Department of Molecular and Structural Biochemistry, North Carolina State University, Raleigh, NC 27695-7622, USA.
Nucleic Acids Res. 2010 May;38(9):3094-105. doi: 10.1093/nar/gkp1253. Epub 2010 Jan 27.
Aminoglycosides antibiotics negate dissociation and recycling of the bacterial ribosome's subunits by binding to Helix 69 (H69) of 23S rRNA. The differential binding of various aminoglycosides to the chemically synthesized terminal domains of the Escherichia coli and human H69 has been characterized using spectroscopy, calorimetry and NMR. The unmodified E. coli H69 hairpin exhibited a significantly higher affinity for neomycin B and tobramycin than for paromomycin (K(d)s = 0.3 +/- 0.1, 0.2 +/- 0.2 and 5.4 +/- 1.1 microM, respectively). The binding of streptomycin was too weak to assess. In contrast to the E. coli H69, the human 28S rRNA H69 had a considerable decrease in affinity for the antibiotics, an important validation of the bacterial target. The three conserved pseudouridine modifications (Psi1911, Psi1915, Psi1917) occurring in the loop of the E. coli H69 affected the dissociation constant, but not the stoichiometry for the binding of paromomycin (K(d) = 2.6 +/- 0.1 microM). G1906 and G1921, observed by NMR spectrometry, figured predominantly in the aminoglycoside binding to H69. The higher affinity of the E. coli H69 for neomycin B and tobramycin, as compared to paromomycin and streptomycin, indicates differences in the efficacy of the aminoglycosides.
氨基糖苷类抗生素通过与 23S rRNA 的 helix 69（H69）结合来否定细菌核糖体亚基的解离和再循环。已经使用光谱学、量热法和 NMR 对各种氨基糖苷类药物对化学合成的大肠杆菌和人 H69 的末端结构域的差异结合进行了表征。未修饰的大肠杆菌 H69 发夹对新霉素 B 和妥布霉素的亲和力明显高于巴龙霉素（K(d)s = 0.3 +/- 0.1、0.2 +/- 0.2 和 5.4 +/- 1.1 microM，分别）。链霉素的结合太弱，无法评估。与大肠杆菌 H69 相反，人 28S rRNA H69 对这些抗生素的亲和力显着降低，这是对细菌靶标的重要验证。大肠杆菌 H69 环中发生的三个保守假尿嘧啶修饰（Psi1911、Psi1915、Psi1917）影响解离常数，但不影响巴龙霉素结合的化学计量（K(d) = 2.6 +/- 0.1 microM）。通过 NMR 光谱观察到的 G1906 和 G1921 在 H69 与氨基糖苷类药物的结合中起主要作用。与巴龙霉素和链霉素相比，大肠杆菌 H69 对新霉素 B 和妥布霉素的亲和力更高，表明氨基糖苷类药物的疗效存在差异。
