1FDD:
reference: Azotobacter vinelandii ferredoxin I. Aspartate 15 facilitates proton transfer to the reduced [3Fe-4S] cluster., Shen B, Martin LL, Butt JN, Armstrong FA, Stout CD, Jensen GM, Stephens PJ, La Mar GN, Gorst CM, Burgess BK, J Biol Chem 1993 Dec 5;268(34):25928-39. PMID: 8245026

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