title: Effect of protein charge on the generation of aggregation-prone conformers.
abstract: This study describes how charge modification affects aggregation of ovalbumin, thereby distinguishing the role of conformational and electrostatic stability in the process. Ovalbumin variants were engineered using chemical methylation or succinylation to obtain a range of protein net charge from -1 to -26. Charge modification significantly affected the denaturation temperature. From urea-induced equilibrium denaturation studies, it followed that unfolding proceeded via an intermediate state. However, the heat-induced denaturation process could still be described as a two-state irreversible unfolding transition, suggesting that the occurrence of an intermediate has no influence on the kinetics of unfolding. By monitoring the aggregation kinetics, the net charge was found not to be discriminative in the process. It is concluded that the dominant factor determining ovalbumin aggregation propensity is the rate of denaturation and not electrostatic repulsive forces.
authors.affiliation: Wageningen Centre for Food Sciences, Diedenweg 20, P.O. Box 557, 6700 AN Wageningen, The Netherlands.
authors.forename: Kerensa
authors.initials: K
authors.lastname: Broersen
authors.forename: Mireille
authors.initials: M
authors.lastname: Weijers
authors.forename: Jolan
authors.initials: J
authors.lastname: de Groot
authors.forename: Rob J
authors.initials: RJ
authors.lastname: Hamer
authors.forename: Harmen H J
authors.initials: HH
authors.lastname: de Jongh
mesh_terms: D000818:Animals; D006358:Hot Temperature; D007700:Kinetics; D010047:Ovalbumin / Q000737:chemistry*; D011489:Protein Denaturation; D017510:Protein Folding; D055672:Static Electricity; D014508:Urea / Q000737:chemistry
chemical_list: D014508:Urea; D010047:Ovalbumin