1tvd
From Proteopedia
(New page: 200px<br /><applet load="1tvd" size="450" color="white" frame="true" align="right" spinBox="true" caption="1tvd, resolution 1.9Å" /> '''VARIABLE DOMAIN OF T ...) |
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| - | [[Image:1tvd.gif|left|200px]]<br /><applet load="1tvd" size=" | + | [[Image:1tvd.gif|left|200px]]<br /><applet load="1tvd" size="350" color="white" frame="true" align="right" spinBox="true" |
caption="1tvd, resolution 1.9Å" /> | caption="1tvd, resolution 1.9Å" /> | ||
'''VARIABLE DOMAIN OF T CELL RECEPTOR DELTA CHAIN'''<br /> | '''VARIABLE DOMAIN OF T CELL RECEPTOR DELTA CHAIN'''<br /> | ||
==Overview== | ==Overview== | ||
| - | Antigen recognition by T lymphocytes is mediated by cell-surface | + | Antigen recognition by T lymphocytes is mediated by cell-surface glycoproteins known as T-cell antigen receptors (TCRs). These are composed of alpha and beta, or gamma and delta, polypeptide chains with variable (V) and constant (C) regions. In contrast to alphabeta TCRs, which recognize antigen only as peptide fragments bound to molecules of the major histocompatibility complex (MHC), gammadelta TCRs appear to recognize proteins directly, without antigen processing, and to recognize MHC molecules independently of the bound peptide. Moreover, small phosphate-containing non-peptide compounds have also been identified as ligands for certain gammadelta T cells. These studies indicate that antigen recognition by gammadelta TCRs may be fundamentally different from that by alphabeta TCRs. The three-dimensional structures of several alphabeta TCRs and TCR fragments, and their complexes with peptide-MHC or superantigens, have been determined. Here we report the crystal structure of the Vdelta domain of a human gammadelta TCR at 1.9 A resolution. A comparison with antibody and alphabeta TCR V domains reveals that the framework structure of Vdelta more closely resembles that of VH than of Valpha, Vbeta or VL (where H and L refer to heavy and light chains), whereas the relative positions and conformations of its complementarity-determining regions (CDRs) share features of both Valpha and VH. These results provide the first direct evidence that gammadelta TCRs are structurally distinct from alphabeta TCRs and, together with the observation that the CDR3 length distribution of TCR delta chains is similar to that of immunoglobulin heavy chains, are consistent with functional studies suggesting that recognition of certain antigens by gammadelta TCRs may resemble antigen recognition by antibodies. |
==About this Structure== | ==About this Structure== | ||
| - | 1TVD is a [http://en.wikipedia.org/wiki/Single_protein Single protein] structure of sequence from [http://en.wikipedia.org/wiki/Homo_sapiens Homo sapiens]. Full crystallographic information is available from [http:// | + | 1TVD is a [http://en.wikipedia.org/wiki/Single_protein Single protein] structure of sequence from [http://en.wikipedia.org/wiki/Homo_sapiens Homo sapiens]. Full crystallographic information is available from [http://oca.weizmann.ac.il/oca-bin/ocashort?id=1TVD OCA]. |
==Reference== | ==Reference== | ||
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[[Category: Homo sapiens]] | [[Category: Homo sapiens]] | ||
[[Category: Single protein]] | [[Category: Single protein]] | ||
| - | [[Category: Brenner, M | + | [[Category: Brenner, M B.]] |
| - | [[Category: Fields, B | + | [[Category: Fields, B A.]] |
| - | [[Category: Lebedeva, M | + | [[Category: Lebedeva, M I.]] |
| - | [[Category: Li, H | + | [[Category: Li, H M.]] |
| - | [[Category: Llera, A | + | [[Category: Llera, A S.]] |
| - | [[Category: Mariuzza, R | + | [[Category: Mariuzza, R A.]] |
[[Category: delta chain]] | [[Category: delta chain]] | ||
[[Category: immunoreceptor]] | [[Category: immunoreceptor]] | ||
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[[Category: variable domain]] | [[Category: variable domain]] | ||
| - | ''Page seeded by [http:// | + | ''Page seeded by [http://oca.weizmann.ac.il/oca OCA ] on Thu Feb 21 15:17:44 2008'' |
Revision as of 13:17, 21 February 2008
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VARIABLE DOMAIN OF T CELL RECEPTOR DELTA CHAIN
Overview
Antigen recognition by T lymphocytes is mediated by cell-surface glycoproteins known as T-cell antigen receptors (TCRs). These are composed of alpha and beta, or gamma and delta, polypeptide chains with variable (V) and constant (C) regions. In contrast to alphabeta TCRs, which recognize antigen only as peptide fragments bound to molecules of the major histocompatibility complex (MHC), gammadelta TCRs appear to recognize proteins directly, without antigen processing, and to recognize MHC molecules independently of the bound peptide. Moreover, small phosphate-containing non-peptide compounds have also been identified as ligands for certain gammadelta T cells. These studies indicate that antigen recognition by gammadelta TCRs may be fundamentally different from that by alphabeta TCRs. The three-dimensional structures of several alphabeta TCRs and TCR fragments, and their complexes with peptide-MHC or superantigens, have been determined. Here we report the crystal structure of the Vdelta domain of a human gammadelta TCR at 1.9 A resolution. A comparison with antibody and alphabeta TCR V domains reveals that the framework structure of Vdelta more closely resembles that of VH than of Valpha, Vbeta or VL (where H and L refer to heavy and light chains), whereas the relative positions and conformations of its complementarity-determining regions (CDRs) share features of both Valpha and VH. These results provide the first direct evidence that gammadelta TCRs are structurally distinct from alphabeta TCRs and, together with the observation that the CDR3 length distribution of TCR delta chains is similar to that of immunoglobulin heavy chains, are consistent with functional studies suggesting that recognition of certain antigens by gammadelta TCRs may resemble antigen recognition by antibodies.
About this Structure
1TVD is a Single protein structure of sequence from Homo sapiens. Full crystallographic information is available from OCA.
Reference
Structure of the Vdelta domain of a human gammadelta T-cell antigen receptor., Li H, Lebedeva MI, Llera AS, Fields BA, Brenner MB, Mariuzza RA, Nature. 1998 Jan 29;391(6666):502-6. PMID:9461220
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