- Addition of salt enhanced thermal stability of model substrate proteins by reducing electrostatic repulsion between protein molecules. - However, the opposite effect was observed with bacterial cell lysate, indicating that certain molecules within the lysate could enhance protein stability via electrostatic interactions. - Such molecules present in cell lysate were found to be nucleic acids known to have a potent anti-aggregation activity toward proteins involving electrostatic interactions. - Nucleic acids showed chaperone activity in physiological salt concentration within cells and in buffer or medium commonly used in experiments. - The chaperone activity of nucleic acids should be taken into account when performing various in vitro assays using cell lysate or samples containing nucleic acids.
Changhan Lee received funding from the National Research Foundation of Korea (NRF) funded by the Korea government (MSIT) (grant 2021R1C1C1011690 and RS- 2023-00217595 ), the Basic Science Research Program through the NRF funded by the Ministry of Education (grant 2021R1A6A1A10044950 ) and the new faculty research fund of Ajou University.