Immunoglobulins Flashcards
The 3 most abundant plasma proteins
Antigen
Any foreign molecule bound selectively by antibodies
Immunogen
Molecule (protein, carbohydrate, nucleic acid) that induces antibody production
Antigenic determinant/ epitope
Small region of a larger molecule (like a protein) that elicits the production of a specific antibody
There are __ peptide chains in an antibody
___ holds the 2 heavy chains of an antibody together and a light chain to the heavy chain.
Within the ___ chain there are 3 constant domains and 1 variable domain.
4 peptide chains
Disulfide bonds.
The heavy chain has the 3 constant domains (CH1-CH3) and 1 variable domain (VH); defines the class of immunoglobulin
The light chain can be one of two types
lambda or kappa
Both have constant (CL) and variable (VL) regions
The variable domains from both the heavy and light chains all face to one end of the molecule and serve as
antigen binding sites to the specific epitopes
The five immunoglobulin classes GADEM all have different ___ chains.
Match the chain with teh class.
Which Igs contain multiples of the 2heavychain,2lightchain tetramer?
IgA is a dimer
IgM is a pentamer
The individual constant and variable domains are supersecondary structures.
Describe the Immunoglobulin fold in constant domains vs variable domains
Each domain is composed of B-strands that form anti-parallel B-sheets.
- Constant domains* - 7 strands held together in a 4-3 arrangement by hydrogen bonds or hydrophobic interactions between the R groups.
- Variable domains* - 9 strands held together in a 5-4 arrangement
Complementarity Determining Regions
What are they and where are they?
Area of hypervariable amino sequence that is complementary to the epitope; serve as antigen-binding sites.
In the variable region of antibody light and heavy chains; they’re in the loops that connect the antiparallel B strands (3 loops from light chain, 3 loops from heavy chain)
The combine dvariability of the 12 CDR sites from all 4 peptide chains provides the diversity for
antibody:epitope interactions
The regions between CDRs are called
Framework regions
Steps of an ELISA immunoassay
ELISA shows the quantitation of any protein in a sample
The primary antibody is specific for the protein/antigen of interest.
ChIP
Purpose & steps
- Purpose
- Demosntrates whether specific proteins are associated with specific regions on the genome
- Determines specific locations in the genome where epigenetic modifications occur
- Steps
- Crosslink protein to DNA
- Shear DNA into short pieces
- Use antibodies to immunoprecipitate proteins from the mixture
- Sequence the immunoprecipitated DNA