The fluorophore is part of the polypeptide chain i. If you press the buttom below, it will show the connection. Tsien et al. The loss of water then forms the imidazolinone intermediate. The process is completely auto-catalytic such that there are no known co-factors or enzymatic components required. The hydrogen bonding created by the presence of the water molecules, however, helps to link the buried of Glu and Gln 69 that would otherwise be actively polar. The opposite side of the chromophore, however, is within close proximity of several aromatic and polar side chains.
Several between the surrounding residues and the chromophore are present including: hydrogen bonds of His , Thr , and Ser with the phenolic hydroxyl of Tyr 66 ; Arg 96 and Gln 94 with the carbonyl of the imidazolidinone ring; and hydrogen bonds of Glu with the side chain of Thr Additional hydrogen bonding in the area around the chromophore helps to stabilize Arg 96 in the protonated form, which suggests the presence of a partial negative charge on the carbonyl oxygen of the imidazolidinone ring in the deprotonated fluorophore.
These two elements point to a fluorescence that is not inherent to the isolated fluorophore, [2] [9] but rather from the auto-catalytic cyclization of the polypeptide sequence Ser 65 Tyr 66 Gly 67 and subsequent oxidation of Tyr According to Phillips , fluorophore formation is due to the close proximity of the backbone atoms between Ser In fact, no functional fluorescent proteins have been found in which any other amino acid other than glycine was found at position Even so, there are still proteins that have this specific sequence, therefore, there must be another inherent property to GFP that is still left misunderstood.
He found that Arg 96 actually acts as a by withdrawing electrons through hydrogen bonding with the carbonyl oxygen of Ser 65 to activate the carbonyl carbon for nucleophilic attack by the amide nitrogen of Gly This mechanism was further supported by ab initio calculations, as well as database searches of similar compounds and protein sequences.
Many mutant green fluorescent proteins have been developed in order to further understand the structure and mechanism of the fluorophore. The first mutagenesis studies simply of the amino acid sequence. NOTE: The structure represented here is already truncated at the carbonyl terminus.
Shortening the polypeptide by more than seven amino acids from either terminus lead to a total loss of fluorescence, as well as a complete failure to absorb light at the traditional wavelengths. This is most likely due to the structure of the protein. The last seven amino acid residues of the carboxyl terminus are roughly disordered, and thus do not interfere with the overall structure. Length: Mass Da : 26, It is useful for tracking sequence updates.
The algorithm is described in the ISO standard. Full view. These are stable identifiers and should be used to cite UniProtKB entries. Upon integration into UniProtKB, each entry is assigned a unique accession number, which is called 'Primary citable accession number'.
See complete history. Do not show this banner again. BioCyc i. Recommended name: Green fluorescent protein. This is known as the 'taxonomic identifier' or 'taxid'. It lists the nodes as they appear top-down in the taxonomic tree, with the more general grouping listed first. In mut2. In mut3. In EBFP1. In EBFP2. In R; matures to the red-emitting state with excitation and emission maxima at and nm, respectively; when associated with L; N; Q; A; V and L In Venus; leads to yellow fluorescence, improved maturation and reduced environmental sensitivity; when associated with L; G; L; A; T; A; G and Y In ECFP; leads to cyan fluorescence, folds faster and more efficiently at 37 degrees Celsius and has superior solubility and brightness; when associated with T; W; I; T and A In Cerulean; leads to improved quantum yield, a higher extinction coefficient and is 2.
In GFPmut 1; red-shifts by about nm the excitation maxima, permitting efficient excitation at nm and increases fluorescence; when associated with T In GFPmut 3; highly fluorescent mutant when excited at nm; when associated with A Highly fluorescent; when associated with Y; L and A In Topaz; shifts the major emission and exitation peak up to 20 nm; when associated with A; R and Y In Venus; leads to yellow fluorescence, improved maturation and reduced environmental sensitivity; when associated with L; L; L; A; T; A; G and Y In ECFP; leads to cyan fluorescence, folds faster and more efficiently at 37 degrees Celsius and has superior solubility and brightness; when associated with L; W; I; T and A In Azurite; shifts the excitation and emission spectra to shorter wavelengths and increases quantum yields compared to BFP; when associated with R; F; I and R In ECFP; leads to cyan fluorescence, folds faster and more efficiently at 37 degrees Celsius and has superior solubility and brightness; when associated with L; T; I; T and A In GFPmut 2; red-shifts by about nm the excitation maxima, permitting efficient excitation at nm and increases fluorescence; when associated with A and A Unspecified ID: Budding yeast Saccharomyces cerevisiae ID: Maturation time of enhanced green fluorescent protein EGFP in vitro.
Generic ID: Green Fluorescent Protein Green fluorescent protein GFP is a protein in the jellyfish Aequorea Victoria that exhibits green fluorescence when exposed to light. Ward, and Douglas C. Chalfie, Martin. Davenport, Demorest and Joseph Nicol. Harvey, Edmund. Luminescence in the coelenterates. Hastings, John, and James Morin. Matz, Mikhail V. Fradkov, Yulii A. Labas, Aleksandr P. Savitsky, Andrey G. Zaraisky, Mikhail L.
Markelov, and Sergey A. Nienhaus, Ulrich. Prasher, Douglas C, Virgina K. Eckenrodeb, William W. Ward, Frank G. Prendergastd, and Milton J. Shimomura, Osamu, Frank H. Johnson, and Yo Saiga.
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