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Publication Abstract from PubMed

Ferredoxin I from Azotobacter vinelandii (AvFdI) is an iron-sulfur protein composed of 106 amino acids, seven Fe atoms and eight inorganic S* atoms. A crystallographic redetermination of its structure showed the originally reported structure to be incorrect. We report here the crystal structure of AvFdI at pH 6.5. Extensive refinement has led to a final R value of 0.170 for all 6986 non-extinct reflections in the range 10-2.3 A using a solvent model which includes 98 discrete solvent atoms with occupancies between 0.3 and 1.0 and an average B value of 22.5 A(2). The first half of the peptide chain closely resembles that of the 55-residue ferredoxin from Peptococcus aerogenes (PaFd), while the remainder consists of three turns of helix and a series of loops which form a cap over part of the molecular core. Despite the similarities in structure and surroundings, the corresponding 4Fe4S* clusters in PaFd and AvFdI have strikingly different redox potentials; a possible explanation has been sought in the differing hydration models for the two molecules.

Structure at pH 6.5 of ferredoxin I from Azotobacter vinelandii at 2.3 A resolution.,Merritt EA, Stout GH, Turley S, Sieker LC, Jehsen LH, Orme-Johnson WH Acta Crystallogr D Biol Crystallogr. 1993 Mar 1;49(Pt 2):272-81. PMID:15299532^[1]

From MEDLINE®/PubMed®, a database of the U.S. National Library of Medicine.