LaPorte D C, Rosenthal K S, Storm D R
Biochemistry. 1977 Apr 19;16(8):1642-8. doi: 10.1021/bi00627a019.
Polymyxin B was attached to agarose beads by stable covalent bonds and the antimicrobial activity of the immobilized peptide was examined. Polymyxin-agarose inhibited the growth of Escherichia coli and Pseudomonas aeruginosa, but not Bacillus subtilis. In addition, the respiration of E. coli, E. coli spheroplasts, and B. subtilis protoplasts was inhibited by immobilized polymyxin, whereas the respiration of B. subtilis was unaffected by polymyxin-agarose. The activity of polymyxin-agarose was not due to the release of free peptide from the derivative. These data indicate that polymyxin can inhibit the growth and respiration of gram-negative bacteria by interacting with the outer surface of these cells. It is proposed that perturbation of outer membrane structure by polymyxin-agarose indirectly affected the selective permeability of the inner membrane and inhibited respiration. The results of this study emphasize the importance of outer membrane structural integrity for the normal functions of gram-negative bacteria.
多粘菌素B通过稳定的共价键连接到琼脂糖珠上，并检测固定化肽的抗菌活性。多粘菌素-琼脂糖抑制大肠杆菌和铜绿假单胞菌的生长，但不抑制枯草芽孢杆菌的生长。此外，固定化多粘菌素抑制大肠杆菌、大肠杆菌原生质球和枯草芽孢杆菌原生质体的呼吸，而枯草芽孢杆菌的呼吸不受多粘菌素-琼脂糖的影响。多粘菌素-琼脂糖的活性不是由于从衍生物中释放游离肽所致。这些数据表明，多粘菌素可通过与这些细胞的外表面相互作用来抑制革兰氏阴性菌的生长和呼吸。有人提出，多粘菌素-琼脂糖对外膜结构的扰动间接影响内膜的选择性通透性并抑制呼吸。本研究结果强调了外膜结构完整性对革兰氏阴性菌正常功能的重要性。
