title: Conversion of the allosteric transition of GroEL from concerted to sequential by the single mutation Asp-155 -> Ala.
abstract: The reaction cycle of the double-ring chaperonin GroEL is driven by ATP binding that takes place with positive cooperativity within each seven-membered ring and negative cooperativity between rings. The positive cooperativity within rings is due to ATP binding-induced conformational changes that are fully concerted. Herein, it is shown that the mutation Asp-155 --> Ala leads to an ATP-induced break in intra-ring and inter-ring symmetry. Electron microscopy analysis of single-ring GroEL particles containing the Asp-155 --> Ala mutation shows that the break in intra-ring symmetry is due to stabilization of allosteric intermediates such as one in which three subunits have switched their conformation while the other four have not. Our results show that eliminating an intra-subunit interaction between Asp-155 and Arg-395 results in conversion of the allosteric switch of GroEL from concerted to sequential, thus demonstrating that its allosteric behavior arises from coupled tertiary conformational changes.
authors: Department of Structural Biology, Weizmann Institute of Science, Rehovot 76100, Israel.
authors: Oded
authors: O
authors: Danziger
authors: Dalia
authors: D
authors: Rivenzon-Segal
authors: Sharon G
authors: SG
authors: Wolf
authors: Amnon
authors: A
authors: Horovitz
mesh_terms: D000255:Adenosine Triphosphate / Q000378:metabolism; D000494:Allosteric Regulation; D000495:Allosteric Site / Q000235:genetics; D019943:Amino Acid Substitution; D001483:Base Sequence; D018834:Chaperonin 60 / Q000737:chemistry* / Q000235:genetics* / Q000378:metabolism; D004269:DNA, Bacterial / Q000235:genetics; D007700:Kinetics; D008854:Microscopy, Electron; D008958:Models, Molecular; D016297:Mutagenesis, Site-Directed; D017434:Protein Structure, Tertiary; D021122:Protein Subunits
chemical_list: D018834:Chaperonin 60; D004269:DNA, Bacterial; D021122:Protein Subunits; D000255:Adenosine Triphosphate