2hcg | pdb_00002hcg

Structure of S65T Y66F GFP variant after cyclization, carbon-carbon bond cleavage, and oxygen incorporation reactions

spinqualitylabelsall models 2hcg, resolution 1.35Å Show:Asymmetric Unit Biological Assembly Drag the structure with the mouse to rotate   Export Animated Image   Print3D Structural highlights 2hcg is a 1 chain structure with sequence from Aeqvi. Full crystallographic information is available from OCA. For a guided tour on the structure components use FirstGlance. Ligands: MG NonStd Res: C99 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. Evolutionary Conservation Check, as determined by ConSurfDB. You may read the explanation of the method and the full data available from ConSurf. Publication Abstract from PubMed The green fluorescent protein (GFP) creates its fluorophore by promoting spontaneous peptide backbone cyclization and amino acid oxidation chemistry on its own Ser65, Tyr66, Gly67 tripeptide sequence. Here we use high-resolution crystallography and mutational analyses to characterize GFP variants that undergo backbone cyclization followed by either anticipated chromophore synthesis via Y66F Calpha-Cbeta double-bond formation or unprecedented loss of a Y66F benzyl moiety via Calpha-Cbeta bond cleavage. We discovered a Y66F cleavage variant that subsequently incorporates an oxygen atom, likely from molecular oxygen, at the Y66 Calpha position. The post-translational products identified from these Y66F GFP structures support a common intermediate that partitions between Calpha-Cbeta oxidation and homolytic cleavage pathways. Our data indicate that Glu222 is the branchpoint control for this partitioning step and also influences subsequent oxygen incorporation reactions. From these results, we propose mechanisms for Y66F Calpha-Cbeta cleavage, oxygen incorporation, and chromophore biosynthesis with shared features that include radical chemistry. By revealing how GFP and RFP protein environments steer chemistry to favor fluorophore biosynthesis and disfavor alternative reactivity, we identify strategies for protein design. The proposed, common, one-electron oxidized, radical intermediate for post-translation modifications in the GFP family has general implications for how proteins drive and control spontaneous post-translational chemical modifications in the absence of metal ions. The case of the missing ring: radical cleavage of a carbon-carbon bond and implications for GFP chromophore biosynthesis.,Barondeau DP, Kassmann CJ, Tainer JA, Getzoff ED J Am Chem Soc. 2007 Mar 21;129(11):3118-26. Epub 2007 Feb 28. PMID:17326633 From MEDLINE®/PubMed®, a database of the U.S. National Library of Medicine. See Also Green Fluorescent Protein 3D structures

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