Wang Ruining, Guo Junqing, Li Ge, Wang Xun, Yang Jifei, Li Qingmei, Zhang Gaiping
Key Laboratory of Animal Immunology, Henan Academy of Agricultural Sciences, Zhengzhou 450002, China.
College of Veterinary Medicine, Henan University of Animal Husbandry and Economics, Zhengzhou 450046, China.
Vet Sci. 2024 Jan 8;11(1):24. doi: 10.3390/vetsci11010024.
The bovine IgG1 Fc receptor (boFcγRIII) is a homologue to human FcγRIII (CD16) that binds bovine IgGI with medium-low affinity. In order to identify the Fc-binding site on the bovine IgG1 Fc receptor (boFcγRIII), peptides derived from the second extracellular domain (EC2) of boFcγRIII were synthesized and conjugated with the carrier protein. With a Dot-blot assay, the ability of the peptides to bind bovine IgG1 was determined, and the IgG1-binding peptide was also identified via truncation and mutation. The minimal peptide AQRVVN corresponding to the sequence 98-103 of boFcγRIII bound bovine IgG1 in Dot-blot, suggesting that it represents a linear ligand-binding site located in the putative A-B loop of the boFcγRIII EC2 domain. Mutation analysis of the peptide showed that the residues of Ala, Gln, Val, Val and Asn within the Fc-binding site are critical for IgG1 binding on boFcγRIII. The functional peptide identified in this paper is of great value to the IgG-Fc interaction study and FcR-targeting drug development.
牛IgG1 Fc受体（boFcγRIII）是人类FcγRIII（CD16）的同源物，与牛IgG1具有中低亲和力。为了鉴定牛IgG1 Fc受体（boFcγRIII）上的Fc结合位点，合成了源自boFcγRIII第二个细胞外结构域（EC2）的肽，并将其与载体蛋白偶联。通过斑点印迹分析，确定了肽与牛IgG1结合的能力，还通过截短和突变鉴定了IgG1结合肽。对应于boFcγRIII序列98-103的最小肽AQRVVN在斑点印迹中与牛IgG1结合，表明它代表位于boFcγRIII EC2结构域假定A-B环中的线性配体结合位点。对该肽的突变分析表明，Fc结合位点内的丙氨酸、谷氨酰胺、缬氨酸、缬氨酸和天冬酰胺残基对于boFcγRIII上的IgG1结合至关重要。本文鉴定的功能性肽对IgG-Fc相互作用研究和FcR靶向药物开发具有重要价值。
