Latinwo L M, Archibold E
Department of Biology, Florida A&M University, Tallahassee 32307.
Biochem Biophys Res Commun. 1993 Dec 30;197(3):1118-25. doi: 10.1006/bbrc.1993.2593.
Our studies on the association of penicillinase plasmid (pI524) DNA with its host bacterial (Staphylococcus aureus) membrane revealed that the membrane-associated forms of this plasmid could be isolated from exponentially grown cells lysed on neutral sucrose gradient. Analysis of putative plasmid-membrane complexes isolated from the clear lysates on sucrose gradients indicated that approximately 23% of plasmid (pI524) DNA was stably associated with the bacterial cell membrane fractions. This suggested that one of the three or four copies of this plasmid per cell was complexed to the cellular membrane. Examination of the effect of various enzymes, e.g., ribonuclease and protease, as well as antibiotics (rifampicin and chloramphenicol), on complexing have shown the possible involvement of protein(s) rather than RNA in mediating the complexing of this plasmid to the cell membrane. The specificity of plasmid pI524 to its host cell membrane was observed in an experiment where R6k was included in binding assay.
我们对青霉素酶质粒（pI524）DNA与其宿主细菌（金黄色葡萄球菌）细胞膜之间关联的研究表明，这种质粒的膜相关形式可以从在中性蔗糖梯度上裂解的指数生长期细胞中分离出来。对从蔗糖梯度上的清亮裂解物中分离出的假定质粒 - 膜复合物的分析表明，约23%的质粒（pI524）DNA与细菌细胞膜组分稳定相关。这表明每个细胞中该质粒的三到四个拷贝之一与细胞膜形成了复合物。对各种酶（如核糖核酸酶和蛋白酶）以及抗生素（利福平和氯霉素）对复合物形成的影响的研究表明，介导该质粒与细胞膜形成复合物的可能是蛋白质而非RNA。在结合试验中加入R6k的实验中观察到了质粒pI524对其宿主细胞膜的特异性。
