Jia Yuewen, Liu Yijie, Zhang Wenli, Wang Rongxiao, Sun Yuying, Zhang Jiquan
School of Life Sciences/Hebei Basic Science Center for Biotic Interaction, Hebei University, Baoding, 071002, China.
School of Life Sciences/Hebei Basic Science Center for Biotic Interaction, Hebei University, Baoding, 071002, China; Institute of Life Science and Green Development, Hebei University, Baoding, 071002, China.
Fish Shellfish Immunol. 2025 Feb;157:110116. doi: 10.1016/j.fsi.2025.110116. Epub 2025 Jan 9.
This study investigates an L-type lectin, NdLTL1, derived from Neocaridina denticulata sinensis, emphasizing its role in immune defense through carbohydrate binding and bacterial agglutination. Bioinformatics analysis identified 179 lectin sequences, leading to subsequent investigations into the structure and function of NdLTL1. The open reading frame (ORF) of NdLTL1 spans 966 bp and encodes a protein consisting of 321 amino acids (36.25 kDa), which features a signal peptide, a transmembrane domain and Lectin_leg-like domain. Three-dimensional modeling revealed three antiparallel β-sheets characteristic of Lectin_leg-like domain, confirming evolutionary links with proteins such as VIP36. Protein-carbohydrate and protein-protein interaction studies showed that NdLTL1 binds to both carbohydrates like N-acetylglucosamine, peptidoglycan, lipopolysaccharides (LPS), and mannose, as well as sorting proteins (COPI/COPII). Gene expression analyses indicated that NdLTL1 exhibits the highest expression levels in cardiac tissues and significant upregulation in gills following exposure to Vibrio parahaemolyticus. Recombinant NdLTL1 expressed in Escherichia coli was shown to bind multiple bacterial strains and exhibit calcium-dependent agglutination properties. Enzyme-linked immunosorbent assay (ELISA) confirmed concentration-dependent carbohydrate binding, particularly rapid for LPS. In vitro experiments suggested that recombinant NdLTL1 may promote bacterial growth under nutrient-limited conditions while potentially triggering immune defenses indirectly.
本研究对源自中华新米虾的一种L型凝集素NdLTL1进行了调查，重点研究了其通过碳水化合物结合和细菌凝集在免疫防御中的作用。生物信息学分析鉴定出179个凝集素序列，随后对NdLTL1的结构和功能展开了研究。NdLTL1的开放阅读框（ORF）跨度为966 bp，编码一个由321个氨基酸组成（36.25 kDa）的蛋白质，该蛋白质具有一个信号肽、一个跨膜结构域和Lectin_leg样结构域。三维建模揭示了Lectin_leg样结构域特有的三个反平行β折叠，证实了其与VIP36等蛋白质的进化联系。蛋白质-碳水化合物和蛋白质-蛋白质相互作用研究表明，NdLTL1既能与N-乙酰葡糖胺、肽聚糖、脂多糖（LPS）和甘露糖等碳水化合物结合，也能与分选蛋白（COPI/COPII）结合。基因表达分析表明，NdLTL1在心脏组织中表达水平最高，在暴露于副溶血性弧菌后鳃中显著上调。在大肠杆菌中表达的重组NdLTL1被证明能结合多种细菌菌株，并具有钙依赖性凝集特性。酶联免疫吸附测定（ELISA）证实了其与碳水化合物结合的浓度依赖性，对LPS的结合尤为迅速。体外实验表明，重组NdLTL1在营养受限条件下可能促进细菌生长，同时可能间接触发免疫防御。
