Crystal structures of immunoglobulin Fc heterodimers reveal the molecular basis for heterodimer formation.
We determined the X-ray crystal structure of an immunoglobulin fragment crystallizable (Fc) heterodimer, EW-RVT, at a resolution of 2.5Å and found that the designed asymmetric interaction residues located in the heterodimeric CH3 interface favor Fc heterodimer formation. We further generated an inter-CH3 disulfide-bonded heterodimeric Fc variant, EW-RVT(S-S), which exhibited improved heterodimer formation and thermodynamic stability compared with the parent EW-RVT variant. The crystal structure of EW-RVTS-S superimposed very closely with the wild-type Fc structure. Our results provide the detailed structure of heterodimeric Fc scaffolds, which will be useful for the generation of immunoglobulin G (IgG)-like bispecific antibodies.
Department of Molecular Science and Technology, Ajou University, Suwon 443-749, Republic of Korea.
Hye-Ji
HJ
Choi
Department of Molecular Science and Technology, Ajou University, Suwon 443-749, Republic of Korea; College of Pharmacy, Ajou University, Suwon 443-749, Republic of Korea.
Seung-Hyeon
SH
Seok
Department of Molecular Science and Technology, Ajou University, Suwon 443-749, Republic of Korea.
Ye-Jin
YJ
Kim
Department of Molecular Science and Technology, Ajou University, Suwon 443-749, Republic of Korea; College of Pharmacy, Ajou University, Suwon 443-749, Republic of Korea.
Min-Duk
MD
Seo
Department of Molecular Science and Technology, Ajou University, Suwon 443-749, Republic of Korea. Electronic address: kimys@ajou.ac.kr.
Yong-Sung
YS
Kim
D018360:Crystallography, X-Ray; D006801:Humans; D007141:Immunoglobulin Fc Fragments / Q000737:chemistry*; D007074:Immunoglobulin G / Q000737:chemistry*; D055503:Protein Multimerization; D055550:Protein Stability; D020836:Protein Structure, Quaternary; D013329:Structure-Activity Relationship
D007141:Immunoglobulin Fc Fragments; D007074:Immunoglobulin G
Asymmetric disulfide bonds; Bispecific antibody; CH3 domain interface; Fc engineering; Immunoglobulin Fc heterodimer; Thermal stability