The chromophores of fluorescent proteins (FPs) form through self-catalyzed posttranslational modifications (1). In the original green FP (GFP) isolated from the jellyfish Aequorea victoria, Ser65, Tyr66, and Gly67 residues form the 4-(p-hydroxybenzylidene)-5-imidazolinone (HBI) chromophore that contains a phenolate ring (P-ring), an imidazoline ring (I-ring), and a monomethine bridge (1). The protein cage excludes water that can quench fluorescence, but also enhances the fluorescence quantum yield (FQY) by restricting bond-twisting photoisomerization of the HBI chromophore. However, the protein could also improve FQY through electrostatic effects. As reported on page 76 of this issue, Romei et al. (2) studied the effect of introducing groups that donate or withdraw chromophore electrons on the FQY of the photoswitchable FP Dronpa2 (3).
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Electrostatics affect the glow, Science, 03 Jan 2020
Science, 3 January, 2020，DOI：https://doi.org/10.1126/science.aba0571
Electrostatics affect the glow
Cheng Hu, Xiaohong Liu, Jiangyun Wang
Abstract
The chromophores of fluorescent proteins (FPs) form through self-catalyzed posttranslational modifications (1). In the original green FP (GFP) isolated from the jellyfish Aequorea victoria, Ser65, Tyr66, and Gly67 residues form the 4-(p-hydroxybenzylidene)-5-imidazolinone (HBI) chromophore that contains a phenolate ring (P-ring), an imidazoline ring (I-ring), and a monomethine bridge (1). The protein cage excludes water that can quench fluorescence, but also enhances the fluorescence quantum yield (FQY) by restricting bond-twisting photoisomerization of the HBI chromophore. However, the protein could also improve FQY through electrostatic effects. As reported on page 76 of this issue, Romei et al. (2) studied the effect of introducing groups that donate or withdraw chromophore electrons on the FQY of the photoswitchable FP Dronpa2 (3).
文章链接：https://science.sciencemag.org/content/367/6473/26