Hexafluoroisopropanol-induced helix–sheet transition of stem bromelain: Correlation to function

摘要: Stem bromelain is a proteolytic phytoprotein with variety of therapeutic effects. Understanding its structural properties could provide insight into the mechanisms underlying clinical utility. was evaluated for conformational and folding at pH conditions it encounters when administered orally. It exists as partially folded intermediate 2.0. The changes to this state were using fluorinated alcohols known induce similar those seen in vivo. Studies circular dichroism, fluorescence emission spectroscopy, binding hydrophobic dye 1-anilino-8-naphthalene sulfonic acid mass spectrometry indicate that treatment 10-30% hexafluoroisopropanol induces adopt much native protein's secondary structure, but only rudimentary tertiary characteristic molten globule state. Addition slightly higher concentrations caused transformation from an alpha-helix beta-sheet induced formation compact nonnative structure. This form more inhibitory cell survival than either or forms, measured by enhanced suppression proliferative cues (e.g., extracellular-signal-regulated kinase) initiation apoptotic events. also showed better antitumorigenic properties, two-stage mouse skin papilloma model. In contrast, fraction activity form. study demonstrates can change stem potentially useful different protein.