4R6B:
reference: Rational design of enhanced photoresistance in a photoswitchable fluorescent protein., Duan C, Byrdin M, El Khatib M, Henry X, Adam V, Bourgeois D, Methods Appl Fluoresc. 2015 Jan 16;3(1):014004. doi:, 10.1088/2050-6120/3/1/014004. PMID: 29148481

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