Pressure- and temperature-induced unfolding and aggregation of recombinant human interferon-gamma: a Fourier transform infrared spectroscopy study.
The effect of hydrostatic pressure on the secondary structure of recombinant human interferon-gamma (rhIFN-gamma) and its biologically inactive truncated form rhIFN-Delta C15 has been studied using Fourier-transform IR (FTIR) spectroscopy. In situ observation of the pressure-induced changes using the diamond anvil cell shows that the alpha-helical structure is mainly transformed into disordered structure at high pressure. Increasing pressure also induces the formation of a gel. Addition of 0.5 M MgCl(2) significantly reduces the pressure stability. Releasing the pressure below 300 MPa results in the formation of intermolecular antiparallel beta-sheets, which is seldom observed. This suggests that the intermolecular beta-sheet of rhIFN-gamma is stabilized by electrostatic interactions that are disrupted at high pressure. For comparison we also studied the effect of temperature. Temperature-induced changes reflect extensive transformation of alpha-helical structure into intermolecular antiparallel beta-sheet, as is usually observed for most proteins.
Goossens
Koen
K
Laboratorium voor Chemische en Biologische Dynamica, Celestijnenlaan 200 D, B-3001 Leuven, Belgium.
Haelewyn
Joost
J
Meersman
Filip
F
De Ley
Marc
M
Heremans
Karel
K
D006358:Hot Temperature; D006801:Humans; D007371:Interferon-gamma / Q000737:chemistry*; D011312:Pressure; D011489:Protein Denaturation; D011994:Recombinant Proteins / Q000737:chemistry; D017550:Spectroscopy, Fourier Transform Infrared
D011994:Recombinant Proteins; D007371:Interferon-gamma