title: Primary steps of the photoactive yellow protein: isolated chromophore dynamics and protein directed function.
abstract: The cycle of the photoactive yellow protein (PYP) has been extensively studied, but the dynamics of the isolated chromophore responsible for transduction is unknown. Here, we present real-time observation of the dynamics of the negatively charged chromophore and detection of intermediates along the path of trans-to-cis isomerization using femtosecond mass selection/electron detachment techniques. The results show that the role of the protein environment is not in the first step of double-bond twisting (barrier crossing) but in directing efficient conversion to the cis-structure and in impeding radical formation within the protein.
authors.affiliation: Arthur Amos Noyes Laboratory of Chemical Physics, Laboratory for Molecular Sciences, California Institute of Technology, Pasadena, CA 91125, USA.
authors.forename: I-Ren
authors.initials: IR
authors.lastname: Lee
authors.forename: Wonchul
authors.initials: W
authors.lastname: Lee
authors.forename: Ahmed H
authors.initials: AH
authors.lastname: Zewail
mesh_terms: D001426:Bacterial Proteins / Q000737:chemistry* / Q000378:metabolism*; D003116:Color; D020607:Halorhodospira halophila / Q000737:chemistry*; D008958:Models, Molecular; D010777:Photochemistry; D017434:Protein Structure, Tertiary; D013057:Spectrum Analysis
chemical_list: D001426:Bacterial Proteins