4E3U:
reference: Proline: Mother Nature's cryoprotectant applied to protein crystallography., Pemberton TA, Still BR, Christensen EM, Singh H, Srivastava D, Tanner JJ, Acta Crystallogr D Biol Crystallogr. 2012 Aug;68(Pt 8):1010-8. Epub 2012 Jul 17. PMID: 22868767

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