分子动力学模拟研究二硫键对抗菌肽MDP-2结构的影响

MD Study of the Effect of Disulfide Bonds on the Structure of Antibacterial Peptide MDP-2

人工设计合成的抗菌肽MDP-2含有4个半胱氨酸残基形成2对二硫键,其具有较高的抑菌活性。为了研究2对二硫键结构是否为MDP-2发挥抑菌活性所必须,采用分子动力学模拟对含Cys1-Cys10与Cys3-Cys8间2对二硫键的抗菌肽MDP-2、含有Cys1-Cys10间二硫键的MDP-2.1与含有Cys3-Cys8间二硫键的MDP-2.2、不含二硫键的MDP-2.3进行模拟,分析含不同二硫键数目情况下MDP-2的结构稳定性。研究结果表明含有Cys1-Cys10残基间二硫键的MDP-2.1具有更为稳定的二级结构和更大溶液可及性表面积。因此,Cys1-Cys10残基间的二硫键对抗菌肽MDP-2保持?茁-发夹二级结构具有重要作用,Cys3-Cys8残基间的二硫键没有明显作用。

The artificially designed antibacterial peptide MDP-2 contained four cysteine residues and formed two pairs of disulfide bonds.In order to investigate whether the two pairs of disulfide bonds were necessary for the antibacterial activity of MDP-2,molecular dynamics simulations were performed on MDP-2 contained two pairs of disulfide bonds between Cys1-Cys10 and Cys3-Cys8,MDP-2.1 contained disulfide bonds between Cys1-Cys10,MDP-2.2 contained disulfide bonds between Cys3-Cys8 and MDP-2.3 without disulfide bonds.The structural stability of MDP-2 with different numbers of disulfide bonds was analysed.The results showed that MDP-2.1 contained disulfide bonds between Cys1-Cys10 residues had a more stable secondary structure and a larger solution accessible surface area.Therefore,the disulfide bond between Cys1-Cys10 residues was crucial for the satabilization of the second structure of the antimicrobial peptide MDP-2,while the disulfide bond between Cys3-Cys8 residues shows no significant effect.