Binding of defined regions of a polypeptide to GroEL and its implications for chaperonin-mediated protein folding.
Unfolded rhodanese in a complex with the chaperonin GroEL was subjected to limited proteolysis. Sequence analysis indentified a GroEL-bound fragment of approximately 11,000 M(r) and a well defined fragment of approximately 7,000 M(r) from the two homologous domains of rhodanese. The shorter segment contains one hydrophobic and one amphiphilic alpha-helix mapping to the domain interface while the other fragment contains the homologous regions and an additional hydrophobic helix. Our results suggest a mechanism for the GroEL-mediated folding of rhodanese in which the domain-forming regions of the polypeptide are kept apart and are then released, perhaps sequentially, resulting in correct folding.
Hlodan
R
R
Cellular Biochemistry and Biophysics Program, Memorial Sloan-Kettering Cancer Center, New York, New York 10021, USA.
Tempst
P
P
Hartl
F U
FU
D000595:Amino Acid Sequence; D000818:Animals; D002417:Cattle; D018834:Chaperonin 60 / Q000378:metabolism*; D018833:Chaperonins / Q000378:metabolism*; D066298:In Vitro Techniques; D046911:Macromolecular Substances; D008958:Models, Molecular; D008969:Molecular Sequence Data; D010446:Peptide Fragments / Q000378:metabolism; D010449:Peptide Mapping; D011485:Protein Binding; D017510:Protein Folding; D017433:Protein Structure, Secondary; D017434:Protein Structure, Tertiary; D013884:Thiosulfate Sulfurtransferase / Q000737:chemistry
D018834:Chaperonin 60; D046911:Macromolecular Substances; D010446:Peptide Fragments; D013884:Thiosulfate Sulfurtransferase; D018833:Chaperonins