4zf3

Crystal structure of Green Fluorescent Protein (GFP); S65T, H148D; circular permutant ( 50-51)

spinqualitylabelsall models 4zf3, resolution 1.90Å Show:Asymmetric Unit Biological Assembly Drag the structure with the mouse to rotate   Export Animated Image   Print3D Structural highlights 4zf3 is a 2 chain structure with sequence from Aeqvi. Full crystallographic information is available from OCA. For a guided tour on the structure components use FirstGlance. NonStd Res: CRO Related: 4zf4, 4zf5 Gene: GFP (AEQVI) Resources: FirstGlance, OCA, PDBe, RCSB, PDBsum, ProSAT Function [GFP_AEQVI] Energy-transfer acceptor. Its role is to transduce the blue chemiluminescence of the protein aequorin into green fluorescent light by energy transfer. Fluoresces in vivo upon receiving energy from the Ca(2+)-activated photoprotein aequorin. Publication Abstract from PubMed Short hydrogen bonds and specifically low-barrier hydrogen bonds (LBHBs) have been the focus of much attention and controversy for their possible role in enzymatic catalysis. The green fluorescent protein (GFP) mutant S65T, H148D has been found to form a very short hydrogen bond between Asp148 and the chromophore resulting in significant spectral perturbations. Leveraging the unique autocatalytically formed chromophore and its sensitivity to this interaction we explore the consequences of proton affinity matching across this putative LBHB. Through the use of noncanonical amino acids introduced through nonsense suppression or global incorporation, we systematically modify the acidity of the GFP chromophore with halogen substituents. X-ray crystal structures indicated that the length of the interaction with Asp148 is unchanged at approximately 2.45 A while the absorbance spectra demonstrate an unprecedented degree of color tuning with increasing acidity. We utilized spectral isotope effects, isotope fractionation factors, and a simple 1D model of the hydrogen bond coordinate in order to gain insight into the potential energy surface and particularly the role that proton delocalization may play in this putative short hydrogen bond. The data and model suggest that even with the short donor-acceptor distance ( approximately 2.45 A) and near perfect affinity matching there is not a LBHB, that is, the barrier to proton transfer exceeds the H zero-point energy. Short Hydrogen Bonds and Proton Delocalization in Green Fluorescent Protein (GFP).,Oltrogge LM, Boxer SG ACS Cent Sci. 2015 Jun 24;1(3):148-56. doi: 10.1021/acscentsci.5b00160. Epub 2015, Jun 5. PMID:27162964 From MEDLINE®/PubMed®, a database of the U.S. National Library of Medicine. See Also Green Fluorescent Protein 3D structures

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