Voltage Imaging with Engineered Proton-Pumping Rhodopsins: Insights from the Proton Transfer Pathway

Voltage-gated proton channels and other proton transfer pathways.

Proton channels exist in a wide variety of membrane proteins where they transport protons rapidly and efficiently. Usually the proton pathway is formed mainly by water molecules present in the protein, but its function is regulated by titratable groups on critical amino acid residues in the pathway. All proton channels conduct protons by a hydrogen-bonded chain mechanism in which the proton hop...

Chimeric Proton-Pumping Rhodopsins Containing the Cytoplasmic Loop of Bovine Rhodopsin

G-protein-coupled receptors (GPCRs) transmit stimuli to intracellular signaling systems. Rhodopsin (Rh), which is a prototypical GPCR, possesses an 11-cis retinal. Photoisomerization of 11-cis to all-trans leads to structural changes in the protein of cytoplasmic loops, activating G-protein. Microbial rhodopsins are similar heptahelical membrane proteins that function as bacterial sensors, ligh...

Proton Pumping P Systems

We propose here a (biologically inspired) model of P system called proton pumping P system that is a special case of evolution– communication P system. In cell biology there are transport mechanisms, involving protons. We generalize this idea by considering a few different types of protons. A proton pumping P system is, essentially, an evolution–communication P system where a special subset of ...

Photo-Induced Proton Transfers of Microbial Rhodopsins

Intermolecular proton shuttling in excited state proton transfer reactions: insights from theory.

The mechanism of base to base intermolecular proton shuttling occurring in the excited state proton transfer reaction between 7-hydroxy-4-(trifluoromethyl)coumarin (CouOH) and concentrated 1-methylimidazole base (1-MeId) in toluene solution is disclosed here by means of a computational approach based on Density Functional Theory (DFT) and Time Dependent DFT (TD-DFT). These methods allow us to c...