An intercistronic region and ribosome-binding site in bacterial messenger RNA.
An intercistronic region and ribosome-binding site in bacterial messenger RNA.
复制标题
细菌信使 RNA 中的顺反子间区域和核糖体结合位点。
DOI：
10.1073/pnas.72.6.2399
复制
发表时间：
1975
影响因子：
11.1
通讯作者：
C. Yanofsky
中科院分区：
文献类型：
--
作者：
T. Platt;C. Yanofsky
从大肠杆菌32- p标记色氨酸操纵子mRNA中分离到一个长约220个核苷酸的信使RNA片段。在trpB末端和trpA起始处进行点突变，发现核苷酸发生了变化；因此mRNA片段必须包含trpB-trpA顺子间区。根据trpB和trpA蛋白的氨基酸序列，大多数核苷酸序列可以分配到结构基因的特定位置。在体外，核糖体与这段mRNA结合，并保护其免受核酸酶攻击，该区域长约40个核苷酸，包含一个中央AUG密码子。这个AUG 3'侧的三联体密码子对应trpA蛋白的前7个氨基酸；5'侧的密码子对应trpB蛋白的最后6个氨基酸。trpB的翻译由单个UGA密码子终止，该密码子与trpA AUG起始密码子UGAUG重叠。因此，未翻译的“顺反子间”区域仅由两个核苷酸组成。跨越该区域的RNA序列无疑具有两个功能，即指定核糖体识别信号以及编码氨基酸序列。
A messenger RNA fragment about 220 nucleotides long has been isolated from 32-P-labeled tryptophan operon mRNA of Escherichia coli. When point mutations at the end of trpB and the beginning of trpA were introduced, the resulting nucleotide changes were found; hence the mRNA fragment must include the trpB-trpA intercistronic region. Most of the nucleotide sequences can be assigned to specific locations in the structural genes, based on the amino-acid sequences of the trpB and trpA proteins. In vitro, ribosomes bind to this piece of mRNA and protect from nuclease attack a region about 40 nucleotides long, containing a central AUG codon. The triplet codons to the 3' side of this AUG correspond to the first seven amino acids of the trpA protein; the codons to the 5' side correspond to the last six amino acids of the trpB protein. Translation of trpB is terminated by single UGA codon, which overlaps the trpA AUG initiation codon: UGAUG. Thus the untranslated "intercistronic" region consists of only two nucleotides. The RNA sequence spanning this region undoubtedly fulfills two functions, specifying ribosome recognition signals as well as encoding amino-acid sequences.