Role of the distal hinge region of C1‐inhibitor in the regulation of C1s activity

摘要

>A synthetic peptide corresponding to residues 448–459 of C1-inhibitor (C1-inh) binds to C1s, is a non-competitive inhibitor of C1s activity and prevents formation of an SDS-stable C1s–C1-inh complex. Substitutions of residues Q452, Q453 or F455 in this peptide resulted in loss of C1s binding and inhibitory activity of the peptide. NMR analysis of the peptide showed an area of well-defined structure from E450 to F455. The side chains of Q452, Q453 and Q455 were exposed to the solvent and therefore available for C1s binding. The defined structure in the peptide is compatible with our computer model of the serpin domain of C1-inh.