[NMR paper] Formation of the chaperonin complex studied by 2D NMR spectroscopy.

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Formation of the chaperonin complex studied by 2D NMR spectroscopy.

Related Articles Formation of the chaperonin complex studied by 2D NMR spectroscopy.

PLoS One. 2017;12(10):e0187022

Authors: Takenaka T, Nakamura T, Yanaka S, Yagi-Utsumi M, Chandak MS, Takahashi K, Paul S, Makabe K, Arai M, Kato K, Kuwajima K

Abstract
We studied the interaction between GroES and a single-ring mutant (SR1) of GroEL by the NMR titration of 15N-labeled GroES with SR1 at three different temperatures (20, 25 and 30°C) in the presence of 3 mM ADP in 100 mM KCl and 10 mM MgCl2 at pH 7.5. We used SR1 instead of wild-type double-ring GroEL to precisely control the stoichiometry of the GroES binding to be 1:1 ([SR1]:[GroES]). Native heptameric GroES was very flexible, showing well resolved cross peaks of the residues in a mobile loop segment (residue 17-34) and at the top of a roof hairpin (Asn51) in the heteronuclear single quantum coherence spectra. The binding of SR1 to GroES caused the cross peaks to disappear simultaneously, and hence it occurred in a single-step cooperative manner with significant immobilization of the whole GroES structure. The binding was thus entropic with a positive entropy change (219 J/mol/K) and a positive enthalpy change (35 kJ/mol), and the binding constant was estimated at 1.9×105 M-1 at 25°C. The NMR titration in 3 mM ATP also indicated that the binding constant between GroES and SR1 increased more than tenfold as compared with the binding constant in 3 mM ADP. These results will be discussed in relation to the structure and mechanisms of the chaperonin GroEL/GroES complex.


PMID: 29059240 [PubMed - indexed for MEDLINE]



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