title: Crystal structure of a human single domain antibody dimer formed through V(H)-V(H) non-covalent interactions.
abstract: Single-domain antibodies (sdAbs) derived from human V(H) are considered to be less soluble and prone to aggregate which makes it difficult to determine the crystal structures. In this study, we isolated and characterized two anti-human epidermal growth factor receptor-2 (HER2) sdAbs, Gr3 and Gr6, from a synthetic human V(H) phage display library. Size exclusion chromatography and surface plasmon resonance analyses demonstrated that Gr3 is a monomer, but that Gr6 is a strict dimer. To understand this different molecular behavior, we solved the crystal structure of Gr6 to 1.6 Å resolution. The crystal structure revealed that the homodimer assembly of Gr6 closely mimics the V(H)-V(L) heterodimer of immunoglobulin variable domains and the dimerization interface is dominated by hydrophobic interactions.
authors.affiliation: Institute for Biological Sciences, National Research Council Canada, Ottawa, Ontario, Canada.
authors.forename: Toya Nath
authors.initials: TN
authors.lastname: Baral
authors.forename: Shi-Yu
authors.initials: SY
authors.lastname: Chao
authors.forename: Shenghua
authors.initials: S
authors.lastname: Li
authors.forename: Jamshid
authors.initials: J
authors.lastname: Tanha
authors.forename: Mehdi
authors.initials: M
authors.lastname: Arbabi-Ghahroudi
authors.forename: Jianbing
authors.initials: J
authors.lastname: Zhang
authors.forename: Shuying
authors.initials: S
authors.lastname: Wang
mesh_terms: D000595:Amino Acid Sequence; D000906:Antibodies / Q000737:chemistry* / Q000276:immunology; D000918:Antibody Specificity / Q000276:immunology; D018360:Crystallography, X-Ray; D006801:Humans; D057927:Hydrophobic and Hydrophilic Interactions; D007135:Immunoglobulin Variable Region / Q000737:chemistry* / Q000378:metabolism*; D008958:Models, Molecular; D008969:Molecular Sequence Data; D011485:Protein Binding / Q000276:immunology; D055503:Protein Multimerization / Q000276:immunology*; D017433:Protein Structure, Secondary; D017434:Protein Structure, Tertiary; D018719:Erb-b2 Receptor Tyrosine Kinases / Q000276:immunology; D012996:Solutions; D044366:Transition Temperature
chemical_list: D000906:Antibodies; D007135:Immunoglobulin Variable Region; D018719:Erb-b2 Receptor Tyrosine Kinases; D012996:Solutions; C508053:ERBB2 protein, human