4KPN:
reference: Structure and function of nucleoside hydrolases from Physcomitrella and maize catalyzing hydrolysis of purine, pyrimidine and cytokinin ribosides., Kopecna M, Blaschke H, Kopecny D, Vigouroux A, Koncitikova R, Novak O, Kotland O, Strnad M, Morera S, von Schwartzenberg K, Plant Physiol. 2013 Oct 29. PMID: 24170203

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