Effects of spermine NONOate and ATP on protein aggregation: light scattering evidences
Background and ObjectiveRegulating protein function in the cell by small molecules, provide a rapid, reversible and tunable tool ofmetabolic control. However, due to its complexity the issue is poorly studied so far.
The effects of smallsolutes on protein behavior can be studied by examining changes of protein secondary structure, in itshydrodynamic radius as well as its thermal aggregation. The study aim was to investigate effects ofadenosine-5'-triphosphate (ATP), spermine NONOate (NO donor) as well as sodium/potassium ions onthermal aggregation of albumin and hemoglobin.
To follow aggregation of the proteins, their diffusioncoefficients were measured by quasi-elastic light scattering (QELS) at constant pH (7.4) in the presence ofsolutes over a temperature range from 25 degreesC to 80 degreesC.Results and discussion1) spermine NONOate persistently decreased the hemoglobin aggregation temperature Ta irrespectively of theNa+/K+ environment, 2) ATP alone had no effect on the protein's thermal stability but it facilitated protein'sdestabilization in the presence of spermine NONOate and 3) mutual effects of ATP and NO were stronglyinfluenced by particular buffer ionic compositions.
The ATP effect on protein aggregation was ambiguous: ATP alone had no effect on the protein's thermalstability but it facilitated protein's destabilization in the presence of nitric oxide. The magnitude and directionof the observed effects strongly depended on concentrations of K+ and Na+ in the solution.
Published on: 2013-01-04