Endou K, Endoh S, Matsuoka M, Nakajima Y
Division of Microbiology, Hokkaido Institute of Pharmaceutical Sciences, Japan.
Biol Pharm Bull. 1993 Mar;16(3):328-30. doi: 10.1248/bpb.16.328.
Staphylococcus aureus S704 and 8325MMT7 show constitutive resistance to macrolide antibiotics such as erythromycin (EM), oleandomycin, spiramycin, rosamicin and josamycin, except for tylosin, rokitamycin (RKM), and mycinamicin as well as lincosamide and streptogramin type B antibiotics (PM-resistance). Whenever 70S ribosomes from either of them were dissociated into 30S and 50S subunits in a 10-28%(W/W) linear sucrose gradient, the latter subunit was further cleaved into two small apparently equal particles (about 40S). RKM could no longer bind to either of the small particles. A prior exposure of 8325MMT7's 50S subunit to RKM (except EM) did not cause cleavage in any small particles. The largest component (M.W. 33.0kDa) of 50S ribosomal proteins was absent in at least the small particles. The first finding suggests that the lability of the 50S ribosome may be responsible for PM-resistance.
金黄色葡萄球菌S704和8325MMT7对红霉素（EM）、竹桃霉素、螺旋霉素、蔷薇霉素和交沙霉素等大环内酯类抗生素表现出组成型抗性，但对泰乐菌素、罗他霉素（RKM）、麦米诺霉素以及林可酰胺类和B型链阳菌素类抗生素（PM抗性）除外。每当将它们中的任何一个的70S核糖体在10 - 28%（W/W）线性蔗糖梯度中解离成30S和50S亚基时，后者亚基会进一步裂解成两个明显相等的小颗粒（约40S）。RKM无法再与任何一个小颗粒结合。8325MMT7的50S亚基预先暴露于RKM（EM除外）不会导致任何小颗粒发生裂解。至少在小颗粒中不存在50S核糖体蛋白的最大成分（分子量33.0kDa）。第一个发现表明50S核糖体的不稳定性可能是PM抗性的原因。
