Contrasting IgG structures reveal extreme asymmetry and flexibility.

The crystal structure of IgG1 b12 represents the first visualization of an intact human IgG with a full-length hinge that has all domains ordered and visible. In comparison to intact murine antibodies and hinge-deletant human antibodies, b12 reveals extreme asymmetry, indicative of the extraordinary interdomain flexibility within an antibody. In addition, the structure provides an illustration of the human IgG1 hinge in its entirety and of asymmetry in the composition of the carbohydrate attached to each C(H)2 domain of the Fc. The two separate hinges assume different conformations in order to accommodate the vastly different placements of the two Fab domains relative to the Fc domain. Interestingly, only one of two possible intra-hinge disulfides is formed.

[1]  D. Davies,et al.  Three-dimensional structure of an intact human immunoglobulin. , 1977, Proceedings of the National Academy of Sciences of the United States of America.

[2]  M. Forster,et al.  Molecular modelling study of HIV p17gag (MA) protein shell utilising data from electron microscopy and X-ray crystallography. , 2000, Journal of molecular biology.

[3]  W. Delano,et al.  Convergent solutions to binding at a protein-protein interface. , 2000, Science.

[4]  R. Dwek,et al.  Mobility and symmetry in the Fc and pFc' fragments as probed by 1H NMR. , 1979, Molecular immunology.

[5]  D. Burton.  Immunoglobulin G: functional sites. , 1985, Molecular immunology.

[6]  J. Kinet,et al.  Structure of the Fc fragment of human IgE bound to its high-affinity receptor FcεRIα , 2000, Nature.

[7]  G. Pauli,et al.  Fine structure of human immunodeficiency virus (HIV) and immunolocalization of structural proteins , 1987 .

[8]  D. R. Davies,et al.  Crystallographic Studies of a Human Immunoglobulin , 1968, Nature.

[9]  Pamela J. Bjorkman,et al.  Crystal structure of the complex of rat neonatal Fc receptor with Fc , 1994, Nature.

[10]  R L Stanfield,et al.  Crystal structures of an antibody to a peptide and its complex with peptide antigen at 2.8 A. , 1992, Science.

[11]  J. Deisenhofer.  Crystallographic refinement and atomic models of a human Fc fragment and its complex with fragment B of protein A from Staphylococcus aureus at 2.9- and 2.8-A resolution. , 1981, Biochemistry.

[12]  A T Brünger,et al.  Direct Observation of Protein Solvation and Discrete Disorder with Experimental Crystallographic Phases , 1996, Science.

[13]  J. Sodroski,et al.  Structure of an HIV gp120 envelope glycoprotein in complex with the CD4 receptor and a neutralizing human antibody , 1998, Nature.

[14]  P. Kraulis.  A program to produce both detailed and schematic plots of protein structures , 1991 .

[15]  Andrew J. Martin,et al.  Structural families in loops of homologous proteins: automatic classification, modelling and application to antibodies. , 1996, Journal of molecular biology.

[16]  L J Harris,et al.  Crystallographic structure of an intact IgG1 monoclonal antibody. , 1998, Journal of molecular biology.

[17]  R. Huber,et al.  Crystallographic structure studies of an IgG molecule and an Fc fragment , 1976, Nature.

[18]  G. Petsko,et al.  Three-dimensional structure of murine anti-p-azophenylarsonate Fab 36-71. 1. X-ray crystallography, site-directed mutagenesis, and modeling of the complex with hapten. , 1991, Biochemistry.

[19]  Haruki Nakamura,et al.  Structural classification of CDR‐H3 in antibodies , 1996, FEBS letters.

[20]  Garrett M. Morris,et al.  Crystal Structure of a Neutralizing Human IgG Against HIV-1: A Template for Vaccine Design , 2001, Science.

[21]  K. R. Ely,et al.  Mobile Fc region in the Zie IgG2 cryoglobulin: comparison of crystals of the F(ab')2 fragment and the intact immunoglobulin. , 1978, Biochemistry.

[22]  G J Kleywegt,et al.  Crystal structure of the C2 fragment of streptococcal protein G in complex with the Fc domain of human IgG. , 1995, Structure.

[23]  G R Pilkington,et al.  Molecular profile of an antibody response to HIV-1 as probed by combinatorial libraries. , 1993, Journal of molecular biology.

[24]  A. Lesk,et al.  Standard conformations for the canonical structures of immunoglobulins. , 1997, Journal of molecular biology.

[25]  R M Esnouf,et al.  Further additions to MolScript version 1.4, including reading and contouring of electron-density maps. , 1999, Acta crystallographica. Section D, Biological crystallography.

[26]  B. Golinelli‐Pimpaneau,et al.  Crystal structure of the complex of a catalytic antibody Fab fragment with a transition state analog: structural similarities in esterase-like catalytic antibodies. , 1995, Proceedings of the National Academy of Sciences of the United States of America.

[27]  D R Burton,et al.  Efficient neutralization of primary isolates of HIV-1 by a recombinant human monoclonal antibody. , 1994, Science.

[28]  D. Kaslow,et al.  Crystallization of an intact monoclonal antibody (4B7) against Plasmodium falciparum malaria with peptides from the Pfs25 protein antigen. , 1994, Acta crystallographica. Section D, Biological crystallography.

[29]  E. Padlan,et al.  X-ray crystallography of antibodies. , 1996, Advances in protein chemistry.

[30]  R. Dwek,et al.  A rapid high-resolution high-performance liquid chromatographic method for separating glycan mixtures and analyzing oligosaccharide profiles. , 1996, Analytical biochemistry.

[31]  R. Dwek,et al.  Glycosylation: heterogeneity and the 3D structure of proteins. , 1997, Critical reviews in biochemistry and molecular biology.

[32]  L. Presta,et al.  X-ray structures of the antigen-binding domains from three variants of humanized anti-p185HER2 antibody 4D5 and comparison with molecular modeling. , 1993, Journal of molecular biology.

[33]  J L Sussman,et al.  Specific chemical and structural damage to proteins produced by synchrotron radiation. , 2000, Proceedings of the National Academy of Sciences of the United States of America.

[34]  Robert Huber,et al.  The 3.2-Å crystal structure of the human IgG1 Fc fragment–FcγRIII complex , 2000, Nature.

[35]  D. Davies,et al.  Expression of biological effector functions by immunoglobulin G molecules lacking the hinge region. , 1981, Proceedings of the National Academy of Sciences of the United States of America.

[36]  R L Stanfield,et al.  Crystal structure of a human immunodeficiency virus type 1 neutralizing antibody, 50.1, in complex with its V3 loop peptide antigen. , 1993, Proceedings of the National Academy of Sciences of the United States of America.

[37]  E. Kabat,et al.  Sequences of proteins of immunological interest , 1991 .

[38]  A. Edmundson,et al.  Three-dimensional structure of a human immunoglobulin with a hinge deletion. , 1993, Proceedings of the National Academy of Sciences of the United States of America.

[39]  N. Green,et al.  Electron microscopy of an antibody-hapten complex. , 1967, Journal of molecular biology.

[40]  S. Larson,et al.  Characterization of crystals of an intact monoclonal antibody for canine lymphoma. , 1991, Journal of molecular biology.

[41]  D. Burton,et al.  Antibody: the flexible adaptor molecule. , 1990, Trends in biochemical sciences.

[42]  J Deisenhofer,et al.  Crystallographic refinement and atomic models of the intact immunoglobulin molecule Kol and its antigen-binding fragment at 3.0 A and 1.0 A resolution. , 1980, Journal of molecular biology.

[43]  A. McPherson,et al.  Chimeric human-simian anti-CD4 antibodies form crystalline high symmetry particles. , 2000, Journal of structural biology.

[44]  I. Shimada,et al.  Pairing of oligosaccharides in the Fc region of immunoglobulin G , 2000, FEBS letters.

[45]  W. Burmeister,et al.  Structural changes in a cryo-cooled protein crystal owing to radiation damage. , 2000, Acta crystallographica. Section D, Biological crystallography.

[46]  J Deisenhofer,et al.  Structure of the human antibody molecule Kol (immunoglobulin G1): an electron density map at 5 A resolution. , 1976, Journal of molecular biology.

[47]  L. J. Harris,et al.  Refined structure of an intact IgG2a monoclonal antibody. , 1997, Biochemistry.

[48]  K. R. Ely,et al.  Three-dimensional structure of the Mcg IgG1 immunoglobulin. , 1983, Molecular immunology.

[49]  L. J. Harris,et al.  Crystallization of intact monoclonal antibodies , 1995, Proteins.

[50]  Alexander McPherson,et al.  The three-dimensional structure of an intact monoclonal antibody for canine lymphoma , 1992, Nature.

[51]  T. T. Wu,et al.  Length distribution of CDRH3 in antibodies , 1993, Proteins.

[52]  M. Taussig,et al.  Structure of human IgM rheumatoid factor Fab bound to its autoantigen IgG Fc reveals a novel topology of antibody—antigen interaction , 1997, Nature Structural Biology.

[53]  M. Steward,et al.  Structure and function of antibodies , 1977 .

[54]  C. Barbas,et al.  Crystallization and preliminary structure determination of an intact human immunoglobulin, b12: an antibody that broadly neutralizes primary isolates of HIV-1. , 2001, Acta crystallographica. Section D, Biological crystallography.