Wnek A P, Jacobson L A
Arch Biochem Biophys. 1985 Aug 15;241(1):106-17. doi: 10.1016/0003-9861(85)90367-4.
After an energy source shift-down, Escherichia coli accumulates 70 S ribosome-mRNA complexes ("70 S monosomes"). The monosome mRNA strands are predominantly primary transcription products with purine nucleoside 5'-triphosphate and 5'-diphosphate termini present at a 1:2 ratio. The number-average chain length is 564 +/- 30 nucleotides, indicating that the population represents primarily monocistronic mRNAs. Digestions with endonucleases and exonucleases indicate that the ribosomes lie near the 5' ends of the mRNA strands and that the majority of the mRNA strands contain 5'-proximal "leader" sequences (average 10 nucleotides) outside the protective boundary of the ribosome. These data are consistent with the hypothesis that the increased functional stability of mRNA in down-shifted cells may result from protection by bound ribosomes of endonuclease-susceptible site(s) near the 5' ends of the mRNA strands.
在能源供应下调后，大肠杆菌会积累70S核糖体-mRNA复合物（“70S单体”）。单体mRNA链主要是初级转录产物，嘌呤核苷5'-三磷酸和5'-二磷酸末端的比例为1:2。数均链长为564±30个核苷酸，表明该群体主要代表单顺反子mRNA。用内切核酸酶和外切核酸酶进行的消化表明，核糖体位于mRNA链的5'端附近，并且大多数mRNA链在核糖体的保护边界之外含有5'-近端“前导”序列（平均10个核苷酸）。这些数据与以下假设一致：下调细胞中mRNA功能稳定性的增加可能是由于结合的核糖体对mRNA链5'端附近的内切核酸酶敏感位点的保护作用。
