5EXU:
reference: Evolution and characterization of a new reversibly photoswitching chromogenic protein, Dathail., Langan PS, Close DW, Coates L, Rocha RC, Ghosh K, Kiss C, Waldo G, Freyer J, Kovalevsky A, Bradbury AR, J Mol Biol. 2016 May 8;428(9 Pt A):1776-89. doi: 10.1016/j.jmb.2016.02.029. Epub , 2016 Mar 18. PMID: 27000644

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