2a46
Crystal structures of amFP486, a cyan fluorescent protein from Anemonia majano, and variants
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OverviewOverview
Fluorescent proteins isolated from coral reef organisms can be roughly, grouped into four color classes by emission, cyan, green, yellow, and red., To gain insight into the structural basis for cyan emission, the crystal, structure of amFP486 (lambda(em)max = 486 nm) was determined by molecular, replacement, and the model was refined at 1.65-A resolution. The electron, density map reveals a chromophore formed from the tripeptide sequence, -K-Y-G- that is indistinguishable from that of GFP (lambda(em)max = 509, nm). However, the chromophore environment closely parallels those of the, yellow- and red-shifted homologs zFP538, DsRed, and eqFP611. Mutagenesis, was performed for Glu-150, Ala-165, His-199, and Glu-217, which are, immediately adjacent to the chromophore. His-199 and Ala-165 are key side, chains responsible for the blue shift, presumably by localizing, chromophore charge density on the phenolate moiety. Furthermore, in the, H199T mutant the fluorescence quantum yield is reduced by a factor of, approximately 110. The crystal structures of H199T (lambda(em)max = 515, nm) and E150Q (lambda(em)max = 506 nm) were determined. Remarkably, the, H199T structure reveals that the stacking interaction of His-199 with the, chromophore also controls the fluorescence efficiency, because the, chromophore is statistically distributed in a 1:1 ratio between cis, (fluorescent) and trans (nonfluorescent) conformations.
About this StructureAbout this Structure
2A46 is a Single protein structure of sequence from Anemonia majano with BME as ligand. Full crystallographic information is available from OCA.
ReferenceReference
Crystal structures and mutational analysis of amFP486, a cyan fluorescent protein from Anemonia majano., Henderson JN, Remington SJ, Proc Natl Acad Sci U S A. 2005 Sep 6;102(36):12712-7. Epub 2005 Aug 24. PMID:16120682
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