Click here to close
Hello! We notice that you are using Internet Explorer, which is not supported by Xenbase and may cause the site to display incorrectly.
We suggest using a current version of Chrome,
FireFox, or Safari.
Biophys J
2013 Nov 05;1059:2055-63. doi: 10.1016/j.bpj.2013.08.031.
Show Gene links
Show Anatomy links
Gloeobacter rhodopsin, limitation of proton pumping at high electrochemical load.
Vogt A
,
Wietek J
,
Hegemann P
.
???displayArticle.abstract???
We studied the photocurrents of a cyanobacterial rhodopsin Gloeobacter violaceus (GR) in Xenopus laevis oocytes and HEK-293 cells. This protein is a light-driven proton pump with striking similarities to marine proteorhodopsins, including the D121-H87 cluster of the retinal Schiff base counterion and a glutamate at position 132 that acts as a proton donor for chromophore reprotonation during the photocycle. Interestingly, at low extracellular pH(o) and negative voltage, the proton flux inverted and directed inward. Using electrophysiological measurements of wild-type and mutant GR, we demonstrate that the electrochemical gradient limits outward-directed proton pumping and converts it into a purely passive proton influx. This conclusion contradicts the contemporary paradigm that at low pH, proteorhodopsins actively transport H(+) into cells. We identified E132 and S77 as key residues that allow inward directed diffusion. Substitution of E132 with aspartate or S77 with either alanine or cysteine abolished the inward-directed current almost completely. The proton influx is likely caused by the pK(a) of E132 in GR, which is lower than that of other microbial ion pumping rhodopsins. The advantage of such a low pK(a) is an acceleration of the photocycle and high pump turnover at high light intensities.
Altun,
Quantum mechanical/molecular mechanical studies on spectral tuning mechanisms of visual pigments and other photoactive proteins.
2008, Pubmed
Altun,
Quantum mechanical/molecular mechanical studies on spectral tuning mechanisms of visual pigments and other photoactive proteins.
2008,
Pubmed
Balashov,
Aspartate-histidine interaction in the retinal schiff base counterion of the light-driven proton pump of Exiguobacterium sibiricum.
2012,
Pubmed
Bamberg,
Rhodopsin and other proteins in artificial lipid membranes.
1977,
Pubmed
Béjà,
Bacterial rhodopsin: evidence for a new type of phototrophy in the sea.
2000,
Pubmed
Belkin,
Proton gradients in intact cyanobacteria.
1987,
Pubmed
Bergo,
His-75 in proteorhodopsin, a novel component in light-driven proton translocation by primary pumps.
2009,
Pubmed
Braiman,
A large photolysis-induced pKa increase of the chromophore counterion in bacteriorhodopsin: implications for ion transport mechanisms of retinal proteins.
1996,
Pubmed
Braun,
Nonlinear voltage dependence of the light-driven proton pump current of bacteriorhodopsin.
1988,
Pubmed
Cicirelli,
Internal pH of Xenopus oocytes: a study of the mechanism and role of pH changes during meiotic maturation.
1983,
Pubmed
,
Xenbase
Dioumaev,
Proton transfers in the photochemical reaction cycle of proteorhodopsin.
2002,
Pubmed
Dioumaev,
Proton transport by proteorhodopsin requires that the retinal Schiff base counterion Asp-97 be anionic.
2003,
Pubmed
Drachev,
Direct measurement of electric current generation by cytochrome oxidase, H+-ATPase and bacteriorhodopsin.
1974,
Pubmed
Freier,
Proton transfer via a transient linear water-molecule chain in a membrane protein.
2011,
Pubmed
Friedrich,
Proteorhodopsin is a light-driven proton pump with variable vectoriality.
2002,
Pubmed
,
Xenbase
Geibel,
The voltage-dependent proton pumping in bacteriorhodopsin is characterized by optoelectric behavior.
2001,
Pubmed
,
Xenbase
Gerwert,
Role of aspartate-96 in proton translocation by bacteriorhodopsin.
1989,
Pubmed
Hashimoto,
Low-temperature FTIR study of Gloeobacter rhodopsin: presence of strongly hydrogen-bonded water and long-range structural protein perturbation upon retinal photoisomerization.
2010,
Pubmed
Hempelmann,
His75-Asp97 cluster in green proteorhodopsin.
2011,
Pubmed
Herrmann,
A measurement of the proton pump current generated by bacteriorhodopsin in black lipid membranes.
1976,
Pubmed
Kamikubo,
Structure of the N intermediate of bacteriorhodopsin revealed by x-ray diffraction.
1996,
Pubmed
Lakatos,
The photochemical reaction cycle of proteorhodopsin at low pH.
2003,
Pubmed
Lanyi,
Proton transfers in the bacteriorhodopsin photocycle.
2006,
Pubmed
Lörinczi,
Voltage- and pH-dependent changes in vectoriality of photocurrents mediated by wild-type and mutant proteorhodopsins upon expression in Xenopus oocytes.
2009,
Pubmed
,
Xenbase
Luecke,
Crystallographic structure of xanthorhodopsin, the light-driven proton pump with a dual chromophore.
2008,
Pubmed
Man,
Diversification and spectral tuning in marine proteorhodopsins.
2003,
Pubmed
Marchetti,
Comparative metatranscriptomics identifies molecular bases for the physiological responses of phytoplankton to varying iron availability.
2012,
Pubmed
Michel,
Light-induced changes of the pH gradient and the membrane potential in H. halobium.
1976,
Pubmed
Miranda,
The photocycle and proton translocation pathway in a cyanobacterial ion-pumping rhodopsin.
2009,
Pubmed
Nagel,
Functional expression of bacteriorhodopsin in oocytes allows direct measurement of voltage dependence of light induced H+ pumping.
1995,
Pubmed
,
Xenbase
Nakamura,
Complete genome structure of Gloeobacter violaceus PCC 7421, a cyanobacterium that lacks thylakoids.
2003,
Pubmed
Pace,
Protein ionizable groups: pK values and their contribution to protein stability and solubility.
2009,
Pubmed
Petrovskaya,
Predicted bacteriorhodopsin from Exiguobacterium sibiricum is a functional proton pump.
2010,
Pubmed
Prigge,
Color-tuned channelrhodopsins for multiwavelength optogenetics.
2012,
Pubmed
,
Xenbase
Raven,
Functional evolution of photochemical energy transformations in oxygen-producing organisms.
2009,
Pubmed
Rothschild,
Asp96 deprotonation and transmembrane alpha-helical structural changes in bacteriorhodopsin.
1993,
Pubmed
Schobert,
Crystallographic structure of the K intermediate of bacteriorhodopsin: conservation of free energy after photoisomerization of the retinal.
2002,
Pubmed
Schobert,
Crystallographic structures of the M and N intermediates of bacteriorhodopsin: assembly of a hydrogen-bonded chain of water molecules between Asp-96 and the retinal Schiff base.
2003,
Pubmed
Stoeckenius,
Photoreactions of bacteriorhodopsin.
1977,
Pubmed
Tsunoda,
H+ -pumping rhodopsin from the marine alga Acetabularia.
2006,
Pubmed
,
Xenbase
Váró,
Characterization of the photochemical reaction cycle of proteorhodopsin.
2003,
Pubmed
Váró,
Photoreactions of bacteriorhodopsin at acid pH.
1989,
Pubmed
Wang,
Spectroscopic and photochemical characterization of a deep ocean proteorhodopsin.
2003,
Pubmed
Wanko,
Effect of polarization on the opsin shift in rhodopsins. 1. A combined QM/QM/MM model for bacteriorhodopsin and pharaonis sensory rhodopsin II.
2008,
Pubmed
Waschuk,
Leptosphaeria rhodopsin: bacteriorhodopsin-like proton pump from a eukaryote.
2005,
Pubmed
