4KPP:
reference: Structural Basis for the Counter-Transport Mechanism of a H+/Ca2+ Exchanger., Nishizawa T, Kita S, Maturana AD, Furuya N, Hirata K, Kasuya G, Ogasawara S, Dohmae N, Iwamoto T, Ishitani R, Nureki O, Science. 2013 May 23. PMID: 23704374

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