2PHY: Photoactive Yellow Protein, Dark State (Unbleached)
reference: 1.4 A structure of photoactive yellow protein, a cytosolic photoreceptor: unusual fold, active site, and chromophore., Borgstahl GE, Williams DR, Getzoff ED, Biochemistry 1995 May 16;34(19):6278-87. PMID: 7756254

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