1qab: Difference between revisions
New page: left|200px<br /><applet load="1qab" size="450" color="white" frame="true" align="right" spinBox="true" caption="1qab, resolution 3.20Å" /> '''The structure of hum... |
No edit summary |
||
| Line 1: | Line 1: | ||
[[Image:1qab.gif|left|200px]]<br /><applet load="1qab" size=" | [[Image:1qab.gif|left|200px]]<br /><applet load="1qab" size="350" color="white" frame="true" align="right" spinBox="true" | ||
caption="1qab, resolution 3.20Å" /> | caption="1qab, resolution 3.20Å" /> | ||
'''The structure of human retinol binding protein with its carrier protein transthyretin reveals interaction with the carboxy terminus of RBP'''<br /> | '''The structure of human retinol binding protein with its carrier protein transthyretin reveals interaction with the carboxy terminus of RBP'''<br /> | ||
==Overview== | ==Overview== | ||
Whether ultimately utilized as retinoic acid, retinal, or retinol, vitamin | Whether ultimately utilized as retinoic acid, retinal, or retinol, vitamin A is transported to the target cells as all-trans-retinol bound to retinol-binding protein (RBP). Circulating in the plasma, RBP itself is bound to transthyretin (TTR, previously referred to as thyroxine-binding prealbumin). In vitro one tetramer of TTR can bind two molecules of retinol-binding protein. However, the concentration of RBP in the plasma is limiting, and the complex isolated from serum is composed of TTR and RBP in a 1 to 1 stoichiometry. We report here the crystallographic structure at 3.2 A of the protein-protein complex of human RBP and TTR. RBP binds at a 2-fold axis of symmetry in the TTR tetramer, and consequently the recognition site itself has 2-fold symmetry: Four TTR amino acids (Arg-21, Val-20, Leu-82, and Ile-84) are contributed by two monomers. Amino acids Trp-67, Phe-96, and Leu-63 and -97 from RBP are flanked by the symmetry-related side chains from TTR. In addition, the structure reveals an interaction of the carboxy terminus of RBP at the protein-protein recognition interface. This interaction, which involves Leu-182 and Leu-183 of RBP, is consistent with the observation that naturally occurring truncated forms of the protein are more readily cleared from plasma than full-length RBP. Complex formation prevents extensive loss of RBP through glomerular filtration, and the loss of Leu-182 and Leu-183 would result in a decreased affinity of RBP for TTR. | ||
==About this Structure== | ==About this Structure== | ||
1QAB is a [http://en.wikipedia.org/wiki/Protein_complex Protein complex] structure of sequences from [http://en.wikipedia.org/wiki/Homo_sapiens Homo sapiens] with RTL as [http://en.wikipedia.org/wiki/ligand ligand]. Full crystallographic information is available from [http:// | 1QAB is a [http://en.wikipedia.org/wiki/Protein_complex Protein complex] structure of sequences from [http://en.wikipedia.org/wiki/Homo_sapiens Homo sapiens] with <scene name='pdbligand=RTL:'>RTL</scene> as [http://en.wikipedia.org/wiki/ligand ligand]. Full crystallographic information is available from [http://oca.weizmann.ac.il/oca-bin/ocashort?id=1QAB OCA]. | ||
==Reference== | ==Reference== | ||
| Line 18: | Line 18: | ||
[[Category: transthyretin]] | [[Category: transthyretin]] | ||
''Page seeded by [http:// | ''Page seeded by [http://oca.weizmann.ac.il/oca OCA ] on Thu Feb 21 14:37:32 2008'' | ||
Revision as of 15:37, 21 February 2008
|
The structure of human retinol binding protein with its carrier protein transthyretin reveals interaction with the carboxy terminus of RBP
OverviewOverview
Whether ultimately utilized as retinoic acid, retinal, or retinol, vitamin A is transported to the target cells as all-trans-retinol bound to retinol-binding protein (RBP). Circulating in the plasma, RBP itself is bound to transthyretin (TTR, previously referred to as thyroxine-binding prealbumin). In vitro one tetramer of TTR can bind two molecules of retinol-binding protein. However, the concentration of RBP in the plasma is limiting, and the complex isolated from serum is composed of TTR and RBP in a 1 to 1 stoichiometry. We report here the crystallographic structure at 3.2 A of the protein-protein complex of human RBP and TTR. RBP binds at a 2-fold axis of symmetry in the TTR tetramer, and consequently the recognition site itself has 2-fold symmetry: Four TTR amino acids (Arg-21, Val-20, Leu-82, and Ile-84) are contributed by two monomers. Amino acids Trp-67, Phe-96, and Leu-63 and -97 from RBP are flanked by the symmetry-related side chains from TTR. In addition, the structure reveals an interaction of the carboxy terminus of RBP at the protein-protein recognition interface. This interaction, which involves Leu-182 and Leu-183 of RBP, is consistent with the observation that naturally occurring truncated forms of the protein are more readily cleared from plasma than full-length RBP. Complex formation prevents extensive loss of RBP through glomerular filtration, and the loss of Leu-182 and Leu-183 would result in a decreased affinity of RBP for TTR.
About this StructureAbout this Structure
1QAB is a Protein complex structure of sequences from Homo sapiens with as ligand. Full crystallographic information is available from OCA.
ReferenceReference
The structure of human retinol-binding protein (RBP) with its carrier protein transthyretin reveals an interaction with the carboxy terminus of RBP., Naylor HM, Newcomer ME, Biochemistry. 1999 Mar 2;38(9):2647-53. PMID:10052934
Page seeded by OCA on Thu Feb 21 14:37:32 2008