2IW6:
reference: Dissecting the determinants of cyclin-dependent kinase 2 and cyclin-dependent kinase 4 inhibitor selectivity., Pratt DJ, Bentley J, Jewsbury P, Boyle FT, Endicott JA, Noble ME, J Med Chem. 2006 Sep 7;49(18):5470-7. PMID: 16942020

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