Blood: FXII and peptide progenitors and gC1qR/C1QBP/P32 asymmetrical assembly are subject to variable structure regulation

The contact system, also known as the plasma kinetics release enzyme-kinpeptide system, consists of factor XII (FXII), kinetic release enzyme (PK) and cofactor kinegen (HK)Spherical C1q receptors (gC1qR) have been shown to interact with FXII and HKKaira et alfound that FXII Fiber Protein Type II Domain (FnII) combined with gC1qR in a Zn2-dependent manner, determining the crystal structure of the compoundThe FXIIFnII and gC1qR triples combine in asymmetric manner, and the Arg36 and Arg65 residues form contact with two different negatively charged pocketsgC1qR's residual Asp185 and His187 are positioned in a Zn2 plus near the FXII binding site, and a comparison with the ligand-free gC1qR crystal structure found that the yin ion G1-ring becomes orderly after binding to FXIIFnIIThe change of the image of the Zn2 plus combined site area reveals the structural basis of zn2 plus adjusted FXII bindingthe mutagenics combined with SPR showed that gC1qR Zn2 plus sites contributed to FXII binding, and plasma-based tests showed that gC1qR stimulated clotting in a way that FXII relied onThe combination analysis of HK Domain 5 (HKD5) and gC1qR shows that each triplebody has only one junction of high affinitymutagenic study found a key G3-ring located at the center of the gC1qR tripolymer, revealing that spatial astleration is the mechanism of HKD5 asymmetric bindingGel filtration experiments show that gC1qR combines FXII and HK into a higher-order 500kDa ternary compoundin general, this study supports the conclusion that extracellular gC1qR can act as a partner of contact factor aggregation, which may be a prelude to the initiation of cascade reactions and intracellular pathways that drive the generation of slow-stimulating peptides