Unfolding of β-Sheet Proteins in SDS

摘要: β-Sheet proteins are particularly resistant to denaturation by sodium dodecyl sulfate (SDS). Here we compare unfolding of two β-sandwich TNfn3 and TII27 in SDS. The show different surface electrostatic potential. Correspondingly, unfolds below the critical micelle concentration via formation hemimicelles on protein surface, whereas only around concentration. Isothermal titration calorimetry confirms that sets at lower SDS concentrations, although total number bound molecules is similar end unfolding. In mixed micelles with nonionic detergent maltoside, where monomeric insignificant, behavior converges. more slowly than follows a two-mode behavior. Additionally shows inhibition intermediate concentrations. Mutagenic analysis suggests overall mechanism observed denaturant for both proteins. Our data confirm kinetic robustness β-sheet toward We suggest this related inability induce significant amounts α-helix structure these as part process, forcing denature global rather local