3AJ8:
reference: High-resolution X-ray study of the effects of deuteration on crystal growth and the crystal structure of proteinase K., Chatake T, Ishikawa T, Yanagisawa Y, Yamada T, Tanaka I, Fujiwara S, Morimoro Y, Acta Crystallogr Sect F Struct Biol Cryst Commun. 2011 Nov 1;67(Pt 11):1334-8., Epub 2011 Oct 25. PMID: 22102227

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