Destabilised mutants of ubiquitin gain equal stability in crowded solutions.


This paper investigates the thermodynamic and kinetic response of WT* ubiquitin (F45W) and three mutants to high concentrations of glucose, sucrose and dextran under physiological temperature and pH. WT* ubiquitin was stabilised by the same amount when comparing each cosolute on a weight to volume ratio, with cosolute effects largely independent of denaturant concentration. The energy difference between the mutants and WT* ubiquitin also remained the same in high concentrations of cosolute. An apparent decrease in transition-state surface burial in the presence of the cosolutes was attributed to increased compaction of the denatured state, and not to the Hammond effect. Together, these results suggest higher thermodynamic stabilities and folding rates for proteins in vivo compared to in vitro, in addition to more compact denatured states. Because the effects of mutation are the same in dilute solution and crowded conditions used to mimic the cellular environment, there is validity in using measurements of mutant stabilities made in dilute solutions to inform on how the mutations may affect stability in vivo. Study holds ProTherm entries: 22725, 22726, 22727, 22728, 22729, 22730, 22731, 22732, 22733, 22734, 22735, 22736, 22737, 22738, 22739, 22740, 22741, 22742, 22743, 22744, 22745, 22746, 22747 Extra Details: Pseudo-wild type F45W with a short N-terminal tag; Stability as a function of 0 g/L glucose concentration Ubiquitin; Beta-Tanford value; Glucose; Protein folding; Denatured state

Submission Details

ID: Cmghh5tu

Submitter: Connie Wang

Submission Date: April 24, 2018, 8:53 p.m.

Version: 1

Publication Details
Roberts A;Jackson SE,Biophys. Chem. (2007) Destabilised mutants of ubiquitin gain equal stability in crowded solutions. PMID:17434659
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