Raman spectroscopy reveals direct chromophore interactions in the Leu/Gln105 spectral tuning switch of proteorhodopsins.

ABSTRACT: Proteorhodopsins are an extensive family of photoactive membrane proteins found in proteobacteria distributed throughout the world's oceans which are often classified as green- or blue-absorbing (GPR and BPR, respectively) on the basis of their visible absorption maxima. GPR and BPR have significantly different properties including photocycle lifetimes and wavelength dependence on pH. Previous studies revealed that these different properties are correlated with a single residue, Leu105 in GPR and Gln105 in BPR, although the molecular basis for the different properties of GPR and BPR has not yet been elucidated. We have studied the unexcited states of GPR and BPR using resonance Raman spectroscopy which enhances almost exclusively chromophore vibrations. We find that both spectra are remark

SUBMITTER: Kralj JM 

PROVIDER: S-EPMC3608850 | biostudies-literature | 2008 Sep

REPOSITORIES: biostudies-literature