4A1U:
reference: Evaluation of Diverse alpha/beta-Backbone Patterns for Functional alpha-Helix Mimicry: Analogues of the Bim BH3 Domain., Boersma MD, Haase HS, Peterson-Kaufman KJ, Lee EF, Clarke OB, Colman PM, Smith BJ, Horne WS, Fairlie WD, Gellman SH, J Am Chem Soc. 2011 Dec 8. PMID: 22040025

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