3SFM:
reference: Novel crystallization conditions for tandem variant R67 DHFR yield a wild-type crystal structure., Yachnin BJ, Colin DY, Volpato JP, Ebert M, Pelletier JN, Berghuis AM, Acta Crystallogr Sect F Struct Biol Cryst Commun. 2011 Nov 1;67(Pt, 11):1316-22. Epub 2011 Oct 25. PMID: 22102224

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