Patent ID: 8216805

Claim:
A method of preparing a heteromultimer comprising a first polypeptide and a second polypeptide each comprising a C H 3 antibody constant domain, wherein said polypeptides meet at an engineered interface within the C H 3 domain, the method comprising the steps of: (a) creating an engineered protuberance in the interface of the first polypeptide by replacing at least one contact residue of said polypeptide within its C H 3 domain; (b) creating, an engineered cavity in the interface of the second polypeptide by replacing at least one contact residue of said polypeptide within its C H 3 domain, wherein said protuberance in the first polypeptide is positional in said cavity of the second polypeptide so as to form a protuberance-into-cavity mutant pair, and wherein the contact residue to be replaced on the first polypeptide corresponds to an IgG residue selected from the group consisting of amino acid residues 347, 349, 350, 351, 366, 368, 370, 392, 394, 395, 397, 398, 399, 405, 407 and 409, according to the amino acid numbering as shown in FIG. 5 ; (c) expressing said first and second polypeptides in a host cell to obtain the heteromultimer; (d) recovering the heteromultimer from the host cell culture; wherein said creating an engineered protuberance comprises replacing the nucleic acid encoding the original residue with nucleic acid encoding an import residue having a larger side chain volume than the original residue; and wherein said creating an engineered cavity comprises replacing the nucleic acid encoding an original residue with nucleic acid encoding an import residue having a smaller side chain volume than the original residue.