title: GroES and the chaperonin-assisted protein folding cycle: GroES has no affinity for nucleotides.
abstract: The E. coli chaperonin proteins, GroEL and GroES, assist in folding newly synthesized proteins. GroES is necessary for GroEL-assisted folding under conditions where the substrate protein cannot spontaneously fold. On the basis of photolabelling of GroES with 8-azido-ATP, a role for nucleotide binding to GroES in chaperonin function was suggested [Martin, et al., Nature, 366 (1993) 279-282]. We confirm the photolabeling of GroES with 8-azido-ATP. However, other proteins not known to contain nucleotide binding sites also became photolabeled suggesting that labeling is non-specific. Using rigorous physical methods, isothermal calorimetry and equilibrium binding, no interaction between GroES and nucleotides could be detected. We conclude that GroES has no nucleotide binding site.
authors.affiliation: Dupont Co. Experimental Station, Central Research and Development Department, Wilmington, DE 19880-0402.
authors.forename: M J
authors.initials: MJ
authors.lastname: Todd
authors.forename: O
authors.initials: O
authors.lastname: Boudkin
authors.forename: E
authors.initials: E
authors.lastname: Freire
authors.forename: G H
authors.initials: GH
authors.lastname: Lorimer
mesh_terms: D000255:Adenosine Triphosphate / Q000031:analogs & derivatives / Q000378:metabolism; D000345:Affinity Labels; D001386:Azides; D001665:Binding Sites; D018835:Chaperonin 10 / Q000378:metabolism*; D009711:Nucleotides / Q000378:metabolism*; D017510:Protein Folding; D013816:Thermodynamics
chemical_list: D000345:Affinity Labels; D001386:Azides; D018835:Chaperonin 10; D009711:Nucleotides; C017040:8-azidoadenosine 5'-triphosphate; D000255:Adenosine Triphosphate