Molecular properties of cytochrome c oxidase in Ascaris respiratory chain and its response to oxygen tension

蛔虫呼吸链细胞色素c氧化酶的分子特性及其对氧张力的响应

基本信息

批准号：
10670239
负责人：
TAKAMIYA Shinzaburo
金额：
$ 2.11万
依托单位：
Juntendo University
依托单位国家：
日本
项目类别：
Grant-in-Aid for Scientific Research (C)
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-10670239/
关键词：
Ascaris suum respiratory chain cytochrome c oxidase response to oxygen tension C. elegans Rhodoquinone fumarate reductase complex II ミトコンドリア

项目摘要

1.Achievement in l998: The respiratory chain of Caenorhabditis elegans was characterized in mitochondria isolated from aerobically grown nematodes. Nematode mitochondria contain ubiquinone-9 as a major component and rhodoquinone-9 as a minor component. The ratio of ubiquinone-9/rhodoquinone-9 is higher in C. elegans mitochondria than in mitochondria from second-stage larvae of Ascaris suum, the free-living stage of porcine gut-dwelling nematode. The individual oxidoreductase activities comprising succinate-oxidase and the amount of substrate-reducible cytochromes are comparable to those of mitochondria from second-stage larvae of A. suum. The specific activity of fumarate reductase is lower in C. elegans mitochondria than in mitochondria from second-stage larvae of A. suum, but still higher than in mammalian mitochondria. These results indicate that the free-living nematode C. elegans is capable of synthesizing rhodoquinone, as distinguished from aerobic mammalian species, although its mitochondria appear more aerobic than A. suum larval mitochondria.2. Achievement in 1999: The Ip subunit of Ascaris suum larval complex II was characterized because Northern hybridization showed that the adult Ip also is expressed in the larvae. The Ip of larval complex II was recognized by the antibody against adult Ip, and was indistinguishable from the adult Ip by peptide mapping. The N-terminal 42 amino acid sequence of Ip in the larval complex II purified by DEAE-cellulofine column chromatography was identical to that of the mature form of the adult Ip. Furthermore, the amino acid composition of larval Ip determined by micro-analysis on a PVDF membrane is almost the same as that of adult Ip. These results suggest that the two different stage-specific forms of the A. suum complex II share a common Ip subunit, even though the adult enzyme functions as a fumarate reductase, while larval enzyme acts as a succinate dehydrogenase.

1.1998年的成果：从需氧生长的线虫中分离出的线粒体中表征了秀丽隐杆线虫的呼吸链。线虫线粒体的主要成分为泛醌-9，次要成分为红醌-9。秀丽隐杆线虫线粒体中泛醌-9/红醌-9的比例高于猪蛔虫第二阶段幼虫（猪肠道线虫的自由生活阶段）的线粒体。包括琥珀酸氧化酶的个体氧化还原酶活性和底物可还原细胞色素的量与来自猪蛔虫第二阶段幼虫的线粒体的活性相当。线虫线粒体中富马酸还原酶的比活性低于猪线虫第二阶段幼虫的线粒体，但仍高于哺乳动物线粒体。这些结果表明，与需氧哺乳动物物种不同，自由生活的线虫秀丽隐杆线虫能够合成玫瑰醌，尽管其线粒体比猪线虫幼虫线粒体更需氧。2． 1999年的成就：由于Northern杂交显示成虫Ip也在幼虫中表达，因此对猪蛔虫幼虫复合体II的Ip亚基进行了表征。幼虫复合物 II 的 Ip 被针对成虫 Ip 的抗体识别，并且通过肽图谱无法将其与成虫 Ip 区分开。通过 DEAE-cellulofine 柱层析纯化的幼虫复合体 II 中 Ip 的 N 端 42 个氨基酸序列与成熟形式的成虫 Ip 相同。此外，通过PVDF膜上的微量分析测定幼虫Ip的氨基酸组成与成虫Ip几乎相同。这些结果表明，尽管成虫酶充当富马酸还原酶，而幼虫酶充当琥珀酸脱氢酶，但两种不同阶段特异性形式的 A. suum 复合体 II 共享一个共同的 Ip 亚基。