1ft6
REDUCED STATE OF CYTOCHROME C554 FROM NITROSOMONAS EUROPAEA
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OverviewOverview
Cytochrome c554 (cyt c554) is a tetra-heme cytochrome involved in the, oxidation of NH3 by Nitrosomonas europaea. The X-ray crystal structures of, both the oxidized and dithionite-reduced states of cyt c554 in a new, rhombohedral crystal form have been solved by molecular replacement, at, 1.6 A and 1.8 A resolution, respectively. Upon reduction, the conformation, of the polypeptide chain changes between residues 175 and 179, which are, adjacent to hemes III and IV. Cyt c554 displays conserved heme-packing, motifs that are present in other heme-containing proteins. Comparisons to, hydroxylamine oxidoreductase, the electron donor to cyt c554, and, cytochrome c nitrite reductase, an enzyme involved in nitrite, ammonification, reveal substantial structural similarity in the, polypeptide chain surrounding the heme core environment. The structural, determinants of these heme-packing motifs extend to the buried water, molecules that hydrogen bond to the histidine ligands to the heme iron. In, the original structure determination of a tetragonal crystal form, a cis, peptide bond between His129 and Phe130 was identified that appeared to be, stabilized by crystal contacts. In the rhombohedral crystal form used in, the present high-resolution structure determination, this peptide bond, adopts the trans conformation, but with disallowed angles of phi and psi.
About this StructureAbout this Structure
1FT6 is a Single protein structure of sequence from Nitrosomonas europaea with SO3, PO4, HEM and DTN as ligands. Full crystallographic information is available from OCA.
ReferenceReference
High-resolution structures of the oxidized and reduced states of cytochrome c554 from Nitrosomonas europaea., Iverson TM, Arciero DM, Hooper AB, Rees DC, J Biol Inorg Chem. 2001 Apr;6(4):390-7. PMID:11372197
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