Pressure-induced protein unfolding in the ternary system AOT-octane-water is different from that in bulk water

Forskningsoutput: TidskriftsbidragArtikel i vetenskaplig tidskrift

Abstract

In a cellular environment, the presence of macromolecular cosolutes and membrane interfaces can influence the folding-unfolding behavior of proteins. Here we report on the pressure stability of alpha-chymotrypsin in the ternary system bis(2-ethylhexyl)sodium sulfosuccinate-octane-water using FTIR spectroscopy. The ternary system forms anionic reverse micelles which mimic cellular conditions. We find that inclusion of a single protein molecule in a reverse micelle does not alter its conformation. When pressurized in bulk water, alpha-chymotrypsin unfolds at 750 MPa into a partially unfolded structure. In contrast, in the ternary system, the same pressure increase induces a random coil-like unfolded state, which collapses into an amorphous aggregate during the decompression phase. It is suggested that the unfolding pathway is different in a cell-mimicking environment due to the combined effect of multiple factors, including confinement. A phase transition of the reverse micellar to the lamellar phase is thought to be essential to provide the conditions required for unfolding and aggregation, though the unfolding is not a direct result of the phase transition. Our observations therefore suggest that membranes may cause the formation of alternative conformations that are more susceptible to aggregation.

Detaljer

Författare
  • F Meersman
  • C Dirix
  • Stepan Shipovskov
  • N L Klyachko
  • K Heremans
Enheter & grupper
Forskningsområden

Ämnesklassifikation (UKÄ) – OBLIGATORISK

  • Biologiska vetenskaper
Originalspråkengelska
Sidor (från-till)3599-3604
TidskriftLangmuir
Volym21
Utgåva nummer8
StatusPublished - 2005
PublikationskategoriForskning
Peer review utfördJa