Zsolt Dancsházy

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A new two step photobleaching process is observed under continuous illumination of bacteriorhodopsin. This photobleaching is considerable even at physiological temperatures and becomes large at 50-60 degrees C. The photobleaching also increases with increasing pH from 7 to 10. We suggest that the bleaching at its final stage could be due to the dissociation(More)
Photobleaching of bacteriorhodopsin (BR) by continuous light has recently been demonstrated. This bleaching consists of at least two subsequent product states. One of them is absorbing maximally in the blue spectral region. Our present study shows that upon illumination of the bleached sample with blue light a back photoprocess appears, resulting in(More)
The electric response of a back photoreaction in the bacteriorhodopsin photocycle was investigated. The proton pumping activity of green flash excited bacteriorhodopsin stops if the M412 form is illuminated by blue light (Karvaly and Dancsházy, 1977). In the present work a fast negative displacement current signal was measured in an oriented membrane(More)
Photoelectric properties of bacteriorhodopsin incorporated into a bimolecular lipid membrane were investigated with special regard to the mechanism of photoelectric field generation. It was shown that besides its proton pump and electric generator functions bacteriorhodopsin works as a possible molecular regulator of the light-induced membrane potential.(More)
Methylation of the nonactive site lysines of bacteriorhodopsin to form permethylated bacteriorhodopsin does not interfere with the formation of the short wavelength intermediate M412 or light-induced proton release/uptake. The absorption spectrum is similar to that of the native bacteriorhodopsin. However, additional monomethylation of the active site(More)
Time-resolved, flash-induced difference absorbance spectra (300-700 nm) at pH 10.5 and 5 degrees C for the bacteriorhodopsin photocycle fast and slow decaying forms of the M intermediate (M(f) and M(s), respectively) and R intermediate are reported. The main distinguishing features are as follows: For M(f), DeltaA(max) = 412 nm, a shoulder at 436 nm, no(More)
The permanent dipole moment, polarizability, and the retinal angle of Halobacterium halobium purple membranes were determined at different pH values. All of the parameters have a maximum between pH 5 and 6. There is a reversal in the direction of the permanent dipole moment near pH 5. The value of permanent dipole moment was determined to be 60 D/protein at(More)