ABOUT THE MODEL:
This model of an Antibody shows the molecular surface of each chain in the protein. The scale is 10 million times actual size. This means that the molecule is 15.0 nanometers by 10.8 nanometers by 13.3 nanometers but the physical model will be 15.0 centimeters by 10.8 centimeters by 13.3 centimeters. Monochrome, but colored as if Shapeways' "Summer Blue".
ABOUT THE MOLECULE:
Antibodies (also known as immunoglobulins, abbreviated Ig) are gamma globulin proteins that are found in blood or other bodily fluids of vertebrates, and are used by the immune system to identify and neutralize foreign objects, such as bacteria and viruses. They are typically made of basic structural units—each with two large heavy chains and two small light chains—to form, for example, monomers with one unit, dimers with two units or pentamers with five units. Antibodies are produced by a kind of white blood cell called a plasma cell. There are several different types of antibody heavy chains, and several different kinds of antibodies, which are grouped into different isotypes based on which heavy chain they possess. Five different antibody isotypes are known in mammals, which perform different roles, and help direct the appropriate immune response for each different type of foreign object they encounter. Source: http://en.wikipedia.org/wiki/Antibody
ABOUT THE STRUCTURE (1HSG):
PubMed Abstract: The structure of an intact, anti-canine lymphoma monoclonal antibody (Mab231) was determined by molecular replacement and refined in a triclinic cell to an R-value of 20.9%, using synchrotron diffraction data from 2.8 to 20 A resolution. All segments of the antibody, including the hinge region and carbohydrate component, are visible in electron density maps. There is no overall symmetry to the antibody, as the Fc is disposed in an entirely oblique manner with respect to the Fabs. The CH2 and CH3 domains do, however, possess a nearly exact, local 2-fold relationship. The Fab segments are related by a second, independent, local dyad axis, exact only with respect to constant domains. Variable domains exhibit no symmetry relationship as a consequence of the 16 degrees difference in Fab elbow angles. Variable domain pair associations VL:VH for the Fabs are virtually the same, and corresponding CDRs of the two Fabs also are nearly identical in structure. CDR-H3 displays the greatest difference. Hypervariable loops of both Fabs are involved in contacts with symmetry-related Fc segments at the CH2-CH3 switch junction, suggesting a "complex" structure. The hinge segment connecting Fabs with the Fc is quite extended and exhibits thermal factors indicative of a high degree of mobility. It consists of a well-defined upper hinge that partially maintains dyad symmetry and a fairly rigid core bounded above and below by fluid polypeptides that provide segmental flexibility. This structure represents the first visualization by X-ray analysis of a murine Fc segment, and its CH2 domains exhibit substantial rigid body conformational changes with respect to the human Fc used as an initial molecular replacement model. The oligosaccharides were found by difference Fourier syntheses to be very similar to those of the free human Fc fragment, although differences are present in the terminal residues. The detailed structure of the IgG presented here, and the distribution of effector binding sites, appears consistent with effector activation mechanisms involving translocation and/or aggregation of the Fc following antigen binding by the Fabs. Source: http://www.rcsb.org/pdb/explore/explore.do?pdbId=1igt
Amino Acid Sequence, Animals, Antibodies, Monoclonal, Carbohydrate Conformation, Crystallography, X-Ray, Dogs, Immunoglobulin Fab Fragments, Immunoglobulin Fc Fragments, Immunoglobulin G, Immunoglobulin Variable Region, Lymphoma, Mice, Molecular Sequence Data, Protein Structure, Tertiary
Department of Biochemistry, University of California, Riverside 92521, USA.