From Proteopedia
(Difference between revisions)
proteopedia linkproteopedia link
|
|
| Line 1: |
Line 1: |
| - | [[Image:1vgo.gif|left|200px]] | + | {{Seed}} |
| | + | [[Image:1vgo.png|left|200px]] |
| | | | |
| | <!-- | | <!-- |
| Line 9: |
Line 10: |
| | {{STRUCTURE_1vgo| PDB=1vgo | SCENE= }} | | {{STRUCTURE_1vgo| PDB=1vgo | SCENE= }} |
| | | | |
| - | '''Crystal Structure of Archaerhodopsin-2'''
| + | ===Crystal Structure of Archaerhodopsin-2=== |
| | | | |
| | | | |
| - | ==Overview==
| + | <!-- |
| - | Archaerhodopsin-1 and -2 (aR-1 and aR-2) are light-driven proton pumps found in Halorubrum sp. aus-1 and -2, which share 55-58% sequence identity with bacteriorhodopsin (bR), a proton pump found in Halobacterium salinarum. In this study, aR-1 and aR-2 were crystallized into 3D crystals belonging to P4(3)2(1)2 (a = b = 128.1 A, c = 117.6 A) and C222(1) (a = 122.9 A, b = 139.5 A, c = 108.1 A), respectively. In both the crystals, the asymmetric unit contains two protein molecules with slightly different conformations. Each subunit is composed of seven helical segments as seen in bR but, unlike bR, aR-1 as well as aR-2 has a unique omega loop near the N terminus. It is found that the proton pathway in the extracellular half (i.e. the proton release channel) is more opened in aR-2 than in aR-1 or bR. This structural difference accounts for a large variation in the pKa of the acid purple-to-blue transition among the three proton pumps. All the aromatic residues surrounding the retinal polyene chain are conserved among the three proton pumps, confirming a previous argument that these residues are required for the stereo-specificity of the retinal isomerization. In the cytoplasmic half, the region surrounded by helices B, C and G is highly conserved, while the structural conservation is very low for residues extruded from helices E and F. Structural conservation of the hydrophobic residues located on the proton uptake pathway suggests that their precise arrangement is necessary to prevent a backward flow of proton in the presence of a large pH gradient and membrane potential. An empty cavity is commonly seen in the vicinity of Leu93 contacting the retinal C13 methyl. Existence of such a cavity is required to allow a large rotation of the side-chain of Leu93 at the early stage of the photocycle, which has been shown to accompany water translocation across the Schiff base.
| + | The line below this paragraph, {{ABSTRACT_PUBMED_16540121}}, adds the Publication Abstract to the page |
| | + | (as it appears on PubMed at http://www.pubmed.gov), where 16540121 is the PubMed ID number. |
| | + | --> |
| | + | {{ABSTRACT_PUBMED_16540121}} |
| | | | |
| | ==About this Structure== | | ==About this Structure== |
| Line 30: |
Line 34: |
| | [[Category: Proton transport]] | | [[Category: Proton transport]] |
| | [[Category: Retinal-binding protein]] | | [[Category: Retinal-binding protein]] |
| - | ''Page seeded by [http://oca.weizmann.ac.il/oca OCA ] on Wed Jun 11 10:53:33 2008'' | + | |
| | + | ''Page seeded by [http://oca.weizmann.ac.il/oca OCA ] on Mon Jul 28 10:25:16 2008'' |
Revision as of 07:25, 28 July 2008
Template:STRUCTURE 1vgo
Crystal Structure of Archaerhodopsin-2
Template:ABSTRACT PUBMED 16540121
About this Structure
1VGO is a Single protein structure of sequence from Halobacterium sp.. Full crystallographic information is available from OCA.
Reference
Crystal structures of archaerhodopsin-1 and -2: Common structural motif in archaeal light-driven proton pumps., Enami N, Yoshimura K, Murakami M, Okumura H, Ihara K, Kouyama T, J Mol Biol. 2006 May 5;358(3):675-85. Epub 2006 Mar 3. PMID:16540121
Page seeded by OCA on Mon Jul 28 10:25:16 2008
