title: Thermal denaturation and aggregation of apoform of glycogen phosphorylase b. Effect of crowding agents and chaperones.
abstract: The effect of protein and chemical chaperones and crowders on thermal stability and aggregation of apoform of rabbit muscle glycogen phosphorylase b (apoPhb) has been studied at 37°C. Proline suppressed heat-induced loss in ability of apoPhb to reconstitution at 37°C, whereas α-crystallin did not reveal a protective action. To compare the antiaggregation activity of intact and crosslinked α-crystallins, an adsorption capacity (AC) of a protein chaperone with respect to a target protein was estimated. This parameter is a measure of the antiaggregation activity. Crosslinking of α-crystallin results in 11-fold decrease in the initial AC. The nonlinear character of the relative initial rate of apoPhb aggregation versus the [intact α-crystallin]/[apoPhb] ratio plot is indicative of the decrease in the AC of α-crystallin with increasing the [α-crystallin]/[apoPhb] ratio and can be interpreted as an evidence for dynamic chaperone structure and polydispersity of α-crystallin-target protein complexes. As for chemical chaperones, a semisaturation concentration of the latter was used as a characteristic of the antiaggregation activity. A decrease in the semisaturation concentration for proline was observed in the presence of the crowders (polyethylene glycol and Ficoll-70).
authors.affiliation: Department of Structural Biochemistry of Proteins, A.N. Bach Institute of Biochemistry, Russian Academy of Sciences, Leninsky Prospect 33, Moscow, 119071, Russia.
authors.forename: Tatyana B
authors.initials: TB
authors.lastname: Eronina
authors.forename: Natalia A
authors.initials: NA
authors.lastname: Chebotareva
authors.forename: Svetlana G
authors.initials: SG
authors.lastname: Roman
authors.forename: Sergey Yu
authors.initials: SY
authors.lastname: Kleymenov
authors.forename: Valentina F
authors.initials: VF
authors.lastname: Makeeva
authors.forename: Nikolay B
authors.initials: NB
authors.lastname: Poliansky
authors.forename: Konstantin O
authors.initials: KO
authors.lastname: Muranov
authors.forename: Boris I
authors.initials: BI
authors.lastname: Kurganov
mesh_terms: D000818:Animals; D001059:Apoproteins / Q000378:metabolism*; D019540:Area Under Curve; D002417:Cattle; D003432:Cross-Linking Reagents / Q000494:pharmacology; D006358:Hot Temperature; D007700:Kinetics; D046911:Macromolecular Substances / Q000494:pharmacology*; D018832:Molecular Chaperones / Q000494:pharmacology*; D010763:Phosphorylase b / Q000378:metabolism*; D011092:Polyethylene Glycols / Q000494:pharmacology; D011392:Proline / Q000494:pharmacology; D066329:Protein Aggregates / Q000187:drug effects*; D011489:Protein Denaturation / Q000187:drug effects*; D011817:Rabbits; D038201:alpha-Crystallins / Q000494:pharmacology
chemical_list: D001059:Apoproteins; D003432:Cross-Linking Reagents; D046911:Macromolecular Substances; D018832:Molecular Chaperones; D066329:Protein Aggregates; D038201:alpha-Crystallins; D011092:Polyethylene Glycols; D011392:Proline; D010763:Phosphorylase b
keywords: apoform of glycogen phosphorylase b; chemical chaperones; protein chaperones; thermal aggregation; thermal denaturation