Structural highlights
Publication Abstract from PubMedIn 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 beta 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. A hinge migration mechanism unlocks the evolution of green-to-red photoconversion in GFP-like proteins.,Kim H, Zou T, Modi C, Dorner K, Grunkemeyer TJ, Chen L, Fromme R, Matz MV, Ozkan SB, Wachter RM Structure. 2015 Jan 6;23(1):34-43. doi: 10.1016/j.str.2014.11.011. PMID:25565105[1] From MEDLINE®/PubMed®, a database of the U.S. National Library of Medicine. See AlsoReferences
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