Previously, we found that ASP-ASP-ASP-TYR (DDDY) from Dendrobium aphyllum has a minimum inhibitory concentration of 36.15 mg/mL against Pseudomonas aeruginosa. Here, we explored the antibacterial mechanism of DDDY and its potential preservation applications. Metabolomic and transcriptomic analyses revealed that DDDY mainly affects genes involved in P. aeruginosa membrane transport and amino acid metabolism pathways. Molecular dynamics simulation revealed that DDDY had a stronger effect on 1-palmitoyl-2-oleoyl-sn-glycero-3-phosphoethanolamine phospholipid membranes than on 1-palmitoyl-2-oleoyl-lecithin or 1-palmitoyl-2-oleoyl phosphatidylglycerol membranes, with high DDDY concentrations displaying stronger efficacy on 1-palmitoyl-2-oleoyl-sn-glycero-3-phosphoethanolamine. Mechanistically, the N-terminal of DDDY first bound to the phospholipid head group, while its C-terminal amino acid residue bound the hydrophobic tail, thereby creating a gap in the membrane when the phospholipids were clustered by hydrogen bonding. Finally, DDDY inhibited the growth of food microorganisms inoculated onto chestnut kernels, suggesting that DDDY is a promising antibacterial agent against multidrug-resistant gram-negative bacteria.

此前，我们发现石斛石斛中的 ASP-ASP-ASP-TYR (DDDY)对铜绿假单胞菌的最低抑菌浓度为 36.15 mg/mL 。在这里，我们探讨了 DDDY 的抗菌机制及其潜在的保存应用。代谢组学和转录组学分析表明，DDDY 主要影响涉及铜绿假单胞菌的基因膜转运和氨基酸代谢途径。分子动力学模拟表明，DDDY 对 1-palmitoyl-2-oleoyl-sn-glycero-3-phosphoethanolamine 磷脂膜的影响比对 1-palmitoyl-2-oleoyl-lecithin 或 1-palmitoyl-2-oleoyl phosphatidylglycerol 膜的影响更强，高浓度 DDDY 对 1-palmitoyl-2-oleoyl-sn-glycero-3-phosphoethanolamine 表现出更强的功效。机械地，NDDDY的-末端首先与磷脂头基结合，而其C-末端氨基酸残基与疏水尾结合，从而当磷脂通过氢键成簇时在膜中产生间隙。最后，DDDY 抑制了接种在栗子上的食品微生物的生长，表明 DDDY 是一种很有前途的抗多重耐药革兰氏阴性菌的抗菌剂。