View source for 1yfp

[[Image:1yfp.gif|left|200px]]<br /><applet load="1yfp" size="450" color="white" frame="true" align="right" spinBox="true" 
caption="1yfp, resolution 2.5&Aring;" />
'''STRUCTURE OF YELLOW-EMISSION VARIANT OF GFP'''<br />

==Overview==
BACKGROUND: Because of its ability to spontaneously generate its own, fluorophore, the green fluorescent protein (GFP) from the jellyfish, Aequorea victoria is used extensively as a fluorescent marker in molecular, and cell biology. The yellow fluorescent proteins (YFPs) have the longest, wavelength emissions of all GFP variants examined to date. This shift in, the spectrum is the result of a T203Y substitution (single-letter amino, acid code), a mutation rationally designed on the basis of the X-ray, structure of GFP S65T. RESULTS: We have determined the crystal structures, of YFP T203Y/S65G/V68L/S72A and YFP H148G to 2.5 and 2.6 A resolution, respectively. Both structures show clear electron density for nearly, coplanar pi-pi stacking between Tyr203 and the chromophore. The, chromophore has been displaced by nearly 1 A in comparison to other, available structures. Although the H148G mutation results in the, generation of a solvent channel to the chromophore cavity, intense, fluorescence is maintained. The chromophore in the intact protein can be, titrated, and the two variants have pKa values of 7.0 (YFP) and 8.0 (YFP, H148G). CONCLUSIONS: The observed red shift of the T203Y YFP variant is, proposed to be mainly due to the additional polarizability of the, pi-stacked Tyr203. The altered location of the chromophore suggests that, the exact positions of nearby residues are not crucial for the chemistry, of chromophore formation. The YFPs significantly extend the pH range over, which GFPs may be employed as pH indicators in live cells.

==About this Structure==
1YFP is a [http://en.wikipedia.org/wiki/Single_protein Single protein] structure of sequence from [http://en.wikipedia.org/wiki/Aequorea_victoria Aequorea victoria]. Full crystallographic information is available from [http://ispc.weizmann.ac.il/oca-bin/ocashort?id=1YFP OCA]. 

==Reference==
Structural basis of spectral shifts in the yellow-emission variants of green fluorescent protein., Wachter RM, Elsliger MA, Kallio K, Hanson GT, Remington SJ, Structure. 1998 Oct 15;6(10):1267-77. PMID:[http://ispc.weizmann.ac.il//pmbin/getpm?pmid=9782051 9782051]
[[Category: Aequorea victoria]]
[[Category: Single protein]]
[[Category: Elsliger, M.A.]]
[[Category: Hanson, G.T.]]
[[Category: Kallio, K.]]
[[Category: Remington, S.J.]]
[[Category: Wachter, R.M.]]
[[Category: bioluminescence]]
[[Category: fluorescent tag]]
[[Category: green fluorescent protein]]
[[Category: luminescence]]
[[Category: photoactive protein]]
[[Category: yellow-emission variant]]

''Page seeded by [http://ispc.weizmann.ac.il/oca OCA ] on Wed Nov 21 06:44:31 2007''