Novodvorski Alex, Kong Avalene, Yu Hai, Lepp Dion, Brott Ashley, Carere Jason, Seah Stephen, Gong Joshua
Guelph Research and Development Centre, Agriculture and Agri-Food Canada, Guelph, Ontario, N1G 5C9, Canada.
Department of Molecular and Cellular Biology, University of Guelph, Guelph, Ontario, N1G 2W1, Canada.
Microbiology (Reading). 2025 Jul;171(7). doi: 10.1099/mic.0.001573.
HG88 was isolated from ileal mucosa samples of egg layer hens that were raised without the use of antibiotics. Its cell-free supernatant (CFS) was found to inhibit the growth of , the causative agent of necrotic enteritis in chickens. The inhibitory compound was determined to be proteinaceous due to its susceptibility to protease digestion. The antimicrobial activity was specific towards , as the CFS did not inhibit the growth of Gram-positive or Gram-negative bacteria across nine different species and two yeast fungi. Separation of proteins from the CFS followed by peptide mass fingerprinting and genomic analyses of the strain enabled the identification of a putative antibacterial peptide with an export signal for secretion from the cell. The peptide from HG88, named IP, has sequence similarity to bacterial SH3 domains that are known to bind to the peptide portion of peptidoglycan. The gene encoding this peptide was cloned, and the peptide was purified from recombinant as an N-terminal His-tagged peptide. The IP with or without the His-tag inhibited the growth of with a minimum bactericidal concentration of ~57.0 or 39.1 µg ml, respectively. The 3D structure of IP was also predicted using AlphaFold 2.0.
HG88是从未使用抗生素饲养的蛋鸡回肠黏膜样本中分离出来的。发现其无细胞上清液（CFS）可抑制鸡坏死性肠炎病原体的生长。由于其对蛋白酶消化敏感，确定该抑制性化合物为蛋白质类。抗菌活性对具有特异性，因为CFS在九个不同物种和两种酵母真菌中均未抑制革兰氏阳性或革兰氏阴性细菌的生长。从CFS中分离蛋白质，随后进行肽质量指纹分析和该菌株的基因组分析，从而鉴定出一种具有细胞分泌输出信号的假定抗菌肽。来自HG88的肽名为IP，与已知与肽聚糖的肽部分结合的细菌SH3结构域具有序列相似性。克隆了编码该肽的基因，并从重组体中纯化出该肽作为N端带His标签的肽。带有或不带有His标签的IP均抑制的生长，其最小杀菌浓度分别约为57.0或39.1μg/ml。还使用AlphaFold 2.0预测了IP的三维结构。
