Identification of an RNA-protein bridge spanning the ribosomal subunit interface
Identification of an RNA-protein bridge spanning the ribosomal subunit interface
复制标题
DOI：
10.1126/science.285.5436.2133
复制
发表时间：
1999-09-24
期刊：
影响因子：
56.9
通讯作者：
Noller, HF
中科院分区：
文献类型：
--
作者：
Culver, GM;Cate, JH;Noller, HF
70S核糖体的7.8埃晶体结构揭示了一个离散的双螺旋桥（B4），从50S亚基伸出，与30S亚基接触。初步建模研究将其接触位点定位在平台底部附近，与核糖体蛋白S15的结合位点。来自铁（II）的定向羟基自由基探测，铁（II）与23S核糖体RNA结构域II的715环中的S15特异性切割核苷酸相连，该结构域II是23S核糖体RNA中由30S亚基足迹的已知位点之一。重建研究表明，715环的保护，但没有其他30 S依赖性保护，与30 S亚基中S15的存在相关。715环通过结合游离S15至50S亚基而被特异性保护。此外，先前确定的结构的同源茎环从U2小核RNA密切配合的电子密度的桥梁。
The 7.8 angstrom crystal structure of the 70S ribosome reveals a discrete double-helical bridge (B4) that projects from the 50S subunit, making contact with the 30S subunit. Preliminary modeling studies Localized its contact site, near the bottom of the platform, to the binding site for ribosomal protein S15. Directed hydroxyl radical probing from iron(II) tethered to S15 specifically cleaved nucleotides in the 715 Loop of domain II of 23S ribosomal RNA, one of the known sites in 23S ribosomal RNA that are footprinted by the 30S subunit. Reconstitution studies show that protection of the 715 Loop, but none of the other 30S-dependent protections, is correlated with the presence of S15 in the 30S subunit. The 715 loop is specifically protected by binding free S15 to 50S subunits. Moreover, the previously determined structure of a homologous stem-loop from U2 small nuclear RNA fits closely to the electron density of the bridge.