Optimization of expression and purification of mitochondrial HSP 40 (Tid1-L) chaperone: Role of mortalin and tid1 in the reactivation and amyloid inhibition of proteins.

Stimulation of complex chaperone activity may be a viable means of therapy for neurodegenerative diseases. These chaperons execute reactivation of thermally and chemically aggregated protein substrates by cooperating with their partner co-chaperons. We optimized the expression and purification conditions of Tid1-L chaperone. Expression of Tid1-L in E. coli resulted in the formation of inclusion bodies which was further purified to soluble active form using 8 M urea and Ni-NTA column. Also, we investigated the events of the reactivation and disaggregation using aggregated G6PDH, luciferase and insulin as substrates. Incubation of aggregated/denatured enzymes with mortalin but not with Tid1 and/or Mge1 resulted in the initiation of the disaggregation reaction albeit very insignificantly. Under the same conditions coincubating the samples with chaperon and its assisted partners Tidl-L and nucleotide exchange factor Mge1 led to (40%) increase in enzyme activity of G6PDH. Similarly, luciferase activity was syner-gistically enhanced in the presence of mortlain/Tid1-L/Mgel chaperones machinery. Chaperone-dependent disaggregation of thermally aggregated insulin showed that addition of Hsp70 and Hsp40 chaperones resulted in fast-track of renaissance reaction and inhibition of amyloid. The present study results conclude the quality of cell-control involves interaction of chaperon Hsp70 and its cochaperones leading to complex formation with chemically/thermally aggregated substrate eventually causing its reactivation and disaggregation. (C) 2020 Published by Elsevier B.V. on behalf of King Saud University.