title: Crystal structure of a camel single-domain VH antibody fragment in complex with lysozyme.
abstract: The Camelidae is the only taxonomic family known to possess functional heavy-chain antibodies, lacking light chains. We report here the 2.5 A resolution crystal structure of a camel VH in complex with its antigen, lysozyme. Compared to human and mouse VH domains, there are no major backbone rearrangements in the VH framework. However, the architecture of the region of VH that interacts with a VL in a conventional FV is different from any previously seen. Moreover, the CDR1 region, although in sequence homologous to human CDR1, deviates fundamentally from the canonical structure. Additionally, one half of the CDR3 contacts the VH region which in conventional immunoglobulins interacts with a VL whereas the other half protrudes from the antigen binding site and penetrates deeply into the active site of lysozyme.
authors.affiliation: Department Ultrastructure, Vlaams Interuniversitair Instituut voor Biotechnologie, Vrije Universiteit, Brussel, Sint Genesius Rode, Belgium.
authors.forename: A
authors.initials: A
authors.lastname: Desmyter
authors.forename: T R
authors.initials: TR
authors.lastname: Transue
authors.forename: M A
authors.initials: MA
authors.lastname: Ghahroudi
authors.forename: M H
authors.initials: MH
authors.lastname: Thi
authors.forename: F
authors.initials: F
authors.lastname: Poortmans
authors.forename: R
authors.initials: R
authors.lastname: Hamers
authors.forename: S
authors.initials: S
authors.lastname: Muyldermans
authors.forename: L
authors.initials: L
authors.lastname: Wyns
mesh_terms: D000595:Amino Acid Sequence; D000818:Animals; D001666:Binding Sites, Antibody; D002162:Camelus / Q000276:immunology*; D018360:Crystallography, X-Ray; D006801:Humans; D007143:Immunoglobulin Heavy Chains / Q000737:chemistry*; D007135:Immunoglobulin Variable Region / Q000737:chemistry*; D051379:Mice; D008969:Molecular Sequence Data; D009113:Muramidase / Q000737:chemistry; D011487:Protein Conformation; D017510:Protein Folding; D011993:Recombinant Fusion Proteins; D016415:Sequence Alignment
chemical_list: D007143:Immunoglobulin Heavy Chains; D007135:Immunoglobulin Variable Region; D011993:Recombinant Fusion Proteins; D009113:Muramidase