4DXP : Crystal Structure of a reconstructed Kaede-type Red Fluorescent Protein, LEA X121

  • Hanseong Kim (Contributor)
  • Raimund Fromme (Contributor)
  • Rebekka M. Wachter (Contributor)



Experimental Technique/Method:X-RAY DIFFRACTION
Release Date:2013-02-27
Deposition Date:2012-02-27
Revision Date:2015-04-22
Molecular Weight:26531.75
Macromolecule Type:Protein
Residue Count:228
Atom Site Count:1794

In proteins, functional divergence involves mutations that modify structure and dynamics. Here we provide experimental evidence for an evolutionary mechanism driven solely by long-range dynamic motions without significant backbone adjustments, catalytic group rearrangements, or changes in subunit assembly. Crystallographic structures were determined for several reconstructed ancestral proteins belonging to a GFP class frequently employed in superresolution microscopy. Their chain flexibility was analyzed using molecular dynamics and perturbation response scanning. The green-to-red photoconvertible phenotype appears to have arisen from a common green ancestor by migration of a knob-like anchoring region away from the active site diagonally across the β barrel fold. The allosterically coupled mutational sites provide active site conformational mobility via epistasis. We propose that light-induced chromophore twisting is enhanced in a reverse-protonated subpopulation, activating internal acid-base chemistry and backbone cleavage to enlarge the chromophore. Dynamics-driven hinge migration may represent a more general platform for the evolution of novel enzyme activities.
Date made available2013

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