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Structure and functions of a very small tetraheme protein -Molecular mechanism of bioremediation-

极小的四血红素蛋白的结构和功能-生物修复的分子机制-

基本信息

批准号：
10044072
负责人：
AKUTSU Hideo
金额：
$ 1.86万
依托单位：
Yokohama National University
依托单位国家：
日本
项目类别：
Grant-in-Aid for Scientific Research (B).
财政年份：
1998
资助国家：
日本
起止时间：
1998 至 1999
项目状态：
已结题

来源：
https://kaken.nii.ac.jp/grant/KAKENHI-PROJECT-10044072/
关键词：
cytochrome cィイD23ィエD2 tetraheme protein Nuclear Magnetic Resonance redox potential over expression system electron transfer electron transport protein シトクロム Cgf C_3 CgbC_3 チヘムタンパク質

项目摘要

The most remarkable characteristic of many Shewanella species is their ability to reduce insoluble metal oxides, including iron, and manganese. S. putrefaciens strain MR1 was specifically isolated as a metal oxide (iron and manganese) reducing organism, and shown to couple the reduction of metal oxides to the oxidation of organic carbon. The ability of Shewanella species to grow with a variety of different electron acceptors having redox potentials from +0.8 V (oxygen) to about 0 (elemental sulfur) implies that this bacterium is able to adjust to growth conditions through changes in the activity and/or the composition of the electron transport chain. Cytochromes are abundant in Shewanella and have been implicated in the reduction of metal oxides. The redox behavior of a tetraheme protein, cytochrome cィイD23ィエD2 was investigated in this work. The macroscopic and microscopic redox potentials were determined at pH 9. Although they are low in comparison with other cytochromes, they are higher than the redox potentials of cytochrome cィイD23ィエD2 from Desulfovibrio vulgaris Miyazaki F (DvMF). DvMF cytochrome cィイD23ィエD2 gene was successfully expressed in a facultative aerobe, Shewanella putrefaciens MR-I, under anaerobic, microaerobic, and aerobic conditions with good yields. A derivative of the broad-host-range plasmid pRK415 containing the cytochrome cィイD23ィエD2, genes from DvMF was used for transformation of S. putrefaciens MR-1, resulting in the production of holocytochrome cィイD23ィエD2 that was indistinguishable from that produced by D. vulgaris Miyazaki F.

许多希瓦氏菌物种最显著的特征是它们能够还原不溶的金属氧化物，包括铁和锰。腐败链霉菌MR1是一种金属氧化物(铁和锰)还原微生物，具有金属氧化物还原和有机碳氧化的偶联作用。希瓦氏菌能够在氧化还原电位从+0.8V(氧气)到约0(元素硫)的各种不同的电子受体上生长，这意味着该细菌能够通过改变电子传输链的活性和/或组成来适应生长条件。希瓦氏菌中含有丰富的细胞色素，与金属氧化物的还原有关。本工作研究了四铁血红素蛋白细胞色素cィイD23ィエD2的氧化还原行为。宏观和微观氧化还原电位在pH为9时测定，虽然与其他细胞色素相比较低，但高于宫崎氏弧菌细胞色素cィイD23ィエD2(DvMF)的氧化还原电位。在厌氧、微好氧和好氧条件下，DvmF细胞色素cィイD23ィエD2基因在兼性好氧菌腐败希瓦氏杆菌MR-I中成功表达，产量较高。将含有细胞色素cィイD23ィエD2基因的广宿主质粒pRK415的衍生体用于腐败链霉菌MR-1的转化，得到了与宫崎氏假单胞菌几乎没有区别的全细胞色素cィイD23ィエD2。