4N7K:
reference: Structural and kinetic properties of Rhodobacter sphaeroides photosynthetic reaction centers containing exclusively Zn-coordinated bacteriochlorophyll as bacteriochlorin cofactors., Saer RG, Pan J, Hardjasa A, Lin S, Rosell F, Mauk AG, Woodbury NW, Murphy ME, Beatty JT, Biochim Biophys Acta. 2013 Dec 5;1837(3):366-374. doi:, 10.1016/j.bbabio.2013.11.015. PMID: 24316146

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