Fast folding kinetics and stabilization of apo-cytochrome c.
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.
Borgia
Alessandro
A
Dipartimento di Scienze Biochimiche, A. Rossi Fanelli, Sapienza, Università di Roma, Piazzale A. Moro 5, 00185 Rome, Italy.
Gianni
Stefano
S
Brunori
Maurizio
M
Travaglini-Allocatelli
Carlo
C
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*
D001426:Bacterial Proteins; D006418:Heme; D045304:Cytochromes c