As a major component of the innate immune system ,human antimicrobial peptide LL -37 plays an important role in the protection of human resistance to disease .Residues 17-29 (FK -13) are consid‐ered as the core area of LL -37 antimicrobial activity .LL -37 can damage bacterial membrane with nega‐tive .LL -37 antimicrobial activity is closely related to secondary structure changes .In this work ,we studied the interaction between antimicrobial fragment FK -13 and of the bacterial membrane POPG by molecular dynamics simulation .The results show that the Coulomb interaction causes FK -13 close to the surface of the membrane rapidly and FK -13 can carpet the surface of the membrane .FK -13 has par‐tial helix structure when it interacts with membrane .In addition ,FK -13 can cause disturbance and de‐struction of the membrane and it is beneficial to exert antimicrobial activity .The residues 18 ~ 22 are key residues in the membrane function .So the work is useful for us not only understand the changes of FK -13 conformation and its damage to the membrane but also provide a theoretical basis for FK -13 as a ther‐apeutic application .%作为先天免疫系统的主要成分，人源抗菌肽L L －37在保护人类对抗疾病方面起了重要的角色。残基肽段17－29（FK －13）被认为是L L －37行使抗菌功能的核心区域，L L －37能对带负电的细菌膜产生破坏作用，其抗菌活性与二级结构的变化情况有关。用分子动力学模拟的方法研究了抗菌肽段 FK －13与带负电的细菌膜PO PG的相互作用。研究发现，库仑作用会使FK －13快速靠近膜的表面，然后像地毯一样覆盖在膜的表面；FK －13仍旧保持部分螺旋结构，并通过引起膜的扰动对膜产生破坏，以实现抗菌功能，而残基18～22是与膜作用的关键残基。研究FK －13与膜的相互作用，不仅可以从原子层面上了解L L －37对细菌膜作用的机理，也为基于L L －37设计高效抗菌药物提供帮助。
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