Sermkaew Namfa, Atipairin Apichart, Krobthong Sucheewin, Aonbangkhen Chanat, Yingchutrakul Yodying, Uchiyama Jumpei, Songnaka Nuttapon
School of Pharmacy, Walailak University, Thasala, Nakhon Si Thammarat 80160, Thailand.
Drug and Cosmetics Excellence Center, Walailak University, Thasala, Nakhon Si Thammarat 80160, Thailand.
Antibiotics (Basel). 2024 Sep 5;13(9):846. doi: 10.3390/antibiotics13090846.
This study focused on the discovery of the antimicrobial peptide (AMP) derived from mangrove bacteria. The most promising isolate, NNS5-6, showed the closest taxonomic relation to , with the highest similarity of 74.9%. The AMP produced by NNS5-6 exhibited antibacterial activity against various Gram-negative pathogens, especially and . The peptide sequence consisted of 13 amino acids and was elucidated as Val-Lys-Gly-Asp-Gly-Gly-Pro-Gly-Thr-Val-Tyr-Thr-Met. The AMP mainly exhibited random coil and antiparallel beta-sheet structures. The stability study indicated that this AMP was tolerant of various conditions, including proteolytic enzymes, pH (1.2-14), surfactants, and temperatures up to 40 °C for 12 h. The AMP demonstrated 4 µg/mL of MIC and 4-8 µg/mL of MBC against both pathogens. Time-kill kinetics showed that the AMP acted in a time- and concentration-dependent manner. A cell permeability assay and scanning electron microscopy revealed that the AMP exerted the mode of action by disrupting bacterial membranes. Additionally, nineteen biosynthetic gene clusters of secondary metabolites were identified in the genome. NNS5-6 was susceptible to various commonly used antibiotics supporting the primary safety requirement. The findings of this research could pave the way for new therapeutic approaches in combating antibiotic-resistant pathogens.
本研究聚焦于从红树林细菌中发现抗菌肽（AMP）。最具潜力的分离株NNS5-6与 显示出最接近的分类关系，相似度最高达74.9%。NNS5-6产生的AMP对多种革兰氏阴性病原体具有抗菌活性，尤其是 和 。该肽序列由13个氨基酸组成，经鉴定为Val-Lys-Gly-Asp-Gly-Gly-Pro-Gly-Thr-Val-Tyr-Thr-Met。该AMP主要呈现无规卷曲和反平行β-折叠结构。稳定性研究表明，这种AMP能耐受多种条件，包括蛋白水解酶、pH值（1.2 - 14）、表面活性剂以及高达40℃持续12小时的温度。该AMP对两种病原体的最低抑菌浓度（MIC）为4 µg/mL，最低杀菌浓度（MBC）为4 - 8 µg/mL。时间杀菌动力学表明，该AMP的作用具有时间和浓度依赖性。细胞通透性测定和扫描电子显微镜显示，该AMP通过破坏细菌膜发挥作用方式。此外，在基因组中鉴定出19个次生代谢物的生物合成基因簇。NNS5-6对多种常用抗生素敏感，符合基本的安全性要求。本研究结果可为对抗抗生素耐药病原体的新治疗方法铺平道路。
