The folding of hirudin adopts a mechanism of trial and error.
Reduced and denatured hirudin (65 amino acids and 3 disulfides) refolds in vitro to become an active molecule. The folding process adopts a mechanism of "trial and error" without predominant pathways. Throughout the entire folding process, the 6 cysteines were about equally involved in the disulfide shuffling. Among the first 20% of 3-disulfide species accumulated during the early phase of refolding, two-thirds were inactive and were reshuffled in the presence of thiol catalyst to regain correct disulfide pairing. When refolding was performed in the presence of strong denaturant (guanidinium chloride) without thiol catalyst, 8% of the active hirudin was obtained. This figure is close to the probability (6.7%) that would be expected from the random disulfide pairing of a molecule containing 6 sulfhydryl groups.
Chatrenet
B
B
Pharmaceuticals Research Laboratories, Ciba-Geigy Ltd., Basel, Switzerland.
Chang
J Y
JY
D000595:Amino Acid Sequence; D004220:Disulfides / Q000032:analysis; D010450:Endopeptidases / Q000378:metabolism; D006629:Hirudins / Q000737:chemistry*; D007700:Kinetics; D007834:Lasers; D013058:Mass Spectrometry; D008969:Molecular Sequence Data; D010449:Peptide Mapping; D011487:Protein Conformation; D011489:Protein Denaturation; D011994:Recombinant Proteins / Q000737:chemistry; D013379:Substrate Specificity
D004220:Disulfides; D006629:Hirudins; D011994:Recombinant Proteins; D010450:Endopeptidases