1xmz
From Proteopedia
(New page: 200px<br /><applet load="1xmz" size="450" color="white" frame="true" align="right" spinBox="true" caption="1xmz, resolution 1.38Å" /> '''Crystal structure of...) |
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| - | [[Image:1xmz.gif|left|200px]]<br /><applet load="1xmz" size=" | + | [[Image:1xmz.gif|left|200px]]<br /><applet load="1xmz" size="350" color="white" frame="true" align="right" spinBox="true" |
caption="1xmz, resolution 1.38Å" /> | caption="1xmz, resolution 1.38Å" /> | ||
'''Crystal structure of the dark state of kindling fluorescent protein kfp from anemonia sulcata'''<br /> | '''Crystal structure of the dark state of kindling fluorescent protein kfp from anemonia sulcata'''<br /> | ||
==Overview== | ==Overview== | ||
| - | When the nonfluorescent chromoprotein asFP595 from Anemonia sulcata is | + | When the nonfluorescent chromoprotein asFP595 from Anemonia sulcata is subjected to sufficiently intense illumination near the absorbance maximum (lambda(abs)(max) = 568 nm), it undergoes a remarkable transition, termed "kindling", to a long-lived fluorescent state (lambda(em)(max) = 595 nm). In the dark recovery phase, the kindled state relaxes thermally on a time scale of seconds or can instantly be reverted upon illumination at 450 nm. The kindling phenomenon is enhanced by the Ala143 --> Gly point mutation, which slows the dark recovery time constant to 100 s at room temperature and increases the fluorescence quantum yield. To investigate the chemical nature of the chromophore and the possible role of chromophore isomerization in the kindling phenomenon, we determined the crystal structure of the "kindling fluorescent protein" asFP595-A143G (KFP) in the dark-adapted state at 1.38 A resolution and 100 K. The chromophore, derived from the Met63-Tyr64-Gly65 tripeptide, closely resembles that of the nonfluorescent chromoprotein Rtms5 in that the configuration is trans about the methylene bridge and there is substantial distortion from planarity. Unlike in Rtms5, in the native protein the polypeptide backbone is cleaved between Cys62 and Met63. The size and shape of the chromophore pocket suggest that the cis isomer of the chromophore could also be accommodated. Within the pocket, partially disordered His197 displays two conformations, which may constitute a binary switch that stabilizes different chromophore configurations. The energy barrier for thermal relaxation was found by Arrhenius plot analysis to be approximately 71 kJ/mol, somewhat higher than the value of approximately 55 kJ/mol observed for cis-trans isomerization of a model chromophore in solution. |
==About this Structure== | ==About this Structure== | ||
| - | 1XMZ is a [http://en.wikipedia.org/wiki/Single_protein Single protein] structure of sequence from [http://en.wikipedia.org/wiki/Anemonia_sulcata Anemonia sulcata] with NH2 and BME as [http://en.wikipedia.org/wiki/ligands ligands]. Full crystallographic information is available from [http:// | + | 1XMZ is a [http://en.wikipedia.org/wiki/Single_protein Single protein] structure of sequence from [http://en.wikipedia.org/wiki/Anemonia_sulcata Anemonia sulcata] with <scene name='pdbligand=NH2:'>NH2</scene> and <scene name='pdbligand=BME:'>BME</scene> as [http://en.wikipedia.org/wiki/ligands ligands]. Full crystallographic information is available from [http://oca.weizmann.ac.il/oca-bin/ocashort?id=1XMZ OCA]. |
==Reference== | ==Reference== | ||
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[[Category: Anemonia sulcata]] | [[Category: Anemonia sulcata]] | ||
[[Category: Single protein]] | [[Category: Single protein]] | ||
| - | [[Category: Anstrom, D | + | [[Category: Anstrom, D M.]] |
| - | [[Category: Chudakov, D | + | [[Category: Chudakov, D M.]] |
[[Category: Kallio, K.]] | [[Category: Kallio, K.]] | ||
| - | [[Category: Leary, S | + | [[Category: Leary, S O.]] |
| - | [[Category: Quillin, M | + | [[Category: Quillin, M L.]] |
| - | [[Category: Remington, S | + | [[Category: Remington, S J.]] |
[[Category: Shu, X.]] | [[Category: Shu, X.]] | ||
[[Category: BME]] | [[Category: BME]] | ||
| Line 26: | Line 26: | ||
[[Category: fluorescent protein]] | [[Category: fluorescent protein]] | ||
| - | ''Page seeded by [http:// | + | ''Page seeded by [http://oca.weizmann.ac.il/oca OCA ] on Thu Feb 21 15:56:32 2008'' |
Revision as of 13:56, 21 February 2008
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Crystal structure of the dark state of kindling fluorescent protein kfp from anemonia sulcata
Overview
When the nonfluorescent chromoprotein asFP595 from Anemonia sulcata is subjected to sufficiently intense illumination near the absorbance maximum (lambda(abs)(max) = 568 nm), it undergoes a remarkable transition, termed "kindling", to a long-lived fluorescent state (lambda(em)(max) = 595 nm). In the dark recovery phase, the kindled state relaxes thermally on a time scale of seconds or can instantly be reverted upon illumination at 450 nm. The kindling phenomenon is enhanced by the Ala143 --> Gly point mutation, which slows the dark recovery time constant to 100 s at room temperature and increases the fluorescence quantum yield. To investigate the chemical nature of the chromophore and the possible role of chromophore isomerization in the kindling phenomenon, we determined the crystal structure of the "kindling fluorescent protein" asFP595-A143G (KFP) in the dark-adapted state at 1.38 A resolution and 100 K. The chromophore, derived from the Met63-Tyr64-Gly65 tripeptide, closely resembles that of the nonfluorescent chromoprotein Rtms5 in that the configuration is trans about the methylene bridge and there is substantial distortion from planarity. Unlike in Rtms5, in the native protein the polypeptide backbone is cleaved between Cys62 and Met63. The size and shape of the chromophore pocket suggest that the cis isomer of the chromophore could also be accommodated. Within the pocket, partially disordered His197 displays two conformations, which may constitute a binary switch that stabilizes different chromophore configurations. The energy barrier for thermal relaxation was found by Arrhenius plot analysis to be approximately 71 kJ/mol, somewhat higher than the value of approximately 55 kJ/mol observed for cis-trans isomerization of a model chromophore in solution.
About this Structure
1XMZ is a Single protein structure of sequence from Anemonia sulcata with and as ligands. Full crystallographic information is available from OCA.
Reference
Kindling fluorescent protein from Anemonia sulcata: dark-state structure at 1.38 A resolution., Quillin ML, Anstrom DM, Shu X, O'Leary S, Kallio K, Chudakov DM, Remington SJ, Biochemistry. 2005 Apr 19;44(15):5774-87. PMID:15823036
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