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)
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/star
t.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