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| - | [[Image:2qle.jpg|left|200px]] | + | {{Seed}} |
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| | {{STRUCTURE_2qle| PDB=2qle | SCENE= }} | | {{STRUCTURE_2qle| PDB=2qle | SCENE= }} |
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| - | '''GFP/S205V mutant'''
| + | ===GFP/S205V mutant=== |
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| - | ==Overview==
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| - | Wild-type green fluorescent protein (wt-GFP) has a prominent absorbance band centered at approximately 395 nm, attributed to the neutral chromophore form. The green emission arising upon excitation of this band results from excited-state proton transfer (ESPT) from the chromophore hydroxyl, through a hydrogen-bond network proposed to consist of a water molecule and Ser205, to Glu222. Although evidence for Glu222 as a terminal proton acceptor has already been obtained, no evidence for the participation of Ser205 in the proton transfer process exists. To examine the role of Ser205 in the proton transfer, we mutated Ser205 to valine. However, the derived GFP variant S205V, upon excitation at 400 nm, still produces green fluorescence. Time-resolved emission spectroscopy suggests that ESPT contributes to the green fluorescence, and that the proton transfer takes place approximately 30 times more slowly than in wt-GFP. The crystal structure of S205V reveals rearrangement of Glu222 and Thr203, forming a new hydrogen-bonding network. We propose this network to be an alternative ESPT pathway with distinctive features that explain the significantly slowed rate of proton transfer. In support of this proposal, the double mutant S205V/T203V is shown to be a novel blue fluorescent protein containing a tyrosine-based chromophore, yet is incapable of ESPT. The results have implications for the detailed mechanism of ESPT and the photocycle of wt-GFP, in particular for the structures of spectroscopically identified intermediates in the cycle.
| + | The line below this paragraph, {{ABSTRACT_PUBMED_17965188}}, adds the Publication Abstract to the page |
| | + | (as it appears on PubMed at http://www.pubmed.gov), where 17965188 is the PubMed ID number. |
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| | + | {{ABSTRACT_PUBMED_17965188}} |
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| | ==About this Structure== | | ==About this Structure== |
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| | [[Category: Fluorescent protein]] | | [[Category: Fluorescent protein]] |
| | [[Category: Gfp mutant]] | | [[Category: Gfp mutant]] |
| - | ''Page seeded by [http://oca.weizmann.ac.il/oca OCA ] on Sun May 4 15:09:35 2008'' | + | |
| | + | ''Page seeded by [http://oca.weizmann.ac.il/oca OCA ] on Sun Jul 27 17:47:47 2008'' |
Revision as of 14:47, 27 July 2008
Template:STRUCTURE 2qle
GFP/S205V mutant
Template:ABSTRACT PUBMED 17965188
About this Structure
2QLE is a Single protein structure of sequence from Azotobacter vinelandii. Full crystallographic information is available from OCA.
Reference
An alternative excited-state proton transfer pathway in green fluorescent protein variant S205V., Shu X, Leiderman P, Gepshtein R, Smith NR, Kallio K, Huppert D, Remington SJ, Protein Sci. 2007 Dec;16(12):2703-10. Epub 2007 Oct 26. PMID:17965188
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