The color tuning mechanism of the rhodopsin protein family has been in the focus of research for decades. However, the structural basis of the tuning mechanism in general and of the absorption shift between rhodopsins in particular remains under discussion. It is clear that a major determinant for spectral shifts between different rhodopsins are electrostatic interactions between the chromophor...

The dynamics of bacteriorhodopsin (bR) and the lipid headgroups in oriented purple membranes (PMs) was determined at various temperatures and relative humidity (rh) using solid-state NMR spectroscopy. The 31P NMR spectra of the alpha- and gamma-phosphate groups in methyl phosphatidylglycerophosphate (PGP-Me), which is the major phospholipid in the PM, changed sensitively with hydration levels. ...

Herein, the absorption maximum of bacteriorhodopsin (bR) is calculated using our recently developed method in which the whole protein can be treated quantum mechanically at the level of INDO/S-CIS//ONIOM (B3LYP/6-31G(d,p): AMBER). The full quantum mechanical calculation is shown to reproduce the so-called opsin shift of bR with an error of less than 0.04 eV. We also apply the same calculation f...

Bacteriorhodopsin has been proved to be an outstanding candidate for reversible, transient, real-time, holographic material. Here we show our preliminary experimental investigation of its applicability as a transient analog memory, concentrating on its possible utilization in optical CNN implementations and in programmable opto-electronic analogic CNN computers (POAC). Different possible archit...

Reaction-induced infrared difference spectra show characteristic amide I spectral changes, which indicate conformational changes of the protein backbone but which cannot be interpreted at a molecular level. To obtain some insights into their causes, we used bacteriorhodopsin as a model system and investigated its BR f N transition during which the largest amide I changes are observed. For the m...

This article views predominately the structure and function of animal and bacterial photoreceptor pigments (rhodopsin, iodopsin, bacteriorhodopsin) and their nanoand biotechnological usage. On an example of bacterial pigment bacteriorhodopsin (BR) is described the method of its isolation from purple membranes of halophilic bacterium Halobacterium halobium by cellular autolysis by distilled wate...

Phototaxis and photophobic responses of green algae are mediated by rhodopsins with microbial type chromophores, i.e. all-trans-retinal in the ground state. The green alga Chlamydomonas reinhardtii was recently completely sequenced and the EST (expressed sequence tag) database was made public. We and others detected overlapping partial cDNA sequences that encode two proteins which we termed cha...

Nanoscale sensing arrays utilizing the unique properties of the optical protein bacteriorhodopsin and colloidal semiconductor quantum dots are being developed for toxin detection applications. This paper describes an innovative method to activate bacteriorhodopsin-based electrodes with the optical output of quantum dots, producing an enhanced electrical response from the protein. Results show t...

This study has used chemical modification techniques to investigate the role of the only two types of positively charged amino acids, lysines and arginines, in the membrane-bound protein, bacteriorhodopsin (bR)• The results of these chemical modifications have significance both for the structure of bR and for the molecular mechanism of light-activated photocycling and proton pumping. The implic...

Metal cations are known to be required for proton pumping by bacteriorhodopsin (bR). Previous studies found that bR has two high-affinity and four to six low-affinity Ca(2+)-binding sites. In our efforts to find the location of these Ca2+ sites, the effects of replacing charged (Asp-85, Asp-212, and Arg-82) and H-bonding (Tyr-185) residues in the retinal pocket on the color control and binding ...