PMID: 15319492 , Related PDB ids: 1SQ2, 1T6V

Authors:

Stanfield RL, Dooley H, Flajnik MF, Wilson IA

Title:

Crystal structure of a shark single-domain antibody V region in complex with lysozyme.

Journal:

Science. 2004 Sep 17;305(5691):1770-3. Epub 2004 Aug 19.

Abstract:

Cartilaginous fish are the phylogenetically oldest living organisms known to possess components of the vertebrate adaptive immune system. Key to their immune response are heavy-chain, homodimeric immunoglobulins called new antigen receptors (IgNARs), in which the variable (V) domains recognize antigens with only a single immunoglobulin domain, akin to camelid heavy-chain V domains. The 1.45 angstrom resolution crystal structure of the type I IgNAR V domain in complex with hen egg-white lysozyme (HEL) reveals a minimal antigen-binding domain that contains only two of the three conventional complementarity-determining regions but still binds HEL with nanomolar affinity by means of a binding interface comparable in size to conventional antibodies.