Why is GFP pH-sensitive?
Outside of the pH 6-10 range, however, GFP fluorescence is modified. Spectroscopic and crystallographic data indicate that the protonation state of the chromophore is responsible for GFP pH sensitivity.
Are indicators pH-sensitive?
Generally, pH-sensitive indicators consist of two important parts; a pH-sensitive dye and solid support [7]. Alizarin or 1,2-dihydroxyanthraquinone (C14H8O4) is a natural dye and as an anthraquinone compound exhibits color changes at different pH from yellow in acidic conditions to red in basic conditions.
Is GFP pH-sensitive?
These findings suggest that GFP pH sensitivity involves simple protonation events at a pH of >5, but both protonation and conformational changes at lower pH. The pH sensitivity of GFP-F64L/S65T in cytoplasm and organelles was similar to that of purified GFP-F64L/S65T in saline.
Is Fluorescein pH dependent?
The neutral molecule and monoanion hare identical fluorescence spectra: an emission with maximum at 515 mu, extending to about 700 nm. However, the pH dependence of the fluorescence is quite complex and still has not been elucidated in detail.
Why is GFP so stable?
GFP is a single chain polypeptide of 238 amino acids (12). Most of these amino acids form ß sheets that are compacted through an antiparallel structure to form the barrel. The compact structure makes GFP very stable under a variety of conditions, including treatment with protease (1).
How stable is GFP?
After 10 min of contact, GFP exhibited the greatest stability in phosphate buffered solutions (pH 7) for the range of 20- 100 ppm of available chlorine, equivalent to the range of 40- 70 ppm in chlorinated WFI solution, (pH 11 ( 0.23) and to the range of 10-50 ppm in phosphate buffer (pH 6.86 ( 0.21).
What is the best pH indicator?
Some of the most widely-used pH testing tools are pH indicators, including phenolphthalein (range pH 8.2 to 10.0; colorless to pink), bromthymol blue (range pH 6.0 to 7.6; yellow to blue), and litmus (range pH 4.5 to 8.3; red to blue).
What plants make good pH indicators?
Beets, blackberries, grape juice, plums, turnip skin, and more all act as an edible natural pH indicator. They all have anthocyanin in them which makes the solution change color, but they also differ in that little side groups attached to the main molecule cause the color changes to vary between foods.
Is fluorescein acidic or basic?
At pH values from 2 to 4, fluorescein exists in its neutral species, and as the pH values become more basic, within the range of 4.3 to 6.4, the monoanionic form is present.
What is the effect of pH on fluorescence intensity and wavelength maxima for fluorescein?
Fluorescence spectra were obtained from suspensions of P. Two fluorescent motifs were identified; 410 nm excitation / 634 nm emission (peak A) and 398 nm excitation / 622 nm emission (peak B).
How is BFP different from GFP?
Unlike GFP, which at pH 8.5 and 7.5 is very resistant to SDS-induced denaturation, BFP readily lost about 20% of its fluorescence at pH 8.5 and about 60% fluorescence at pH 7.5.
Is EGFP a dimer?
In all seriousness, EGFP/GFP has a real nontrivial propensity to noncovalently dimerize. That means that your POI fused to GFP or another fluorescent protein (FP) could be forming dimers in cells.