3kpx

Crystal Structure Analysis of photoprotein clytin

spinqualitylabelsall models 3kpx, resolution 1.90Å Show:Asymmetric Unit Biological Assembly Drag the structure with the mouse to rotate   Export Animated Image   Print3D Structural highlights 3kpx is a 1 chain structure with sequence from Clytia gregaria. Full crystallographic information is available from OCA. For a guided tour on the structure components use FirstGlance. Method: X-ray diffraction, Resolution 1.899Å Ligands: CA, CZH Resources: FirstGlance, OCA, PDBe, RCSB, PDBsum, ProSAT Function D7PM14_CLYGR 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 Forster resonance energy transfer within a protein-protein complex has previously been invoked to explain emission spectral modulation observed in several bioluminescence systems. Here we present a spatial structure of a complex of the Ca(2+)-regulated photoprotein clytin with its green-fluorescent protein (cgGFP) from the jellyfish Clytia gregaria, and show that it accounts for the bioluminescence properties of this system in vitro. We adopted an indirect approach of combining x-ray crystallography determined structures of the separate proteins, NMR spectroscopy, computational docking, and mutagenesis. Heteronuclear NMR spectroscopy using variously (15)N,(13)C,(2)H-enriched proteins enabled assignment of backbone resonances of more than 94% of the residues of both proteins. In a mixture of the two proteins at millimolar concentrations, complexation was inferred from perturbations of certain (1)H-(15)N HSQC-resonances, which could be mapped to those residues involved at the interaction site. A docking computation using HADDOCK was employed constrained by the sites of interaction, to deduce an overall spatial structure of the complex. Contacts within the clytin-cgGFP complex and electrostatic complementarity of interaction surfaces argued for a weak protein-protein complex. A weak affinity was also observed by isothermal titration calorimetry (K(D) = 0.9 mm). Mutation of clytin residues located at the interaction site reduced the degree of protein-protein association concomitant with a loss of effectiveness of cgGFP in color-shifting the bioluminescence. It is suggested that this clytin-cgGFP structure corresponds to the transient complex previously postulated to account for the energy transfer effect of GFP in the bioluminescence of aequorin or Renilla luciferase. NMR-derived Topology of a GFP-photoprotein Energy Transfer Complex.,Titushin MS, Feng Y, Stepanyuk GA, Li Y, Markova SV, Golz S, Wang BC, Lee J, Wang J, Vysotski ES, Liu ZJ J Biol Chem. 2010 Dec 24;285(52):40891-900. Epub 2010 Oct 6. PMID:20926380 From MEDLINE®/PubMed®, a database of the U.S. National Library of Medicine.

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