1CTP:
reference: Structure of the mammalian catalytic subunit of cAMP-dependent protein kinase and an inhibitor peptide displays an open conformation., Karlsson R, Zheng J, Xuong N, Taylor SS, Sowadski JM, Acta Crystallogr D Biol Crystallogr. 1993 Jul 1;49(Pt 4):381-8. PMID: 15299513

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