Neelima S, Archana K, Athira P P, Anju M V, Anooja V V, Bright Singh I S, Philip Rosamma
Department of Marine Biology, Microbiology & Biochemistry, Cochin University of Science and Technology, Cochin, 682016, India.
National Centre for Aquatic Animal Health, Cochin University of Science and Technology, Cochin, 682016, India.
J Genet Eng Biotechnol. 2021 May 12;19(1):71. doi: 10.1186/s43141-021-00175-6.
The concern regarding a post-antibiotic era with increasing drug resistance by pathogens imposes the need to discover alternatives for existing antibiotics. Antimicrobial peptides (AMPs) with their versatile therapeutic properties are a group of promising molecules with curative potentials. These evolutionarily conserved molecules play important roles in the innate immune system of several organisms. The β-defensins are a group of cysteine rich cationic antimicrobial peptides that play an important role in the innate immune system by their antimicrobial activity against the invading pathogens. The present study deals with a novel β-defensin isoform from the red-toothed trigger fish, Odonus niger. Total RNA was isolated from the gills, cDNA was synthesized and the β-defensin isoform obtained by polymerase chain reaction was cloned and subjected to structural and functional characterization in silico.
A β-defensin isoform could be detected from the gill mRNA of red-toothed trigger fish, Odonus niger. The cDNA encoded a 63 amino acid peptide, β-defensin, with a 20 amino acid signal sequence followed by 43 amino acid cationic mature peptide (On-Def) having a molecular weight of 5.214 kDa and theoretical pI of 8.89. On-Def possessed six highly conserved cysteine residues forming disulfide bonds between C1-C5, C2-C4, and C3-C6, typical of β-defensins. An anionic pro-region was observed prior to the β-defensin domain within the mature peptide. Clustal alignment and phylogenetic analyses revealed On-Def as a group 2 β-defensin. Furthermore, it shared some structural similarities and functional motifs with β-defensins from other organisms. On-Def was predicted to be non-hemolytic with anti-bacterial, anti-viral, anti-fungal, anti-cancer, and immunomodulatory potential.
On-Def is the first report of a β-defensin from the red-toothed trigger fish, Odonus niger. The antimicrobial profile showed the potential for further studies as a suitable candidate for antimicrobial peptide therapeutics.
对病原体耐药性不断增加的后抗生素时代的担忧促使人们需要寻找现有抗生素的替代品。具有多种治疗特性的抗菌肽（AMPs）是一类具有治疗潜力的有前景的分子。这些进化上保守的分子在多种生物体的先天免疫系统中发挥重要作用。β-防御素是一组富含半胱氨酸的阳离子抗菌肽，通过对入侵病原体的抗菌活性在先天免疫系统中发挥重要作用。本研究涉及来自红牙扳机鱼（Odonus niger）的一种新型β-防御素异构体。从鳃中分离总RNA，合成cDNA，并将通过聚合酶链反应获得的β-防御素异构体进行克隆，并在计算机上进行结构和功能表征。
从红牙扳机鱼（Odonus niger）的鳃mRNA中可检测到一种β-防御素异构体。该cDNA编码一个63个氨基酸的肽，即β-防御素，其具有一个20个氨基酸的信号序列，随后是一个43个氨基酸的阳离子成熟肽（On-Def），分子量为5.214 kDa，理论pI为8.89。On-Def具有六个高度保守的半胱氨酸残基，在C1-C5、C2-C4和C3-C6之间形成二硫键，这是β-防御素的典型特征。在成熟肽的β-防御素结构域之前观察到一个阴离子前区。Clustal比对和系统发育分析显示On-Def属于2型β-防御素。此外，它与来自其他生物体的β-防御素具有一些结构相似性和功能基序。On-Def预计无溶血作用，具有抗菌、抗病毒、抗真菌、抗癌和免疫调节潜力。
On-Def是关于红牙扳机鱼（Odonus niger）β-防御素的首次报道。抗菌谱显示其作为抗菌肽治疗的合适候选物有进一步研究的潜力。
