Mutation Ala2-->Ser destabilizes intersubunit interactions in the molecular chaperone GroEL.
The mutation Ala2-->Ser in the molecular chaperone GroEL increases positive co-operativity in ATP hydrolysis, as reflected by a change in the Hill coefficient from 2.36(+/- 0.23) for wild-type to 3.19(+/- 0.17) for the mutant. This amino acid replacement destabilizes the oligomeric structure of GroEL. It is shown that adenine nucleotides also have a specific destabilizing effect which is more pronounced in the case of the Ala2-->Ser mutant. Addition of GroES or the non-folded protein ligand rhodanese blocks the destabilizing effect of adenine nucleotides for both wild-type and mutant. The results are interpreted using the Monod-Wyman-Changeux (MWC) model for co-operativity.
Horovitz
A
A
Department of Structural Biology, Weizmann Institute of Science, Rehovot, Israel.
Bochkareva
E S
ES
Kovalenko
O
O
Girshovich
A S
AS
D000251:Adenosine Triphosphatases / Q000235:genetics / Q000378:metabolism; D000409:Alanine; D000595:Amino Acid Sequence; D001426:Bacterial Proteins / Q000235:genetics* / Q000378:metabolism*; D001483:Base Sequence; D018835:Chaperonin 10; D018834:Chaperonin 60; D004926:Escherichia coli / Q000235:genetics*; D006360:Heat-Shock Proteins / Q000235:genetics* / Q000378:metabolism*; D007700:Kinetics; D046911:Macromolecular Substances; D008954:Models, Biological; D008969:Molecular Sequence Data; D016297:Mutagenesis, Site-Directed; D009838:Oligodeoxyribonucleotides; D012265:Ribonucleotides / Q000494:pharmacology; D012694:Serine
D001426:Bacterial Proteins; D018835:Chaperonin 10; D018834:Chaperonin 60; D006360:Heat-Shock Proteins; D046911:Macromolecular Substances; D009838:Oligodeoxyribonucleotides; D012265:Ribonucleotides; D012694:Serine; D000251:Adenosine Triphosphatases; D000409:Alanine