Chittum H S, Champney W S
Department of Biochemistry, J.H. Quillen College of Medicine, East Tennessee State University, Johnson City 37614, USA.
Curr Microbiol. 1995 May;30(5):273-9. doi: 10.1007/BF00295501.
Erythromycin and other macrolide antibiotics have been examined for their effects on ribosome assembly in growing Escherichia coli cells. Formation of the 50S ribosomal subunit was specifically inhibited by erythromycin and azithromycin. Other related compounds tested, including oleandomycin, clarithromycin, spiramycin, and virginiamycin M1, did not influence assembly. Erythromycin did not promote the breakdown of ribosomes formed in the absence of the drug. Two erythromycin-resistant mutants with alterations in ribosomal proteins L4 and L22 were also examined for an effect on assembly. Subunit assembly was affected in the mutant containing the L22 alteration only at erythromycin concentrations fourfold greater than those needed to stop assembly in wild-type cells. Ribosomal subunit assembly was only marginally affected at the highest drug concentration tested in the cells that contained the altered L4 protein. These novel results indicate that erythromycin has two effects on translation, preventing elongation of the polypeptide chain and also inhibiting the formation of the large ribosomal subunit.
已对红霉素和其他大环内酯类抗生素对生长中的大肠杆菌细胞核糖体组装的影响进行了研究。红霉素和阿奇霉素特异性抑制50S核糖体亚基的形成。所测试的其他相关化合物，包括竹桃霉素、克拉霉素、螺旋霉素和维吉尼亚霉素M1，均不影响组装。红霉素不会促进在无药物情况下形成的核糖体的分解。还研究了两个核糖体蛋白L4和L22发生改变的红霉素抗性突变体对组装的影响。仅在红霉素浓度比野生型细胞中阻止组装所需浓度高四倍时，含有L22改变的突变体中的亚基组装才受到影响。在含有改变的L4蛋白的细胞中，在测试的最高药物浓度下，核糖体亚基组装仅受到轻微影响。这些新结果表明，红霉素对翻译有两种作用，即阻止多肽链的延伸以及抑制大核糖体亚基的形成。
