Dang H, Ellis S R
Department of Biochemistry, University of Louisville, KY 40292.
Nucleic Acids Res. 1990 Dec 11;18(23):6895-901. doi: 10.1093/nar/18.23.6895.
We have purified a small subunit mitochondrial ribosomal protein, MRPS28p, from the yeast, Saccharomyces cerevisiae. Sequence from the amino terminus of MRPS28p was used to design a degenerate oligonucleotide that was complementary to the MRPS28 gene. The MRPS28 gene was isolated and its sequence determined. The MRPS28 sequence encodes a 28 kDa protein that has a region of homology with ribosomal protein S15 of E. coli. This region spans the entire length of the E. coli protein, but as MRPS28p is larger, includes only the portion of the MRPS28p sequence from amino acids 150 to 238. Based on this homology, we predict that MRPS28p, like E. coli S15, interacts directly with small subunit rRNA and functions as an early protein in ribosome assembly. Cells carrying a disrupted chromosomal copy of MRPS28 are unable to respire and spontaneously lose portions of their mitochondrial genomes at a high frequency. These phenotypes are consistent with an essential role for MRPS28p in the assembly and/or function of the mitochondrial ribosome.
我们从酿酒酵母中纯化出了一种线粒体核糖体小亚基蛋白MRPS28p。利用MRPS28p氨基末端的序列设计了一种与MRPS28基因互补的简并寡核苷酸。分离出MRPS28基因并测定了其序列。MRPS28序列编码一种28 kDa的蛋白质，该蛋白质与大肠杆菌的核糖体蛋白S15有一个同源区域。这个区域跨越了大肠杆菌蛋白质的全长，但由于MRPS28p更大，只包括MRPS28p序列中从氨基酸150到238的部分。基于这种同源性，我们预测MRPS28p与大肠杆菌S15一样，直接与小亚基rRNA相互作用，并在核糖体组装中作为早期蛋白发挥作用。携带MRPS28染色体拷贝被破坏的细胞无法进行呼吸，并且会高频自发丢失其线粒体基因组的部分片段。这些表型与MRPS28p在线粒体核糖体组装和/或功能中的重要作用一致。
