1e5a: Difference between revisions
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==Overview== | ==Overview== | ||
The binding of two organohalogen substances, pentabromophenol (PBP) and, 2,4,6-tribromophenol (TBP), to human transthyretin (TTR), a thyroid, hormone transport protein, has been studied by in vitro competitive, binding assays and by X-ray crystallography. Both compounds bind to TTR, with high affinity, in competition with the natural ligand thyroxine, (T(4)). The crystal structures of the TTR-PBP and TTR-TBP complexes show, some unusual binding patterns for the ligands. They bind exclusively in, the 'reversed' mode, with their hydroxyl group pointing towards the mouth, of the binding channel and in planes approximately perpendicular to that, adopted by the T(4) phenolic ring in a TTR-T(4) complex, a feature not, observed before. The hydroxyl group in the ligands, which was previously, ... | The binding of two organohalogen substances, pentabromophenol (PBP) and, 2,4,6-tribromophenol (TBP), to human transthyretin (TTR), a thyroid, hormone transport protein, has been studied by in vitro competitive, binding assays and by X-ray crystallography. Both compounds bind to TTR, with high affinity, in competition with the natural ligand thyroxine, (T(4)). The crystal structures of the TTR-PBP and TTR-TBP complexes show, some unusual binding patterns for the ligands. They bind exclusively in, the 'reversed' mode, with their hydroxyl group pointing towards the mouth, of the binding channel and in planes approximately perpendicular to that, adopted by the T(4) phenolic ring in a TTR-T(4) complex, a feature not, observed before. The hydroxyl group in the ligands, which was previously, thought to be a key ingredient for a strong binding to TTR, does not seem, to play an important role in the binding of these compounds to TTR. In the, TTR-PBP complex, it is primarily the halogens which interact with the TTR, molecule and therefore must account for the strong affinity of binding., The interactions with the halogens are smaller in number in TTR-TBP and, there is a decrease in affinity, even though the interaction with the, hydroxyl group is stronger than that in the TTR-PBP complex. | ||
==About this Structure== | ==About this Structure== | ||
1E5A is a | 1E5A is a [http://en.wikipedia.org/wiki/Single_protein Single protein] structure of sequence from [http://en.wikipedia.org/wiki/Homo_sapiens Homo sapiens] with TBP as [http://en.wikipedia.org/wiki/ligand ligand]. Structure known Active Sites: 1 and 2. Full crystallographic information is available from [http://ispc.weizmann.ac.il/oca-bin/ocashort?id=1E5A OCA]. | ||
==Reference== | ==Reference== | ||
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[[Category: transport(thyroxine)]] | [[Category: transport(thyroxine)]] | ||
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Revision as of 13:44, 5 November 2007
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STRUCTURE OF HUMAN TRANSTHYRETIN COMPLEXED WITH BROMOPHENOLS: A NEW MODE OF BINDING
OverviewOverview
The binding of two organohalogen substances, pentabromophenol (PBP) and, 2,4,6-tribromophenol (TBP), to human transthyretin (TTR), a thyroid, hormone transport protein, has been studied by in vitro competitive, binding assays and by X-ray crystallography. Both compounds bind to TTR, with high affinity, in competition with the natural ligand thyroxine, (T(4)). The crystal structures of the TTR-PBP and TTR-TBP complexes show, some unusual binding patterns for the ligands. They bind exclusively in, the 'reversed' mode, with their hydroxyl group pointing towards the mouth, of the binding channel and in planes approximately perpendicular to that, adopted by the T(4) phenolic ring in a TTR-T(4) complex, a feature not, observed before. The hydroxyl group in the ligands, which was previously, thought to be a key ingredient for a strong binding to TTR, does not seem, to play an important role in the binding of these compounds to TTR. In the, TTR-PBP complex, it is primarily the halogens which interact with the TTR, molecule and therefore must account for the strong affinity of binding., The interactions with the halogens are smaller in number in TTR-TBP and, there is a decrease in affinity, even though the interaction with the, hydroxyl group is stronger than that in the TTR-PBP complex.
About this StructureAbout this Structure
1E5A is a Single protein structure of sequence from Homo sapiens with TBP as ligand. Structure known Active Sites: 1 and 2. Full crystallographic information is available from OCA.
ReferenceReference
Structure of human transthyretin complexed with bromophenols: a new mode of binding., Ghosh M, Meerts IA, Cook A, Bergman A, Brouwer A, Johnson LN, Acta Crystallogr D Biol Crystallogr. 2000 Sep;56(Pt 9):1085-95. PMID:10957627
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