Chu Y G, Wollenzien P L, Cantor C R
Department of Human Genetics and Development, Columbia University, New York, New York 10032.
J Biomol Struct Dyn. 1983 Dec;1(3):647-56. doi: 10.1080/07391102.1983.10507472.
E. coli 30S ribosomes in the inactive conformation were irradiated at 390 nm in the presence of 4'-aminomethyl-4,5',8-trimethylpsoralen (AMT). This produces monoadducts in which AMT is attached to only one strand of an RNA duplex region. After unbound AMT was removed, some ribosomes were activated and then subjected to 360 nm irradiation; others were reirradiated without activation. Electron microscopic examination of 16S rRNA extracted from these two samples showed covalent rRNA loops indicative of rRNA crosslinks. The general pattern of loops closely matched that seen previously after direct psoralen crosslinking of 30S particles. However, the frequency of occurrence of one major class of loops formed by crosslinks between residues near position 500 and the 3' end was substantially lower for the activated samples, implying that the structure of the 16S rRNA in active and inactive 30S particles is different.
在4'-氨甲基-4,5',8-三甲基补骨脂素（AMT）存在的情况下，处于无活性构象的大肠杆菌30S核糖体在390nm波长下受到辐照。这会产生单加合物，其中AMT仅连接到RNA双链区域的一条链上。去除未结合的AMT后，一些核糖体被激活，然后进行360nm辐照；其他核糖体则未经激活再次辐照。对从这两个样品中提取的16S rRNA进行电子显微镜检查，发现了表明rRNA交联的共价rRNA环。环的总体模式与之前对30S颗粒直接进行补骨脂素交联后观察到的模式非常匹配。然而，对于激活后的样品，由500位附近残基与3'端之间交联形成的一类主要环的出现频率显著降低，这意味着活性和无活性30S颗粒中16S rRNA的结构不同。
