1YHU:
reference: Sulfide binding is mediated by zinc ions discovered in the crystal structure of a hydrothermal vent tubeworm hemoglobin., Flores JF, Fisher CR, Carney SL, Green BN, Freytag JK, Schaeffer SW, Royer WE Jr, Proc Natl Acad Sci U S A 2005 Feb 22;102(8):2713-8. Epub 2005 Feb 14. PMID: 15710902

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