Alpha-defensin dimers multimerize to form a pore complex

Once adsorbed/inserted into the membrane, alpha defensins are believed to aggregate into pore forming structures. Based on vesicle leakage and dextran permeability experiments, Wimley et al. (1994) proposed a multimeric pore model consisting of 6-8 defensin dimers which come together to form a large pore with inner diameter of 2-2.5nm. More recently using solid-state NMR and artificial lipid bilayers, Zhang et al. (2010) provide evidence of a dimer pore model in which the polar top of the dimer lines an aqueous pore while the hydrophobic bottom faces the lipid chains. Regardless of the exact conformation, the resulting pores then allow the efflux of essential microbial cell components.

一旦被吸附/插入到细胞膜中，α防御素据信会聚集成形成孔隙的结构。基于囊泡泄漏和右旋糖酐渗透性实验，Wimley 等人（1994年）提出了一个由6-8个防御素二聚体组成的寡聚孔隙模型，这些二聚体聚合形成一个大孔隙，其内径约为2-2.5纳米。近期，Zhang 等人（2010年）利用固态核磁共振和人工脂质双层膜技术，提供了关于二聚体孔隙模型的证据，其中二聚体的极性顶端环绕着水孔隙，而疏水性底部则面向脂质链。无论确切的构象如何，这些孔隙随后允许关键微生物细胞成分的流出。