Alexander R W, Cooperman B S
Department of Chemistry, University of Pennsylvania, Philadelphia 19104-6323, USA.
Biochemistry. 1998 Feb 10;37(6):1714-21. doi: 10.1021/bi972280+.
We report the synthesis of a radioactive, photolabile oligodeoxyribonucleotide probe and its exploitation in identifying 50 S ribosomal subunit components neighboring its target site, nucleotides 803-811 in 23 S rRNA. Photolysis of the complex formed between the probe and 50 S subunits leads to site-specific probe photoincorporation into proteins L15, L17, and L20, labeled to greater extents, and L13 and L21, labeled to lesser extents. Portions of each of these proteins thus lie within 23 A of nucleotide U803. These results lead us to conclude that nucleotides 803-811 fall on the side of the L13-L17-L20-L21 protein cluster [Walleczek et al. (1988) EMBO J. 7, 3571-3576] that points from the back of the 50 S particle toward the peptidyl transferase center within the 50 S subunit. Such placement is consistent with the observation that an oligoDNA probe directed to nucleotides 803-811 decreases P-site binding of tRNA [Hill et al. (1990) Biochim. Biophys. Acta 1050, 45-50].
我们报道了一种放射性、光不稳定的寡脱氧核糖核苷酸探针的合成及其在鉴定与它的靶位点相邻的50 S核糖体亚基组分中的应用，该靶位点是23 S rRNA中的核苷酸803 - 811。探针与50 S亚基形成的复合物的光解导致位点特异性的探针光掺入到蛋白质L15、L17和L20中（标记程度更高）以及蛋白质L13和L21中（标记程度较低）。因此，这些蛋白质中的每一种的部分区域位于核苷酸U803的23 Å范围内。这些结果使我们得出结论，核苷酸803 - 811位于L13 - L17 - L20 - L21蛋白质簇[Walleczek等人（1988年）《欧洲分子生物学组织杂志》7，3571 - 3576]的一侧，该簇从50 S颗粒的背面指向50 S亚基内的肽基转移酶中心。这种位置与以下观察结果一致，即针对核苷酸803 - 811的寡DNA探针会降低tRNA在P位点的结合[Hill等人（1990年）《生物化学与生物物理学报》1050，45 - 50]。
