Download Immunoglobulin

Immunoglobulin
Justas Arasimavičius
Immunoglobulin
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Element of adaptive immune mechanism
Better known as antibody
It recognize the foreign objects
How they work (examples)
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Animation1
Animation2
Structure of immunoglobulin
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Two identical
heavy (H) chains
and two identical
light (L) chains
combine to form
this Y-shaped
antibody molecule
Disulfide bonds
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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
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The heavy chains
each have four
domains
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Variable domains
(VH)
Constant domains
(CH1,2,3)
Light chain
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The light chains
are constructed of
two domains
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Variable (VL)
Constant (CL)
Structure of immunoglobulin
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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
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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
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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
Antigen binding some pictures
Antigen binding some pictures
Structure of immunoglobulin
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Functional
consequences:
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(VH) and (VL) are
positioned to
stereochemically
react with antigen
The stem is good
for mediate
effector functions
Hinge
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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
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Changes in the antigen binding site
conformation are vital for antigen
recognition
Herewith the variety of antibody
conformation is vital for our health
Reference
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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