Effect of dynamic high pressure on the secondary structure of beta-lactoglobulin and on its conformational properties as determined by Fourier transform infrared spectroscopy

摘要

The effect of dynamic high pressure on the conformation of beta-lactoglobulin (BLG) was studied using Fourier-transform infrared spectroscopy. The results show that, whatever the pressure used (range 0-1400 bar), the conformation-sensitive amide-I band showed the maximum absorption at around 1636 cm-1 proving that the beta-sheet was the major structural element. The location of other amide-I component bands was very close in this pressure range, suggesting that dynamic high pressure had practicallyno effect on the secondary structure of BLG. However, there were 3 critical differences between treated and untreated BLG: (i) a different pH sensitivity, (ii) a different thermostability with treated BLG being thermally more stable than untreated BLG,and (iii) different behaviour during the cooling regime of the thermal gelation process. These results suggest that, despite having a similar overall conformation, the architecture of BLG before and after dynamic high pressure is stabilized by slightly different interactions.