A hinge migration mechanism unlocks the evolution of green-to-red photoconversion in GFP-like proteins

Hanseong Kim, Taisong Zou, Chintan Modi, Katerina Dörner, Timothy J. Grunkemeyer, Liqing Chen, Raimund Fromme, Mikhail V. Matz, Sefika Ozkan, Rebekka Wachter

Research output: Contribution to journalArticle

21 Scopus citations

Abstract

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.

Original languageEnglish (US)
Pages (from-to)34-43
Number of pages10
JournalStructure
Volume23
Issue number1
DOIs
StatePublished - Jan 6 2015

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ASJC Scopus subject areas

  • Structural Biology
  • Molecular Biology

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