title: Crystallographic analysis of the intact metal centres [3Fe-4S](1+/0) and [4Fe-4S](2+/1+) in a Zn(2+) -containing ferredoxin.
abstract: Detailed structural models of di-cluster seven-iron ferredoxins constitute a valuable resource for folding and stability studies relating the metal cofactors' role in protein stability. The here reported, hemihedric twinned crystal structure at 2.0 A resolution from Acidianus ambivalens ferredoxin, shows an integral 103 residues, physiologically relevant native form composed by a N-terminal extension comprising a His/Asp Zn(2+) site and the ferredoxin (betaalphabeta)(2) core, which harbours intact clusters I and II, a [3Fe-4S](1+/0) and a [4Fe-4S](2+/1+) centres. This is in contrast with the previously available ferredoxin structure from Sulfolofus tokodai, which was obtained from an artificial oxidative conversion with two [3Fe-4S](1+/0) centres and poor definition around cluster II.
authors.affiliation: Instituto Tecnologia Química e Biológica, Universidade Nova de Lisboa, Av da República, Oeiras, Portugal. frazao@itqb.unl.pt
authors.forename: Carlos
authors.initials: C
authors.lastname: Frazão
authors.forename: David
authors.initials: D
authors.lastname: Aragão
authors.forename: Ricardo
authors.initials: R
authors.lastname: Coelho
authors.forename: Sónia S
authors.initials: SS
authors.lastname: Leal
authors.forename: Cláudio M
authors.initials: CM
authors.lastname: Gomes
authors.forename: Miguel
authors.initials: M
authors.lastname: Teixeira
authors.forename: Maria Arménia
authors.initials: MA
authors.lastname: Carrondo
mesh_terms: D041541:Acidianus / Q000737:chemistry*; D019843:Archaeal Proteins / Q000737:chemistry*; D018360:Crystallography, X-Ray; D005288:Ferredoxins / Q000737:chemistry*; D007501:Iron / Q000737:chemistry; D008670:Metals / Q000737:chemistry*; D008958:Models, Molecular; D055672:Static Electricity; D013455:Sulfur / Q000737:chemistry; D015032:Zinc / Q000737:chemistry
chemical_list: D019843:Archaeal Proteins; D005288:Ferredoxins; D008670:Metals; D013455:Sulfur; D007501:Iron; D015032:Zinc