Decay constant first excitation state K of proteorhodopsin

Range 2-20 psec
Organism Unspecified
Reference Rupenyan A, van Stokkum IH, Arents JC, van Grondelle R, Hellingwerf K, Groot ML. Characterization of the primary photochemistry of proteorhodopsin with femtosecond spectroscopy. Biophys J. 2008 May 1594(10):4020-30.PubMed ID18234812
Method Femtosecond time-resolved spectroscopy, by probing in the visible- and in the midinfrared spectral regions.
Comments From the difference spectra associated with these dynamics, researchers conclude that there are two chromophore-isomerization pathways that lead to the K-state: one with an effective rate of approximately (2 ps)(-1) and the other with a rate of approximately (20 ps)(-1). At high pH (9.5), both pathways are equally effective, with an estimated quantum yield for K-formation of approximately 0.7. At pH 6.5, the slower pathway is less productive, which results in an isomerization quantum yield of 0.5.
Entered by Uri M
ID 103608