IDENTIFICATION OF A RECEPTOR-BINDING REGION IN THE CORE SEGMENT OF THE HUMAN ANAPHYLATOXIN C5A

In order to identify regions of C5a that contribute to receptor bindin g and functional activity of the anaphylatoxin, a series of peptides w as synthesized in which core segments have been attached to C-terminal segments via native peptidic or disulfide bonds. It has been found th at residues Arg(40) and Arg(46) in the loop-3 region of the core induc e a 1000-fold increase in the affinity of the disordered C-terminal se gment of C5a. The results obtained from this work lead to the conclusi on that the loop-3 region is most likely the core binding site of C5a.