Crystal structure of murine sCEACAM1a[1,4]: a coronavirus receptor in the CEA family

• Published in: The EMBO journal 2002-05, Vol.21 (9), p.2076-2086
• Main Authors: Tan, Kemin, Zelus, Bruce D., Meijers, Rob, Liu, Jin-huan, Bergelson, Jeffrey M., Duke, Norma, Zhang, Rongguang, Joachimiak, Andrzej, Holmes, Kathryn V., Wang, Jia-huai
• Format: Article
• Language: English
• Subjects: Amino Acid Sequence; Animals; Antigens, CD; bacterial binding; carcinoembryonic antigen; Carcinoembryonic Antigen - chemistry; CEA family; CEACAM1 protein; cell adhesion; Cell Adhesion Molecules; Conserved Sequence; Coronavirus; Coronavirus - chemistry; Coronavirus - physiology; coronavirus receptor; crystal structure; Crystallography, X-Ray; EMBO23; EMBO40; Glycoproteins - chemistry; Mice; Molecular Sequence Data; Multigene Family; Murine hepatitis virus; Protein Binding - physiology; Protein Isoforms - chemistry; Protein Structure, Tertiary; Receptors, Coronavirus; Receptors, Virus - chemistry; Sequence Alignment
• ISSN: 0261-4189; 1460-2075; 1460-2075
• DOI: 10.1093/emboj/21.9.2076

CEACAM1 is a member of the carcinoembryonic antigen (CEA) family. Isoforms of murine CEACAM1 serve as receptors for mouse hepatitis virus (MHV), a murine coronavirus. Here we report the crystal structure of soluble murine sCEACAM1a[1,4], which is composed of two Ig‐like domains and has MHV neutralizing activity. Its N‐terminal domain has a uniquely folded CC′ loop that encompasses key virus‐binding residues. This is the first atomic structure of any member of the CEA family, and provides a prototypic architecture for functional exploration of CEA family members. We discuss the structural basis of virus receptor activities of murine CEACAM1 proteins, binding of Neisseria to human CEACAM1, and other homophilic and heterophilic interactions of CEA family members.