title: Fast folding kinetics and stabilization of apo-cytochrome c.
abstract: It is generally accepted that in the c-type cytochromes the covalently bound heme plays a primary role in the acquisition of the folded state. Here, we show that a stabilized site-directed variant of apo-cyt c551 from Pseudomonas aeruginosa (Pa-apocyt F7A/W77F) retains native-like features in the presence of sodium sulfate even in the absence of heme. By time-resolved intrinsic fluorescence, we have evidence that Pa-apocyt F7A/W77F may acquire a compact, native-like conformation within microseconds. These results challenge current thinking about the role of the heme group in the folding of c-type cytochromes.
authors.affiliation: Dipartimento di Scienze Biochimiche, A. Rossi Fanelli, Sapienza, Università di Roma, Piazzale A. Moro 5, 00185 Rome, Italy.
authors.forename: Alessandro
authors.initials: A
authors.lastname: Borgia
authors.forename: Stefano
authors.initials: S
authors.lastname: Gianni
authors.forename: Maurizio
authors.initials: M
authors.lastname: Brunori
authors.forename: Carlo
authors.initials: C
authors.lastname: Travaglini-Allocatelli
mesh_terms: D001426:Bacterial Proteins / Q000737:chemistry* / Q000235:genetics; D045304:Cytochromes c / Q000737:chemistry* / Q000235:genetics; D004795:Enzyme Stability / Q000235:genetics; D006418:Heme / Q000737:chemistry; D007700:Kinetics; D016297:Mutagenesis, Site-Directed; D011487:Protein Conformation; D017510:Protein Folding; D011550:Pseudomonas aeruginosa / Q000201:enzymology*
chemical_list: D001426:Bacterial Proteins; D006418:Heme; D045304:Cytochromes c