富含蛋白质的线虫线粒体核糖体的分离及理化性质

Isolation and physiochemical properties of protein-rich nematode mitochondrial ribosomes.

作者信息

Zhao Feng, Ohtsuki Takashi, Yamada Koji, Yoshinari Shigeo, Kita Kiyoshi, Watanabe Yoh-Ichi, Watanabe Kimitsuna

机构信息

Department of Integrated Biosciences, University of Tokyo, 5-1-5 Kashiwanoha, Kashiwa, Chiba 277-8562, Japan.

出版信息

Biochemistry. 2005 Jun 28;44(25):9232-7. doi: 10.1021/bi047833c.

DOI:10.1021/bi047833c

PMID:15966747

Abstract

In the present study, mitochondrial ribosomes of the nematode Ascaris suum were isolated and their physiochemical properties were compared to ribosomes of Escherichia coli. The sedimentation coefficient and buoyant density of A. suum mitochondrial ribosomes were determined. The sedimentation coefficient of the intact monosome was about 55 S. The buoyant density of formaldehyde-fixed ribosomes in cesium chloride was 1.40 g/cm(3), which suggests that the nematode mitoribosomes have a much higher protein composition than other mitoribosomes. The diffusion coefficients obtained from dynamic light scattering measurements were (1.48 +/- 0.04) x 10(-)(7) cm(2) s(-)(1) for 55 S mitoribosomes and (1.74 +/- 0.04) x 10(-)(7) cm(2) s(-)(1) for the 70 S E. coli monosome. The diameter of mitoribosomes was measured by dynamic light-scattering analysis and electron microscopy. Though the nematode mitoribosome has a larger size than the bacterial ribosome, it does not differ significantly in size from mammalian mitoribosomes.

摘要

在本研究中，分离了线虫猪蛔虫的线粒体核糖体，并将其理化性质与大肠杆菌的核糖体进行了比较。测定了猪蛔虫线粒体核糖体的沉降系数和浮力密度。完整单核糖体的沉降系数约为55 S。氯化铯中甲醛固定核糖体的浮力密度为1.40 g/cm³，这表明线虫线粒体核糖体的蛋白质组成比其他线粒体核糖体高得多。通过动态光散射测量获得的扩散系数，55 S线粒体核糖体为(1.48±0.04)×10⁻⁷ cm² s⁻¹，70 S大肠杆菌单核糖体为(1.74±0.04)×10⁻⁷ cm² s⁻¹。通过动态光散射分析和电子显微镜测量了线粒体核糖体的直径。虽然线虫线粒体核糖体的尺寸比细菌核糖体大，但与哺乳动物线粒体核糖体的尺寸没有显著差异。