Protein folding at extreme temperatures: Current issues

Abstract

The range of temperatures compatible with life is currently estimated from -25°C, as exemplified by metabolically active bacteria between sea ice crystals, and up to 122°C in hydrothermal vents as exemplified by the archaeon Methanopyrus kandleri. In the context of protein folding, as soon as a polypeptide emerges from the ribosome, it is exposed to the effects of environmental temperatures. Recent investigations have shown that the rate of protein folding is not adapted to extreme temperatures and should be very fast at high temperature and low in cold environments. This lack of adaptation is driven by kinetic constraints on protein stability. To counteract the deleterious effects of fast protein folding in hyperthermophiles, chaperones such as the Trigger Factor hold and slow down the rate of folding intermediates. Prolyl isomerization, a rate-limiting step in the folding of many proteins, is strongly temperature-dependent and impairs folding of psychrophilic proteins in the cold. This is compensated by reduction of the proline content in cold-adapted proteins, by an increased number of prolyl isomerases encoded in the genome of psychrophilic microorganisms and by overexpression of prolyl isomerases under low temperature cultivation. After folding, the native state is reached and although extremophilic proteins share the same fold, dramatic differences in stability have been recorded by differential scanning calorimetry.

Dual-Family Peptidylprolyl Isomerases (Immunophilins) of Select Monocellular Organisms

“…There is ample evidence that binding of partner subunits, and even small molecule ligands, cofactors and ions, often stabilize a protein from denaturation and proteasomal degradation [35,36,37,38]. It is also known that molecular chaperones from bacteria to man protect cellular proteins from denaturation under stress conditions [39,40,41,42]. It is, therefore, quite likely that the DFPPIs mediate a similar effect by facilitating oligomerization.…”

Combined Methylome, Transcriptome and Proteome Analyses Document Rapid Acclimatization of a Bacterium to Environmental Changes

“…Proteins generally contain trans configuration peptide linkages except proline amino acid, which exists in a cis configuration (Joseph et al, 2012). Therefore, prolyl isomerization is a rate-limiting step during protein folding, which is additionally affected by extreme temperatures leading to potential impaired folding during cold (Feller, 2018). Such mis-folding is avoided by PPIases, which help microbes to adapt to low temperature (Budiman et al, 2011).…”

Dual-Family Peptidylprolyl Isomerases (Immunophilins) of Select Monocellular Organisms

“…There is ample evidence that binding of partner subunits, and even small molecule ligands, cofactors, and ions often stabilize a protein from denaturation and proteasomal degradation [32][33][34][35]. It is also known that molecular chaperones from bacteria to man protect cellular proteins from denaturation under stress conditions [36][37][38][39]. It is, therefore, quite likely that the DFPPIs mediate a similar effect by facilitating oligomerization.…”