title: X-Ray structure of the cytochrome c2 isolated from Paracoccus denitrificans refined to 1.7-A resolution.
abstract: The cytochrome c2 (formerly c550) isolated from Paracoccus denitrificans is one of the larger bacterial c-type proteins examined thus far. The molecular structure of this cytochrome has been redetermined and refined to 1.7-A resolution with a crystallographic R-factor of 17.5% for all measured X-ray data. Like other, smaller c-type cytochromes, the molecule consists of five alpha-helices that wrap around the heme group. In addition, this bacterial cytochrome contains two strands of anti-parallel beta-sheet, five Type I turns, and three Type II turns. The present model differs from the originally determined structure in several regions including the N-terminus, the loop delineated by Asp 25 to Lys 31, the region defined by Trp 86 to Val 88, and the C-terminus. A total of 103 water molecules has been positioned into the electron density map. Six of these waters are directly involved in heme binding.
authors.affiliation: Institute for Enzyme Research, Graduate School, University of Wisconsin, Madison 53705.
authors.forename: M M
authors.initials: MM
authors.lastname: Benning
authors.forename: T E
authors.initials: TE
authors.lastname: Meyer
authors.forename: H M
authors.initials: HM
authors.lastname: Holden
mesh_terms: D000595:Amino Acid Sequence; D018360:Crystallography, X-Ray / Q000379:methods; D003574:Cytochrome c Group / Q000737:chemistry* / Q000302:isolation & purification; D045362:Cytochromes c2; D008958:Models, Molecular; D008969:Molecular Sequence Data; D010231:Paracoccus denitrificans / Q000378:metabolism*; D017433:Protein Structure, Secondary
chemical_list: D003574:Cytochrome c Group; D045362:Cytochromes c2