title: A hinge migration mechanism unlocks the evolution of green-to-red photoconversion in GFP-like proteins.
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.
authors.affiliation: Department of Chemistry and Biochemistry, Arizona State University, Tempe, AZ 85287, USA.
authors.forename: Hanseong
authors.initials: H
authors.lastname: Kim
authors.affiliation: Center for Biological Physics, Department of Physics, Arizona State University, Tempe, AZ 85287, USA.
authors.forename: Taisong
authors.initials: T
authors.lastname: Zou
authors.affiliation: Institute for Cellular and Molecular Biology, The University of Texas, Austin, TX 78712, USA.
authors.forename: Chintan
authors.initials: C
authors.lastname: Modi
authors.affiliation: Department of Chemistry and Biochemistry, Arizona State University, Tempe, AZ 85287, USA.
authors.forename: Katerina
authors.initials: K
authors.lastname: Dörner
authors.affiliation: Department of Chemistry and Biochemistry, Arizona State University, Tempe, AZ 85287, USA.
authors.forename: Timothy J
authors.initials: TJ
authors.lastname: Grunkemeyer
authors.affiliation: Department of Chemistry and Biochemistry, Arizona State University, Tempe, AZ 85287, USA.
authors.forename: Liqing
authors.initials: L
authors.lastname: Chen
authors.affiliation: Department of Chemistry and Biochemistry, Arizona State University, Tempe, AZ 85287, USA.
authors.forename: Raimund
authors.initials: R
authors.lastname: Fromme
authors.affiliation: Section of Integrative Biology, The University of Texas, Austin, TX 78712, USA.
authors.forename: Mikhail V
authors.initials: MV
authors.lastname: Matz
authors.affiliation: Center for Biological Physics, Department of Physics, Arizona State University, Tempe, AZ 85287, USA. Electronic address: banu.ozkan@asu.edu.
authors.forename: S Banu
authors.initials: SB
authors.lastname: Ozkan
authors.affiliation: Department of Chemistry and Biochemistry, Arizona State University, Tempe, AZ 85287, USA; Center for Bioenergy and Photosynthesis, Arizona State University, Tempe, AZ 85287, USA. Electronic address: rwachter@asu.edu.
authors.forename: Rebekka M
authors.initials: RM
authors.lastname: Wachter
mesh_terms: D020134:Catalytic Domain / Q000235:genetics; D003116:Color; D018360:Crystallography, X-Ray; D019143:Evolution, Molecular; D005453:Fluorescence; D049452:Green Fluorescent Proteins / Q000737:chemistry* / Q000235:genetics*; D008164:Luminescent Proteins / Q000737:chemistry* / Q000235:genetics*; D008958:Models, Molecular; D056004:Molecular Dynamics Simulation; D009038:Motion; D009154:Mutation; D017510:Protein Folding; D055550:Protein Stability; D017434:Protein Structure, Tertiary / Q000235:genetics; D000097573:Red Fluorescent Protein
chemical_list: D049452:Green Fluorescent Proteins; D008164:Luminescent Proteins; D000097573:Red Fluorescent Protein