Isomerization- and temperature-jump-induced dynamics of a photoswitchable β-hairpin.

摘要: Conformational changes in proteins and peptides can be initiated by diverse processes. This raises the question how variation of initiation mechanisms is connected to differences folding or unfolding In this work structural dynamics a photoswitchable β-hairpin model peptide were two different mechanisms: temperature jump (T-jump) isomerization backbone element. both experiments followed time-resolved IR spectroscopy nanosecond microsecond range. When photoisomerization azobenzene switch reaction, pronounced absorption related into hairpin structure found with time constant about 16 μs. T-jump experiment kinetics same observed. For processes reaction revealed strong dependence on temperature. The highly similar transients range show that induced are determined mechanism exclude downhill-folding process. Furthermore, combination techniques allows detailed for presented: isomerization-induced process ends transition-state scheme, which high energetic barrier 48 kJ mol(-1) separates unfolded folded structures.