Recombinant CDHR3 proteins.

Bacterially produced CDHR3 fragments (100 pmol) with the indicated C-terminal extensions (A), point mutations (B), or rEC deletions (C) were incubated with C15 virus (10⁷ PFUe). Immunoprecipitation with an α-His mAb was followed by Western analysis for bound proteins (α-His for CDHR3, and α-C15). As labeled here, “rEC1-3#” refers to a peptide with CDHR3 residues 20–345; “rEC1-3” is similar except these fragments also have a C345A substitution. (D) Similar to A, the α-His extracted complexes were treated with standard (137 mM) or high (500 mM) NaCl conditions before collection and Western analyses. Each panel (ABCD) is a separate experiment. Binding % is the observed C15 signal pixel count normalized to the recombinant protein (α-His) signal in the panel above (Total Lab 100) relative to positive control (100) in each unit.