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21 Cards in this Set
- Front
- Back
Class I molecules |
Consist of two noncovalently linked polypeptide chains |
|
MHC-encoded 44-47 kD α chain (heavychain) Non-MHC encoded 12 kDa subunit called β2-microgIobuIin |
Chains of Class I molecules |
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5 domains 3 extracellular domains (a1-a3) transmembrane domain cytoplasmic domain |
α chain consists of |
|
Peptide binding cleft |
Produced by interaction of α1 and α2 |
|
α3 |
Conserved Ig domain |
|
β2-microglobulin |
consists of a single domain and serves to stabilize the structure |
|
a3 |
Binding site for CD8+ |
|
Class 1 molecule |
A heterotrimer consisting of: An α chain, β2-microglobulin, a bound antigenic peptide |
|
Class I MHC molecules |
only useful peptide-loaded MHC molecules are expressed on cell surfaces. |
|
Class II MHC molecules |
Composed of two noncovalently associated polypeptide chains:32 to 34 kDa α chain29 to 32 kDa β chain |
|
Class II MHC molecules |
Composed of 32 to 34 kDa α chain 29 to 32 kDa β chain |
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TRUE |
The genes encoding both chains of class II molecules are polymorphic |
|
Peptide binding cleft |
Interaction of α1 and β1
|
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α2 and β2 |
Folded into Ig domain Nonpolymorphic |
|
β2 |
Site for CD4+ attachment |
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Class II MHC Molecules |
A heterotrimer consisting: α heavy chains, β heavy chains a bound antigenic peptide |
|
TRUE |
Each class I or class II MHC molecule has a single peptide-binding cleft that binds one peptide at a time, but each MHC molecule can bind many different peptides. |
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TRUE |
The peptides that bind to MHC molecules share structural features that promote this interaction. |
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true |
The association of antigenic peptides and MHC molecules is a saturable interaction with a very slow off-rate. |
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True |
MHC molecules cannot discriminate foreign peptides and self-derived peptides |
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noncovalent |
The binding of peptides to MHC molecules is a ____________ interaction mediated by residues both in the peptides and in the clefts of the MHC molecules |