4M6L:
reference: Divergent evolution of protein conformational dynamics in dihydrofolate reductase., Bhabha G, Ekiert DC, Jennewein M, Zmasek CM, Tuttle LM, Kroon G, Dyson HJ, Godzik A, Wilson IA, Wright PE, Nat Struct Mol Biol. 2013 Sep 29. doi: 10.1038/nsmb.2676. PMID: 24077226

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