title: Differential conformational modulations of MreB folding upon interactions with GroEL/ES and TRiC chaperonin components.
abstract: Here, we study and compare the mechanisms of action of the GroEL/GroES and the TRiC chaperonin systems on MreB client protein variants extracted from E. coli. MreB is a homologue to actin in prokaryotes. Single-molecule fluorescence correlation spectroscopy (FCS) and time-resolved fluorescence polarization anisotropy report the binding interaction of folding MreB with GroEL, GroES and TRiC. Fluorescence resonance energy transfer (FRET) measurements on MreB variants quantified molecular distance changes occurring during conformational rearrangements within folding MreB bound to chaperonins. We observed that the MreB structure is rearranged by a binding-induced expansion mechanism in TRiC, GroEL and GroES. These results are quantitatively comparable to the structural rearrangements found during the interaction of β-actin with GroEL and TRiC, indicating that the mechanism of chaperonins is conserved during evolution. The chaperonin-bound MreB is also significantly compacted after addition of AMP-PNP for both the GroEL/ES and TRiC systems. Most importantly, our results showed that GroES may act as an unfoldase by inducing a dramatic initial expansion of MreB (even more than for GroEL) implicating a role for MreB folding, allowing us to suggest a delivery mechanism for GroES to GroEL in prokaryotes.
authors.affiliation: CNRS, Aix Marseille Université, Centrale Marseille, Institut Fresnel, 13013 Marseille, France.
authors.forename: Satish Babu
authors.initials: SB
authors.lastname: Moparthi
authors.affiliation: IFM, Department of Chemistry, Linköping University, 581 83 Linköping, Sweden.
authors.forename: Uno
authors.initials: U
authors.lastname: Carlsson
authors.affiliation: Architecture et Fonction des Macromolécules Biologiques (A.F.M.B), UMR7257 CNRS, Université Aix-Marseille, Case 932, 163 Avenue de Luminy, 13288 Marseille Cedex 9, France.
authors.forename: Renaud
authors.initials: R
authors.lastname: Vincentelli
authors.affiliation: IFM, Department of Chemistry, Linköping University, 581 83 Linköping, Sweden.
authors.forename: Bengt-Harald
authors.initials: BH
authors.lastname: Jonsson
authors.affiliation: IFM, Department of Chemistry, Linköping University, 581 83 Linköping, Sweden.
authors.forename: Per
authors.initials: P
authors.lastname: Hammarström
authors.affiliation: CNRS, Aix Marseille Université, Centrale Marseille, Institut Fresnel, 13013 Marseille, France.
authors.forename: Jérôme
authors.initials: J
authors.lastname: Wenger
mesh_terms: D000199:Actins / Q000378:metabolism; D018835:Chaperonin 10 / Q000378:metabolism*; D018834:Chaperonin 60 / Q000378:metabolism*; D056404:Chaperonin Containing TCP-1 / Q000378:metabolism*; D004926:Escherichia coli / Q000235:genetics / Q000378:metabolism*; D029968:Escherichia coli Proteins / Q000737:chemistry* / Q000235:genetics / Q000378:metabolism*; D031541:Fluorescence Resonance Energy Transfer; D008958:Models, Molecular; D009154:Mutation; D011485:Protein Binding; D011487:Protein Conformation; D017510:Protein Folding; D017434:Protein Structure, Tertiary; D000072760:Single Molecule Imaging
chemical_list: D000199:Actins; D018835:Chaperonin 10; D018834:Chaperonin 60; D029968:Escherichia coli Proteins; C078473:MreB protein, E coli; D056404:Chaperonin Containing TCP-1