title: NMR analysis of the binding of a rhodanese peptide to a minichaperone in solution.
abstract: A detailed structural analysis of interactions between denatured proteins and GroEL is essential for an understanding of its mechanism. Minichaperones constitute an excellent paradigm for obtaining high-resolution structural information about the binding site and conformation of substrates bound to GroEL, and are particularly suitable for NMR studies. Here, we used transferred nuclear Overhauser effects to study the interaction in solution between minichaperone GroEL(193-335) and a synthetic peptide (Rho), corresponding to the N-terminal alpha-helix (residues 11 to 23) of the mitochondrial rhodanese, a protein whose in vitro refolding is mediated by minichaperones. Using a 60 kDa maltose-binding protein (MBP)-GroEL(193-335) fusion protein to increase the sensitivity of the transferred NOEs, we observed characteristic sequential and mid-range transferred nuclear Overhauser effects. The peptide adopts an alpha-helical conformation upon binding to the minichaperone. Thus the binding site of GroEL is compatible with binding of alpha-helices as well as extended beta-strands. To locate the peptide-binding site on GroEL(193-335), we analysed changes in its chemical shifts on adding an excess of Rho peptide. All residues with significant chemical shift differences are localised in helices H8 and H9. Non-specific interactions were not observed. This indicates that the peptide Rho binds specifically to minichaperone GroEL(193-335). The binding region identified by NMR in solution agrees with crystallographic studies with small peptides and with fluorescence quenching studies with denatured proteins.
authors.affiliation: Cambridge University Chemical Laboratory and MRC Centre for Protein Engineering, Hills Road, Cambridge, CB2 2QH, UK.
authors.forename: N
authors.initials: N
authors.lastname: Kobayashi
authors.forename: S M
authors.initials: SM
authors.lastname: Freund
authors.forename: J
authors.initials: J
authors.lastname: Chatellier
authors.forename: R
authors.initials: R
authors.lastname: Zahn
authors.forename: A R
authors.initials: AR
authors.lastname: Fersht
mesh_terms: D018528:ATP-Binding Cassette Transporters; D000595:Amino Acid Sequence; D000818:Animals; D001665:Binding Sites; D002352:Carrier Proteins / Q000737:chemistry; D002417:Cattle; D018834:Chaperonin 60 / Q000737:chemistry*; D004926:Escherichia coli; D029968:Escherichia coli Proteins; D009682:Magnetic Resonance Spectroscopy; D058619:Maltose-Binding Proteins; D008958:Models, Molecular; D018832:Molecular Chaperones / Q000737:chemistry*; D008969:Molecular Sequence Data; D009004:Monosaccharide Transport Proteins; D010446:Peptide Fragments / Q000737:chemistry*; D011485:Protein Binding; D011489:Protein Denaturation; D017433:Protein Structure, Secondary; D011993:Recombinant Fusion Proteins / Q000737:chemistry; D013884:Thiosulfate Sulfurtransferase / Q000737:chemistry*
chemical_list: D018528:ATP-Binding Cassette Transporters; D002352:Carrier Proteins; D018834:Chaperonin 60; D029968:Escherichia coli Proteins; D058619:Maltose-Binding Proteins; D018832:Molecular Chaperones; D009004:Monosaccharide Transport Proteins; D010446:Peptide Fragments; D011993:Recombinant Fusion Proteins; C461599:maltose transport system, E coli; D013884:Thiosulfate Sulfurtransferase