title: Reduced and oxidized cytochrome c4 exhibit differences in dynamics.
abstract: The temperature-dependent dynamics of the fully reduced and fully oxidized forms of Pseudomonas stutzeri cytochrome c4 have been studied by Mössbauer spectroscopy. Prior to the dynamic analysis, an efficient labelling strategy has been developed for the expression of highly enriched (57)Fe recombinant cytochrome c4. Subsequently, the protein has been purified to apparent homogeneity. Mössbauer measurements were recorded in the temperature range 77-240 K for both protein forms. A detailed analysis of the high quality spectra is presented. Based on the information obtained from Mössbauer spectroscopy, similarities and differences between cytochrome c4, cytochrome c and HiPIP are discussed. The obtained results reveal that (a) cytochrome c4 exists in pure low spin electronic configuration in both oxidation states in the temperature range 77-240 K, (b) the heme pocket is more relaxed in cytochrome c4 than in cytochrome c, (c) the reduced cytochrome c4 is the most flexible at low temperatures, and (d) protein specific dynamics are most distinct in the oxidized protein.
authors.affiliation: Department of Chemistry, Technical University of Denmark, 2800, Lyngby, Denmark. hemc@kemi.dtu.dk
authors.forename: Anne
authors.initials: A
authors.lastname: Marie Jørgensen
authors.forename: Fritz
authors.initials: F
authors.lastname: Parak
authors.forename: Hans E
authors.initials: HE
authors.lastname: M Christensen
mesh_terms: D003574:Cytochrome c Group / Q000737:chemistry*; D007501:Iron / Q000737:chemistry*; D010084:Oxidation-Reduction; D011487:Protein Conformation; D015204:Spectroscopy, Mossbauer / Q000379:methods; D013696:Temperature
chemical_list: D003574:Cytochrome c Group; C034186:cytochrome C4; D007501:Iron