Protein Engineering for New Functional Hemoproteins Based on Module Substitution

基于模块替换的新型功能性血红素蛋白的蛋白质工程

基本信息

批准号：
07409003
负责人：
MORISHIMA Isao
金额：
$ 19.65万
依托单位：
KYOTO UNIVERSITY
依托单位国家：
日本
项目类别：
Grant-in-Aid for Scientific Research (A)
财政年份：
1995
资助国家：
日本
起止时间：
1995 至 1997
项目状态：
已结题

来源：
https://kaken.nii.ac.jp/grant/KAKENHI-PROJECT-07409003/
关键词：
Module Exon Shaffling Globin エクソンジャフリング

项目摘要

The primary results in this research project are as followa :(1)Module Substitution in Globins and Peroxidases. The structural and functional properties of the module-substituted globins and peroxidases have been characterized. Most of the module-substituted proteins exhibited highly destabilized protein structure, probably due to the missing or severe perturbation in the key interactions between the modules. The destabilized protein structure also interfered the formation of the specific dimers or tetramers in globins and enzymatic activity in peroxidases. It can be, therefore, concluded that the module-module interactions are also essential to design new stable and functional proteins as well as the module substitution.(2)Identification of New Module Structure in Globins. The amino acid substituteions based on the structural unit of wchic boundaries are located at the middle of the conventional modules have revealed that the module previously proposed can be divided into new and smaller structural units. In this research project, I focused upon one of the newly identified structural units, which includes the iron-liganded histidine and about 20 amino acid residues in the proximal site, "sub-module m6". The substitution of the sub-module m6 in globins drastically affect the electronic state of heme and configuration of the iron-liganded histidine, indicating that the sub-module m6 would be a "heme binding modules" respondible for the heme binding structure.

本研究项目的主要成果如下：(1)球蛋白和过氧化物酶的模块替换。模块取代的球蛋白和过氧化物酶的结构和功能特性已得到表征。大多数模块取代的蛋白质表现出高度不稳定的蛋白质结构，可能是由于模块之间的关键相互作用缺失或严重扰动。不稳定的蛋白质结构还干扰球蛋白中特定二聚体或四聚体的形成以及过氧化物酶中的酶活性。因此，可以得出结论，模块与模块之间的相互作用对于设计新的稳定和功能性蛋白质以及模块替换也至关重要。(2)球蛋白中新模块结构的鉴定。基于位于常规模块中间的边界结构单元的氨基酸取代表明，先前提出的模块可以分为新的和更小的结构单元。在这个研究项目中，我重点研究了新发现的结构单元之一，其中包括铁配体组氨酸和近端位点的约 20 个氨基酸残基，“子模块 m6”。球蛋白中子模块m6的取代极大地影响了血红素的电子状态和铁配体组氨酸的构型，表明子模块m6将是对血红素结合结构敏感的“血红素结合模块”。