Structural evolution of the chromophore in the primary stages of trans/cis isomerization in photoactive yellow protein.

ABSTRACT: We have studied the structural changes induced by optical excitation of the chromophore in wild-type photoactive yellow protein (PYP) in liquid solution with a combined approach of polarization-sensitive ultrafast infrared spectroscopy and density functional theory calculations. We identify the nuC8-C9 marker modes for solution phase PYP in the P and I0 states, from which we derive that the first intermediate state I0 that appears with a 3 ps time constant can be characterized to have a cis geometry. This is the first unequivocal demonstration that the formation of I0 correlates with the conversion from the trans to the cis state. For the P and I0 states we compare the experimentally measured vibrational band patterns and anisotropies with calculations and find that for both trans and cis

SUBMITTER: Heyne K 

PROVIDER: S-EPMC2580759 | biostudies-literature | 2005 Dec

REPOSITORIES: biostudies-literature