1cwb
From Proteopedia
(New page: 200px<br /><applet load="1cwb" size="450" color="white" frame="true" align="right" spinBox="true" caption="1cwb, resolution 2.2Å" /> '''THE X-RAY STRUCTURE O...) |
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| - | [[Image:1cwb.gif|left|200px]]<br /><applet load="1cwb" size=" | + | [[Image:1cwb.gif|left|200px]]<br /><applet load="1cwb" size="350" color="white" frame="true" align="right" spinBox="true" |
caption="1cwb, resolution 2.2Å" /> | caption="1cwb, resolution 2.2Å" /> | ||
'''THE X-RAY STRUCTURE OF (MEBM2T)1-CYCLOSPORIN COMPLEXED WITH CYCLOPHILIN A PROVIDES AN EXPLANATION FOR ITS ANOMALOUSLY HIGH IMMUNOSUPPRESSIVE ACTIVITY'''<br /> | '''THE X-RAY STRUCTURE OF (MEBM2T)1-CYCLOSPORIN COMPLEXED WITH CYCLOPHILIN A PROVIDES AN EXPLANATION FOR ITS ANOMALOUSLY HIGH IMMUNOSUPPRESSIVE ACTIVITY'''<br /> | ||
==Overview== | ==Overview== | ||
| - | For most of the cyclosporin A (CsA) analogs, there is generally a good | + | For most of the cyclosporin A (CsA) analogs, there is generally a good correlation between cyclophilin binding and immunosuppression. However, this relationship does not seem to hold for 4-[(E)-2-butenyl]-4,4,N-trimethyl-L-threonine1 (MeBm2t)1-CsA. Its affinity for cyclophilin was reported to be approximately 1% that of CsA and its immunosuppressive activity in vitro was shown to be approximately 30% that of CsA. We report here the crystal structure of a complex between recombinant human cyclophilin A (CypA) and (MeBm2t)1-CsA which has been determined by X-ray crystallography at 2.2 A resolution and refined to an R-factor of 16.3%. (MeBm2t)1-CsA shows a similar bound conformation and network of interactions to CypA as CsA. The measured lower affinity for CypA cannot therefore be explained by a different mode of binding. We propose that the poor affinity to CypA could be accounted for by the existence of an equilibrium in aqueous solution between a 'cyclophilin bound conformation' and a 'non-binding conformation' of (MeBm2t)1-CsA. The relatively high immunosuppressive activity is suggested to result from slight conformational differences observed in the effector domain. |
==About this Structure== | ==About this Structure== | ||
| - | 1CWB 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:// | + | 1CWB 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=1CWB OCA]. |
==Reference== | ==Reference== | ||
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[[Category: Kallen, J.]] | [[Category: Kallen, J.]] | ||
[[Category: Mikol, V.]] | [[Category: Mikol, V.]] | ||
| - | [[Category: Walkinshaw, M | + | [[Category: Walkinshaw, M D.]] |
[[Category: complex (isomerase/immunosuppressant)]] | [[Category: complex (isomerase/immunosuppressant)]] | ||
| - | ''Page seeded by [http:// | + | ''Page seeded by [http://oca.weizmann.ac.il/oca OCA ] on Thu Feb 21 12:10:29 2008'' |
Revision as of 10:10, 21 February 2008
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THE X-RAY STRUCTURE OF (MEBM2T)1-CYCLOSPORIN COMPLEXED WITH CYCLOPHILIN A PROVIDES AN EXPLANATION FOR ITS ANOMALOUSLY HIGH IMMUNOSUPPRESSIVE ACTIVITY
Overview
For most of the cyclosporin A (CsA) analogs, there is generally a good correlation between cyclophilin binding and immunosuppression. However, this relationship does not seem to hold for 4-[(E)-2-butenyl]-4,4,N-trimethyl-L-threonine1 (MeBm2t)1-CsA. Its affinity for cyclophilin was reported to be approximately 1% that of CsA and its immunosuppressive activity in vitro was shown to be approximately 30% that of CsA. We report here the crystal structure of a complex between recombinant human cyclophilin A (CypA) and (MeBm2t)1-CsA which has been determined by X-ray crystallography at 2.2 A resolution and refined to an R-factor of 16.3%. (MeBm2t)1-CsA shows a similar bound conformation and network of interactions to CypA as CsA. The measured lower affinity for CypA cannot therefore be explained by a different mode of binding. We propose that the poor affinity to CypA could be accounted for by the existence of an equilibrium in aqueous solution between a 'cyclophilin bound conformation' and a 'non-binding conformation' of (MeBm2t)1-CsA. The relatively high immunosuppressive activity is suggested to result from slight conformational differences observed in the effector domain.
About this Structure
1CWB is a Single protein structure of sequence from Homo sapiens. Full crystallographic information is available from OCA.
Reference
The X-ray structure of (MeBm2t)1-cyclosporin complexed with cyclophilin A provides an explanation for its anomalously high immunosuppressive activity., Mikol V, Kallen J, Walkinshaw MD, Protein Eng. 1994 May;7(5):597-603. PMID:8073029
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