Lysine-oriented charges trigger the membrane binding and activity of nukacin ISK-1
Lysine-oriented charges trigger the membrane binding and activity of nukacin ISK-1
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DOI：
10.1128/aem.00678-06
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发表时间：
2006-09-01
影响因子：
4.4
通讯作者：
Sonomoto, Kenji
中科院分区：
文献类型：
--
作者：
Asaduzzaman, Sikder M.;Nagao, Jun-ichi;Sonomoto, Kenji
评价了努卡星ISK-1及其片段和突变体的抗菌活性和膜结合，以描述控制结构-功能关系的决定因素。尾区（nukacin（1-7））和环区（nukacin（7-27））显示没有抗菌活性，并且彼此之间或甚至对nukacin ISK-1也没有协同作用。在N末端缺失三个赖氨酸的片段（nukacin（4-27））和在N末端用丙氨酸替换三个赖氨酸的突变体（K1-3A nukacin ISK-1）都赋予非常低的活性（比nukacin ISK-1低32倍），并且对nukacin ISK-1也表现出类似的拮抗作用。在N末端添加两个赖氨酸残基（+2K nukacin ISK-1）没有提供进一步增加的抗菌活性。表面等离子体共振传感图和动力学速率常数测定的BIAcore生物传感器表明，nukacin ISK-1具有显着更高的结合亲和力，阴离子模型膜比两性离子模型膜。Nukacin ISK-1和+2K Nukacin ISK-1的高亲和力表明了类似的强结合反应和动力学趋势，但尾区、环区、Nukacin（4-27）和K1-3A Nukacin ISK-1与阴离子模型膜没有结合。因此，我们的研究结果表明，nukacin ISK-1的完整结构是其充分活性所必需的，其中N-末端三个赖氨酸残基在与靶膜的静电结合中起着至关重要的作用，因此nukacin ISK-1发挥其有效抗菌活性的能力。
The antibacterial activities and membrane binding of nukacin ISK-1 and its fragments and mutants were evaluated to delineate the determinants governing structure-function relationships. The tail region (nukacin(1-7)) and ring region (nukacin(7-27)) were shown to have no antibacterial activity and also had no synergistic effect on each other or even on nukacin ISK-1. Both a fragment with three lysines in the N terminus deleted (nukacin(4-27)) and a mutant with three lysines in the N terminus replaced with alanine (K1-3A nukacin ISK-1) imparted very low activity (32-fold lower than nukacin ISK-1) and also exhibited a similar antagonistic effect on nukacin ISK-1. Addition of two lysine residues at the N terminus (+2K nukacin ISK-1) provided no further increased antibacterial activity. Surface plasmon resonance sensorgrams and kinetic rate constants determined by a BIAcore biosensor revealed that nukacin ISK-1 has remarkably higher binding affinity to anionic model membrane than to zwitterionic model membrane. Similar trends of strong binding responses and kinetics were indicated by the high affinities of nukacin ISK-1 and +2K nukacin ISK-1, but there was no binding of tail region, ring region, nukacin(4-27), and K1-3A nukacin ISK-1 to the anionic model membrane. Our findings therefore suggest that the complete structure of nukacin ISK-1 is necessary for its full activity, in which the N-terminus three lysine residues play a crucial role in electrostatic binding to the target membrane and therefore nukacin ISK-1's ability to exert its potent antibacterial activity.