2i21
From Proteopedia
(New page: 200px<br /><applet load="2i21" size="450" color="white" frame="true" align="right" spinBox="true" caption="2i21, resolution 1.84Å" /> '''Bacteriorhodopsin/li...) |
|||
| Line 1: | Line 1: | ||
| - | [[Image:2i21.gif|left|200px]]<br /><applet load="2i21" size=" | + | [[Image:2i21.gif|left|200px]]<br /><applet load="2i21" size="350" color="white" frame="true" align="right" spinBox="true" |
caption="2i21, resolution 1.84Å" /> | caption="2i21, resolution 1.84Å" /> | ||
'''Bacteriorhodopsin/lipid complex, T46V mutant'''<br /> | '''Bacteriorhodopsin/lipid complex, T46V mutant'''<br /> | ||
==Overview== | ==Overview== | ||
| - | The X-ray diffraction structure of the non-illuminated D96A | + | The X-ray diffraction structure of the non-illuminated D96A bacteriorhodopsin mutant reveals structural changes as far away as 15 A from residue 96, at the retinal, Trp-182, Ala-215, and waters 501, 402, and 401. The Asp-to-Ala side-chain replacement breaks its hydrogen bond with Thr-46, and the resulting separation of the cytoplasmic ends of helices B and C is communicated to the retinal region through a chain of covalent and hydrogen bonds. The unexpected long-range consequences of the D96A mutation include breaking the hydrogen bond between O of Ala-215 and water 501 and the formation of a new hydrogen bond between water molecules 401 and 402 in the extracellular region. Because in the T46V mutant a new water molecule appears at Asp-96 and its hydrogen-bond to Ile-45 replaces Thr-46 as its link to helix B, the separation of helices B and C is smaller than that in D96A, and there are no atomic displacements elsewhere in the protein. Propagation of conformational changes along the chain between the retinal and Thr-46 had been observed earlier in the crystal structures of the D96N and E204Q mutants but in the trapped M state. Consistent with the perturbation of the retinal region in D96A, little change of the Thr-46 region occurs between the non-illuminated and M states of this mutant. It appears that a local perturbation can propagate along a track in both directions between the retinal and the Asp-96/Thr-46 pair, either from photoisomerization of the retinal in the wild-type protein in one case or from the D96A mutation in the other. |
==About this Structure== | ==About this Structure== | ||
| - | 2I21 is a [http://en.wikipedia.org/wiki/Single_protein Single protein] structure of sequence from [http://en.wikipedia.org/wiki/Halobacterium_salinarum Halobacterium salinarum] with RET, LI1 and SQU as [http://en.wikipedia.org/wiki/ligands ligands]. Full crystallographic information is available from [http:// | + | 2I21 is a [http://en.wikipedia.org/wiki/Single_protein Single protein] structure of sequence from [http://en.wikipedia.org/wiki/Halobacterium_salinarum Halobacterium salinarum] with <scene name='pdbligand=RET:'>RET</scene>, <scene name='pdbligand=LI1:'>LI1</scene> and <scene name='pdbligand=SQU:'>SQU</scene> as [http://en.wikipedia.org/wiki/ligands ligands]. Full crystallographic information is available from [http://oca.weizmann.ac.il/oca-bin/ocashort?id=2I21 OCA]. |
==Reference== | ==Reference== | ||
| Line 13: | Line 13: | ||
[[Category: Halobacterium salinarum]] | [[Category: Halobacterium salinarum]] | ||
[[Category: Single protein]] | [[Category: Single protein]] | ||
| - | [[Category: Lanyi, J | + | [[Category: Lanyi, J K.]] |
[[Category: Schobert, B.]] | [[Category: Schobert, B.]] | ||
[[Category: LI1]] | [[Category: LI1]] | ||
| Line 28: | Line 28: | ||
[[Category: serpentine]] | [[Category: serpentine]] | ||
| - | ''Page seeded by [http:// | + | ''Page seeded by [http://oca.weizmann.ac.il/oca OCA ] on Thu Feb 21 17:48:13 2008'' |
Revision as of 15:48, 21 February 2008
|
Bacteriorhodopsin/lipid complex, T46V mutant
Overview
The X-ray diffraction structure of the non-illuminated D96A bacteriorhodopsin mutant reveals structural changes as far away as 15 A from residue 96, at the retinal, Trp-182, Ala-215, and waters 501, 402, and 401. The Asp-to-Ala side-chain replacement breaks its hydrogen bond with Thr-46, and the resulting separation of the cytoplasmic ends of helices B and C is communicated to the retinal region through a chain of covalent and hydrogen bonds. The unexpected long-range consequences of the D96A mutation include breaking the hydrogen bond between O of Ala-215 and water 501 and the formation of a new hydrogen bond between water molecules 401 and 402 in the extracellular region. Because in the T46V mutant a new water molecule appears at Asp-96 and its hydrogen-bond to Ile-45 replaces Thr-46 as its link to helix B, the separation of helices B and C is smaller than that in D96A, and there are no atomic displacements elsewhere in the protein. Propagation of conformational changes along the chain between the retinal and Thr-46 had been observed earlier in the crystal structures of the D96N and E204Q mutants but in the trapped M state. Consistent with the perturbation of the retinal region in D96A, little change of the Thr-46 region occurs between the non-illuminated and M states of this mutant. It appears that a local perturbation can propagate along a track in both directions between the retinal and the Asp-96/Thr-46 pair, either from photoisomerization of the retinal in the wild-type protein in one case or from the D96A mutation in the other.
About this Structure
2I21 is a Single protein structure of sequence from Halobacterium salinarum with , and as ligands. Full crystallographic information is available from OCA.
Reference
Propagating structural perturbation inside bacteriorhodopsin: crystal structures of the M state and the D96A and T46V mutants., Lanyi JK, Schobert B, Biochemistry. 2006 Oct 3;45(39):12003-10. PMID:17002299
Page seeded by OCA on Thu Feb 21 17:48:13 2008
Categories: Halobacterium salinarum | Single protein | Lanyi, J K. | Schobert, B. | LI1 | RET | SQU | 7-transmembrane | Haloarchaea | Ion pump | Ion transport | Lipids | Membrane protein | Photoreceptor | Retinal protein | Serpentine
