文章摘要
刘芳;韩倩云;倪元颖.膜结合态多酚氧化酶生物学信息分析[J].中国食品学报,2019,19(9):237-244
膜结合态多酚氧化酶生物学信息分析
Bioinformatics Information Analysis of Membrane-bound Polyphenol Oxidase
  
DOI:
中文关键词: 苹果  膜结合态多酚氧化酶  二级结构  跨膜  亚细胞定位
英文关键词: apple  membrane-bound polyphenol oxidase  secondary structural  trans-membrane  subcellular localization
基金项目:国家自然科学基金项目(31571849,31801596)
作者单位
刘芳;韩倩云;倪元颖 西北农林科技大学食品科学与工程学院陕西杨凌712100中国农业大学食品科学与营养工程学院北京100083 
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中文摘要:
      苹果中膜结合态多酚氧化酶(mPPO)占苹果多酚氧化酶的90%左右,而国内外对mPPO性质及作用知之甚少。本文在前期获得的mPPO一级序列基础上,利用预测技术对mPPO进行信息学分析(包括氨基酸组成及性质、二级结构、跨膜结构、亚细胞定位等),为研究mPPO结构提供新思路,为探索mPPO在苹果采后生理中的作用提供理论基础。结果表明:mPPO氨基酸含量最多的为Thr(8.7%),其次为Asp(7.8%)和Leu(7.8%),不含有Pyl和Sec。对PPO功能起重要作用的His含量为2.5%。mPPO中暴露表面的残基为45.74%,埋藏内部的氨基酸残基为47.08%。mPPO的理论稳定指数为41.72,为不稳定蛋白。mPPO二级结构中的α-螺旋为18.67%,β-折叠为23.33%,无规卷曲为58.00%,不含310螺旋、Pi螺旋、β-桥、β-转角等结构。富士苹果mPPO位于叶绿体膜上,为疏水性膜整合蛋白,其大部分肽段位于细胞质中,肽段的1~39氨基酸残基为信号肽,82~97为N-端的一段跨膜肽段(由外到内),而548~567为C端的一段跨膜肽段(由内到外)。
英文摘要:
      Membrane-bound polyphenol oxidase (mPPO) in Fuji apple (Malus domestica Borkh. cv. Red Fuji) (mPPO) accounted for about 90% of apple polyphenol oxidase, while there was little knowledge about mPPO properties and functions. In this paper, we analyzed bioinformatics of mPPO (including amino acid composition and properties, secondary structure, trans-membrane structure, subcellular localization, etc.) based on the prophase of mPPO primary sequence, using prediction technology, in order to provide new ideas to study mPPO structure and provide a theoretical basis for exploring the role of mPPO in apple postharvest physiology. The results showed that: the highest level of amino acid content in mPPO was Thr(8.7%), followed by the Asp (7.8%) and Leu (7.8%). There were no Pyl and Sec. Histidine (His) Play an important role on mPPO function while its content is just 2.5%. From the result of amino acid composition, the proportion of hydrophobic amino acids in mPPO was above 40% and the exposed surfaces (exposed) residues was 45.74%. Theory of mPPO stability index was 41.72, which indicates that the mPPO was an unstable protein. The secondary structure of mPPO showed that the alpha helix was 18.67%, and beta folding structure content was 23.33%, the rest of the random coil was 58.00%. mPPO protein did not contain 310 spiral, spiral, Pi beta bridge, beta Angle, bending structure, and other structures. The calculation of sub-cellular localization indicated that mPPO from Fuji was a hydrophobic membrane protein in chloroplast with a 39 amino acid residues signal peptide and two extracellular membrane peptides (82-97 for N-, 548-567 for C-).
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