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Immunoglobulin. Justas Arasimavi čius. Immunoglobulin. Element of adaptive immune mechanism Better known as antibody It recognize the foreign objects How they work (examples) Animation1 Animation2. Structure of immunoglobulin.
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Immunoglobulin Justas Arasimavičius
Immunoglobulin • Element of adaptive immune mechanism • Better known as antibody • It recognize the foreign objects • How they work (examples) • Animation1 • Animation2
Structure of immunoglobulin • Two identical heavy (H) chains and two identical light (L) chains combine to form this Y-shaped antibody molecule
Disulfide bonds • Bonds between two amino acids result of the SH (sulfhydral) group of one amino acid covalently bonding to the SH group of another amino acid • Stronger than hydrogen bonds • Eg. Hair proteins are held together by disulfide bonds
Heavy chains • The heavy chains each have four domains • Variable domains (VH) • Constant domains (CH1,2,3)
Light chain • The light chains are constructed of two domains • Variable (VL) • Constant (CL)
Structure of immunoglobulin • The fragment antigen binding (Fab fragment) • The fragment crystallizable region (Fc region) • Antibodies bind to antigens by reversible, noncovalent interactions, including hydrogen bonds and charge interactions
How variety is maintained • The variable heavy chain is coded combining 3 genes (VH, DH, JH) • The variable light chain is coded combining 2 genes (VL, JL) • Most likely humans produce between 107 and 109 different shaped Fabs
Antibody Fab region • Antibody (Fab) molecular surface, with the PorA antigen superimposed. • The dark colored groove on the surface of the antibody matches precisely the shape of the PorA antigen • Any changes in the sequence of PorA in this region can disrupt antibody binding http://www.bact.wisc.edu/themicrobialworld/neisseria.html
Structure of immunoglobulin • Functional consequences: • (VH) and (VL) are positioned to stereochemically react with antigen • The stem is good for mediate effector functions
Hinge • Two disulfide bonds in the hinge region unite the two heavy chains • The hinge allows the two antigen-binding Fab regions of each antibody molecule to move
Conclusion • Changes in the antigen binding site conformation are vital for antigen recognition • Herewith the variety of antibody conformation is vital for our health
Reference • http://www.callutheran.edu/Academic_Programs/Departments/BioDev/omm/jmol/ig_div/start.html • http://en.wikipedia.org/ • http://www.path.cam.ac.uk/~mrc7/mikeimages.html • http://www.tulane.edu/~biochem/med/igg.htm • http://www.biology.arizona.edu/IMMUNOLOGY/tutorials/antibody/structure.html • http://student.ccbcmd.edu/courses/bio141/lecguide/unit5/humoral/abystructure/abystructure.html • http://www.mun.ca/biochem/courses/3107/Topics/Antibodies.html • Abul K. Abbas, Andrew H. Lichtman. Basic Immunology Functions and Disorders of the Immune System. Second Edition 2004