1ict
From Proteopedia
(New page: 200px<br /> <applet load="1ict" size="450" color="white" frame="true" align="right" spinBox="true" caption="1ict, resolution 3.00Å" /> '''MONOCLINIC FORM OF ...) |
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caption="1ict, resolution 3.00Å" /> | caption="1ict, resolution 3.00Å" /> | ||
'''MONOCLINIC FORM OF HUMAN TRANSTHYRETIN COMPLEXED WITH THYROXINE (T4)'''<br /> | '''MONOCLINIC FORM OF HUMAN TRANSTHYRETIN COMPLEXED WITH THYROXINE (T4)'''<br /> | ||
==Overview== | ==Overview== | ||
| - | The crystal structure of a new polymorphic form of human transthyretin | + | The crystal structure of a new polymorphic form of human transthyretin (hTTR) with a lattice containing a unique assembly of apo hTTR and TTR-T(4) complex has been determined to 3 A resolution. The monoclinic form of human TTR reported here crystallizes in space group P2(1), with unit-cell parameters a = 76.7 (6), b = 96.7 (8), c = 81.7 (4) A, beta = 106.8 (4) degrees. The asymmetric unit contains two tetramers of transthyretin related by the non-crystallographic symmetry (NCS) operation of a 90.28 degrees rotation between two hTTR molecules around an axis close to crystallographic z. The r.m.s. difference between the two tetramers calculated from their C(alpha) positions is 0.48 A. The structure was refined using 15.0-3.0 A resolution data to R = 22.9% and R(free) = 28.9% for reflections F > 0.0sigma(F), and R = 19.7% and R(free) = 25.8% for reflections F > 3.0sigma(F). The intermolecular interactions involve the tips of alpha-helices and loops around Arg21, Glu61 and Ser100 of all monomers. The electron-density maps revealed residual thyroxine (T(4)) bound in only one of the two unique tetrameric TTR molecules, with an occupancy of 53%, while the second tetramer is unliganded. One thyroxine ligand is bound in a way similar to the orientations described for the orthorhombic form of the hTTR-T(4) complex. The T(4) bound in the second site is positioned similar to 3',5'-dinitro-N-acetyl-L-thyronine in its hTTR complex. Differences in the size of the central channel defined by the D, A, G and H beta-strands of two monomeric subunits are observed between the apo TTR and T(4)-bound tetramer. The averaged distances between Ala108 C(alpha) and its equivalent measured across each binding site are 12.34 A for the T(4)-bound and 10.96 A for the unliganded TTR tetramer, respectively. The observed differences might reflect the mechanics of the ligand binding in the channel and possibly explain the observed negative cooperativity effect for ligand binding. |
==Disease== | ==Disease== | ||
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==About this Structure== | ==About this Structure== | ||
| - | 1ICT 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 T44 as [http://en.wikipedia.org/wiki/ligand ligand]. Full crystallographic information is available from [http:// | + | 1ICT 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 <scene name='pdbligand=T44:'>T44</scene> as [http://en.wikipedia.org/wiki/ligand ligand]. Full crystallographic information is available from [http://oca.weizmann.ac.il/oca-bin/ocashort?id=1ICT OCA]. |
==Reference== | ==Reference== | ||
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[[Category: transport]] | [[Category: transport]] | ||
| - | ''Page seeded by [http:// | + | ''Page seeded by [http://oca.weizmann.ac.il/oca OCA ] on Thu Feb 21 13:10:27 2008'' |
Revision as of 11:10, 21 February 2008
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MONOCLINIC FORM OF HUMAN TRANSTHYRETIN COMPLEXED WITH THYROXINE (T4)
Contents |
Overview
The crystal structure of a new polymorphic form of human transthyretin (hTTR) with a lattice containing a unique assembly of apo hTTR and TTR-T(4) complex has been determined to 3 A resolution. The monoclinic form of human TTR reported here crystallizes in space group P2(1), with unit-cell parameters a = 76.7 (6), b = 96.7 (8), c = 81.7 (4) A, beta = 106.8 (4) degrees. The asymmetric unit contains two tetramers of transthyretin related by the non-crystallographic symmetry (NCS) operation of a 90.28 degrees rotation between two hTTR molecules around an axis close to crystallographic z. The r.m.s. difference between the two tetramers calculated from their C(alpha) positions is 0.48 A. The structure was refined using 15.0-3.0 A resolution data to R = 22.9% and R(free) = 28.9% for reflections F > 0.0sigma(F), and R = 19.7% and R(free) = 25.8% for reflections F > 3.0sigma(F). The intermolecular interactions involve the tips of alpha-helices and loops around Arg21, Glu61 and Ser100 of all monomers. The electron-density maps revealed residual thyroxine (T(4)) bound in only one of the two unique tetrameric TTR molecules, with an occupancy of 53%, while the second tetramer is unliganded. One thyroxine ligand is bound in a way similar to the orientations described for the orthorhombic form of the hTTR-T(4) complex. The T(4) bound in the second site is positioned similar to 3',5'-dinitro-N-acetyl-L-thyronine in its hTTR complex. Differences in the size of the central channel defined by the D, A, G and H beta-strands of two monomeric subunits are observed between the apo TTR and T(4)-bound tetramer. The averaged distances between Ala108 C(alpha) and its equivalent measured across each binding site are 12.34 A for the T(4)-bound and 10.96 A for the unliganded TTR tetramer, respectively. The observed differences might reflect the mechanics of the ligand binding in the channel and possibly explain the observed negative cooperativity effect for ligand binding.
Disease
Known diseases associated with this structure: Amyloid neuropathy, familial, several allelic types OMIM:[176300], Amyloidosis, senile systemic OMIM:[176300], Carpal tunnel syndrome, familial OMIM:[176300], Dystransthyretinemic hyperthyroxinemia OMIM:[176300]
About this Structure
1ICT is a Single protein structure of sequence from Homo sapiens with as ligand. Full crystallographic information is available from OCA.
Reference
Structure of a new polymorphic monoclinic form of human transthyretin at 3 A resolution reveals a mixed complex between unliganded and T4-bound tetramers of TTR., Wojtczak A, Neumann P, Cody V, Acta Crystallogr D Biol Crystallogr. 2001 Jul;57(Pt 7):957-67. Epub 2001, Jun 21. PMID:11418763
Page seeded by OCA on Thu Feb 21 13:10:27 2008
Categories: Homo sapiens | Single protein | Cody, V. | Neumann, P. | Wojtczak, A. | T44 | Albumin | Amyloid | Greek key beta barrel | Liver | Plasma | Polyneuropathy | Prealbumin | Thyroid hormone | Thyroxine | Transport
