Rui Wang, Shiliang Zhou, Xiaomin Peng, Xin-Wen Zhou, Zhi-Qun Xie, Yuxiong Wang, Wei Mo and Min Yu Pages 315 - 325 ( 11 )
TACI is a member of the tumor necrosis factor receptor superfamily and serves as a key regulator of B cell function. The extracellular domain of a typical TNFR contains multiple copies of CRD, which bind in the monomermonomer interfaces of a trimeric ligand. TACI binds to two ligands, APRIL and BAFF, with high affinity and contains two CRD in its extracellular regions, while BCMA and BR3, contain a single or partial CRD for binding the two ligands. However, TACI can be classified as a single CRD receptor because the amino-terminal CRD1 doesnt contribute to ligand binding. To obtain a new variant of TACI possessing higher affinities for binding, we fused a repeat sequence of CRD2 to the N-terminus of the short form of TACI. The new APRIL antagonist peptide, CRD2-shortTACI-Fc, was designed based on the modeling 3-D complex structure of TACI and APRIL. As expected, the purified recombinant CRD2-shortTACI-Fc fusion protein could bind to APRIL in vitro and demonstrated dose-dependent inhibition of APRIL-induced proliferative activity in Raji cells. We found that CRD2-shortTACI-Fc, has a higher affinity for binding to ligands than short-TACI-Fc, which contains a single CRD2.
TACI, CRD2, BAFF, APRIL, affinity, autoimmune disorders, Novagen, DNA ligase, homology modeling, Pichia pastoris
Department of Biochemistry and Molecular Biology, Key Laboratory of Molecular Medicine, the Ministry of Education, Shanghai Medical College.