title: Ligands regulate GroEL thermostability.
abstract: Escherichia coli heat-shock proteins GroEL and GroES stimulate (in an ATP-dependent manner) the folding of various proteins. In this study scanning microcalorimetry was applied to investigate GroEL thermostability in the presence of its ligands. Mg2+ and K+ ions stabilize while ADP destabilizes the GroEL molecule against the action of temperature. Furthermore, ADP essentially increases the number of binding sites for the hydrophobic probe (ANS) and the number of GroEL SH-groups accessible to Ellman's reagent as well as the accessibility of the protein to the action of trypsin. The interaction of GroEL with GroES in the presence of Mg2+-ADP eliminates the destabilizing effect of ADP on the GroEL molecule against the action of temperature and Ellman's reagent but does not change its hydrophobicity and accessibility to trypsin.
authors.affiliation: Institute of Protein Research, Russian Academy of Sciences, Moscow Region, Russian Federation.
authors.forename: A K
authors.initials: AK
authors.lastname: Surin
authors.forename: N V
authors.initials: NV
authors.lastname: Kotova
authors.forename: I A
authors.initials: IA
authors.lastname: Kashparov
authors.forename: V V
authors.initials: VV
authors.lastname: Marchenkov
authors.lastname: Marchenkova SYu
authors.forename: G V
authors.initials: GV
authors.lastname: Semisotnov
mesh_terms: D000244:Adenosine Diphosphate / Q000737:chemistry; D002152:Calorimetry, Differential Scanning; D018835:Chaperonin 10 / Q000737:chemistry; D018834:Chaperonin 60 / Q000737:chemistry*; D004926:Escherichia coli; D006358:Hot Temperature; D008024:Ligands; D011487:Protein Conformation; D011489:Protein Denaturation; D012996:Solutions; D013816:Thermodynamics; D014357:Trypsin / Q000378:metabolism
chemical_list: D018835:Chaperonin 10; D018834:Chaperonin 60; D008024:Ligands; D012996:Solutions; D000244:Adenosine Diphosphate; D014357:Trypsin