1DS8:
reference: Determination of the binding sites of the proton transfer inhibitors Cd2+ and Zn2+ in bacterial reaction centers., Axelrod HL, Abresch EC, Paddock ML, Okamura MY, Feher G, Proc Natl Acad Sci U S A 2000 Feb 15;97(4):1542-7. PMID: 10677497

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