The efficacy of the antibacterial peptide, pyrrhocoricin, is finely regulated by its amino acid residues and active domains
The efficacy of the antibacterial peptide, pyrrhocoricin, is finely regulated by its amino acid residues and active domains
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DOI：
10.1007/bf02446518
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发表时间：
2001-01-01
期刊：
影响因子：
--
通讯作者：
Otvos, L
中科院分区：
文献类型：
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作者：
Bencivengo, AM;Cudic, M;Otvos, L
Pyrrhocoricin是一种从昆虫中分离的高效抗菌肽，通过与70 kDa的热休克蛋白DnaK的氨基端结合抑制分子伴侣辅助的蛋白质折叠。C-末端起细胞内递送模块的作用。在目前的研究中，由pyrrhocoricin和相关肽drosocin的推定功能单元组成的嵌合体被制成，并且发现一些混合和匹配的序列保留了它们杀死大肠杆菌、鼠伤寒沙门氏菌和根癌农杆菌的能力。虽然pyrrhocoricin似乎有一个更普遍的药效团，drosocin功能更强大的细胞内交付单位。我们还确定了有效杀死细菌所需的最小长度的pyrrhocoricin。而针对S. typhimurium不能缩短，抗E.大肠杆菌中含有Val 1-Ile 16氨基端片段即可。虽然Val 1不是Asp 2-Pro 10药效团的一部分（它可以被其他残基取代），但它不能被消除，并且显然在定义肽的活性方面发挥重要作用。事实上，当Val 1被赖氨酸取代时，不仅吡咯红菌素杀死敏感菌株的效力显著增加，导致对一些临床菌株最具活性的抗微生物肽，而且修饰的肽还能够杀死铜绿假单胞菌，一种最初在低μ g ml（-1）浓度范围内无反应的细菌。然而，这种取代可能影响与细菌膜的相互作用，而不是与靶蛋白的相互作用，因此Lys 1-pyrrhocoricin肽的主要作用模式可能以膜崩解而不是DnaK抑制为特征。
Pyrrhocoricin, a highly active antibacterial peptide isolated from insects, inhibits chaperone-assisted protein folding via binding to the 70 kDa heat shock protein DnaK with its amino terminal half. The C-terminus functions as an intracellular delivery module. In the current study, chimeras consisting of the putative functional units of pyrrhocoricin and a related peptide, drosocin, were made, and it was found that some mixed and matched sequences retained their ability to kill Escherichia coli, Salmonella typhimurium and Agrobacterium tumefaciens. While pyrrhocoricin appeared to have a more universal pharmacophore, drosocin featured a more robust intracellular delivery unit. We also identified the minimal length of pyrrhocoricin that is needed to efficiently kill bacteria. While for activity against S. typhimurium the peptide could not be shortened, against E. coli it was sufficient to have a Val1-Ile16 amino-terminal fragment. Although Val1 was not part of the Asp2-Pro10 pharmacophore (it could be replaced with other residues), it could not be eliminated and apparently played an important role in defining the activity of the peptide. Indeed, when Val1 was replaced with lysine, not only the efficacy of pyrrhocoricin to kill the sensitive strains increased significantly, resulting in the most active antimicrobial peptide against some clinical strains ever made, but the modified peptide was also able to kill Pseudomonas aeruginosa, an originally unresponsive bacterium in the low mug ml(-1) concentration range. However, this substitution likely influenced the interaction with bacterial membranes rather than that with the target protein, and therefore the dominant mode of action of the Lys1-pyrrhocoricin peptide may feature membrane disintegration instead of DnaK inhibition.