 • 上一篇    下一篇

牡蛎源类蛋白反应修饰肽的分离纯化及肽锌螯合物的结构表征

曹玉惠, 张娟娟, 王再扬, 赵元晖()   

  1. 中国海洋大学食品科学与工程学院, 青岛266003
  • 收稿日期:2017-08-21 出版日期:2018-03-10 发布日期:2018-01-17
  • 作者简介:联系人简介: 赵元晖, 男, 博士, 副教授, 主要从事水产品高值化利用方面的研究. E-mail:zhaoyuanhui@ouc.edu.cn
  • 基金资助:
    山东省自然科基金(批准号: ZR2015CM011)和国家贝类产业技术体系项目(批准号: CARS-49)资助

Separation and Identification of Oyster Peptide Modified by Plastein Reaction and Characterization of Peptide-zinc Complexes

CAO Yuhui, ZHANG Juanjuan, WANG Zaiyang, ZHAO Yuanhui*()   

  1. College of Food Science and Engineering, Ocean University of China, Qingdao 266003, China
  • Received:2017-08-21 Online:2018-03-10 Published:2018-01-17
  • Contact: ZHAO Yuanhui E-mail:zhaoyuanhui@ouc.edu.cn
  • Supported by:
    † Supported by the Natural Science Foundation of Shandong Province, China(No.ZR2015CM011) and the Program of Shellfish Industry Technology System of China(No.CARS-49)

摘要:

以牡蛎为原料制备了类蛋白反应修饰肽, 利用Sephadex G-15凝胶层析柱和反向高效液相色谱(RP-HPLC)等分离技术得到1条锌离子螯合活性为161 mg/g的多肽(Mw=835), 多肽序列为EVPPEEH. 以测得的肽序列为模板合成多肽, 将纯肽与锌离子进行螯合反应制备肽锌螯合物. 螯合物的红外光谱和圆二色光谱表征结果表明, 锌离子主要与多肽链上的羰基氧发生相互作用. 与多肽的空间结构相比, 螯合物的无规则卷曲结构减少, β转角增加而β折叠减少. 由肽锌螯合物的分子模拟和二级质谱结果可知, 多肽与锌离子螯合后有2种空间构象: 一种通过六配位的方式螯合1个锌离子, 其中主要的螯合位点为多肽Val-2和Pro-3或者Clu-5和Clu-6之间的羰基氧; 另一种是通过四配位的方式螯合1个锌离子, 主要的螯合位点为多肽Clu-5和Clu-6之间的羰基氧.

关键词: 类蛋白反应, 螯合活性, 分离纯化, 螯合位点

Abstract:

An oyster peptide modified by plastein reaction was isolated from the modified product using different methods including Sephadex G-15 gelcolumn chromatography and reversed-phase high-performance liquid chromalography(RP-HPLC). The purified peptide was sequenced as EVPPEEH with a zinc chelate activity of 161 mg/g. The peptide sequence was used as template to synthesize the pure peptide which was used to prepare peptide-zinc complexes. The results of infrared spectroscopy and circular dichroism of the complexes showed that the carbonyl oxygen belonging to the peptide chain was the primary binding site for Zn2+. Compared with the pure peptide, the irregular curl and β fold of complexes was reduced while β angle increases. Molecular mechanics simulation experiment and secondary spectrum of complexes showed that there were two kinds of spatial conformation of complexes. One way was to chelate a zinc ion by six coordination where the main chelating site was the carbonyl oxygen between Val-2 and Pro-3 or Clu-5 and Clu-6. The other was to chelate a zinc ion by four coordination where the main chelating site was the carbonyl oxygen between Clu-5 and Clu-6.

Key words: Plastein reaction, Chelate activity, Isolation and purification, Chelate site

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