1kjm
From Proteopedia
(New page: 200px<br /><applet load="1kjm" size="450" color="white" frame="true" align="right" spinBox="true" caption="1kjm, resolution 2.35Å" /> '''TAP-A-associated rat...) |
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| - | [[Image:1kjm.jpg|left|200px]]<br /><applet load="1kjm" size=" | + | [[Image:1kjm.jpg|left|200px]]<br /><applet load="1kjm" size="350" color="white" frame="true" align="right" spinBox="true" |
caption="1kjm, resolution 2.35Å" /> | caption="1kjm, resolution 2.35Å" /> | ||
'''TAP-A-associated rat MHC class I molecule'''<br /> | '''TAP-A-associated rat MHC class I molecule'''<br /> | ||
==Overview== | ==Overview== | ||
| - | Antigenic peptides are loaded onto class I MHC molecules in the | + | Antigenic peptides are loaded onto class I MHC molecules in the endoplasmic reticulum (ER) by a complex consisting of the MHC class I heavy chain, beta(2)-microglobulin, calreticulin, tapasin, Erp57 (ER60) and the transporter associated with antigen processing (TAP). While most mammalian species transport these peptides into the ER via a single allele of TAP, rats have evolved different TAPs, TAP-A and TAP-B, that are present in different inbred strains. Each TAP delivers a different spectrum of peptides and is associated genetically with distinct subsets of MHC class Ia alleles, but the molecular basis for the conservation (or co-evolution) of the two transporter alleles is unknown. We have determined the crystal structures of a representative of each MHC subset, viz RT1-A(a) and RT1-A1(c), in association with high-affinity nonamer peptides. The structures reveal how the chemical properties of the two different rat MHC F-pockets match those of the corresponding C termini of the peptides, corroborating biochemical data on the rates of peptide-MHC complex assembly. An unusual sequence in RT1-A1(c) leads to a major deviation from the highly conserved beta(3)/alpha(1) loop (residues 40-59) conformation in mouse and human MHC class I structures. This loop change contributes to profound changes in the shape of the A-pocket in the peptide-binding groove and may explain the function of RT1-A1(c) as an inhibitory natural killer cell ligand. |
==About this Structure== | ==About this Structure== | ||
| - | 1KJM is a [http://en.wikipedia.org/wiki/Protein_complex Protein complex] structure of sequences from [http://en.wikipedia.org/wiki/Rattus_norvegicus Rattus norvegicus] with SO4 as [http://en.wikipedia.org/wiki/ligand ligand]. Full crystallographic information is available from [http:// | + | 1KJM is a [http://en.wikipedia.org/wiki/Protein_complex Protein complex] structure of sequences from [http://en.wikipedia.org/wiki/Rattus_norvegicus Rattus norvegicus] with <scene name='pdbligand=SO4:'>SO4</scene> as [http://en.wikipedia.org/wiki/ligand ligand]. Full crystallographic information is available from [http://oca.weizmann.ac.il/oca-bin/ocashort?id=1KJM OCA]. |
==Reference== | ==Reference== | ||
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[[Category: Protein complex]] | [[Category: Protein complex]] | ||
[[Category: Rattus norvegicus]] | [[Category: Rattus norvegicus]] | ||
| - | [[Category: Butcher, G | + | [[Category: Butcher, G W.]] |
[[Category: Joly, E.]] | [[Category: Joly, E.]] | ||
| - | [[Category: Rudolph, M | + | [[Category: Rudolph, M G.]] |
| - | [[Category: Speir, J | + | [[Category: Speir, J A.]] |
[[Category: Stevens, J.]] | [[Category: Stevens, J.]] | ||
[[Category: Trowsdale, J.]] | [[Category: Trowsdale, J.]] | ||
| - | [[Category: Wilson, I | + | [[Category: Wilson, I A.]] |
[[Category: SO4]] | [[Category: SO4]] | ||
[[Category: extracellular domain]] | [[Category: extracellular domain]] | ||
| Line 25: | Line 25: | ||
[[Category: peptide-mhc complex]] | [[Category: peptide-mhc complex]] | ||
| - | ''Page seeded by [http:// | + | ''Page seeded by [http://oca.weizmann.ac.il/oca OCA ] on Thu Feb 21 13:34:51 2008'' |
Revision as of 11:34, 21 February 2008
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TAP-A-associated rat MHC class I molecule
Overview
Antigenic peptides are loaded onto class I MHC molecules in the endoplasmic reticulum (ER) by a complex consisting of the MHC class I heavy chain, beta(2)-microglobulin, calreticulin, tapasin, Erp57 (ER60) and the transporter associated with antigen processing (TAP). While most mammalian species transport these peptides into the ER via a single allele of TAP, rats have evolved different TAPs, TAP-A and TAP-B, that are present in different inbred strains. Each TAP delivers a different spectrum of peptides and is associated genetically with distinct subsets of MHC class Ia alleles, but the molecular basis for the conservation (or co-evolution) of the two transporter alleles is unknown. We have determined the crystal structures of a representative of each MHC subset, viz RT1-A(a) and RT1-A1(c), in association with high-affinity nonamer peptides. The structures reveal how the chemical properties of the two different rat MHC F-pockets match those of the corresponding C termini of the peptides, corroborating biochemical data on the rates of peptide-MHC complex assembly. An unusual sequence in RT1-A1(c) leads to a major deviation from the highly conserved beta(3)/alpha(1) loop (residues 40-59) conformation in mouse and human MHC class I structures. This loop change contributes to profound changes in the shape of the A-pocket in the peptide-binding groove and may explain the function of RT1-A1(c) as an inhibitory natural killer cell ligand.
About this Structure
1KJM is a Protein complex structure of sequences from Rattus norvegicus with as ligand. Full crystallographic information is available from OCA.
Reference
Crystal structures of two rat MHC class Ia (RT1-A) molecules that are associated differentially with peptide transporter alleles TAP-A and TAP-B., Rudolph MG, Stevens J, Speir JA, Trowsdale J, Butcher GW, Joly E, Wilson IA, J Mol Biol. 2002 Dec 13;324(5):975-90. PMID:12470953
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