In this paper we report results on second-harmonic generation ~SHG! from aqueous suspensions of the purple membrane of Halobacterium halobium. A detailed theory describing this SHG signal is supported by results for the angular distribution of the harmonic emission and validated by experimental measurements with circularly polarized pump radiation—a condition that normally precludes SHG. Hence ...

as follows: 500 ml 230 medium 100 reciprocating movements per min for 5 days at Low purple membrane production is observed under conditions of sufficient aeration: cells were grown in Erlenmeyer flasks containing only 90 ml medium under otherwise in the presence of mM nicotine yielded cells with ml medium) or (90 ml of bacteria-opsin, respectively (‘nicotine [7 ] Basal salt solution contained l...

The vertical dimensions of the well-characterized test samples tobacco mosaic virus, T4 bacteriophage polyhead, purple membrane, and hexagonally packed intermediate (HPI) layer were investigated by tapping mode scanning force microscopy (SFM) in solution. Purple membrane and HPI layer were imaged in both contact mode and tapping mode SFM for direct comparison. All vertical dimensions match the ...

We located a heavy metal label, mercurilated phenylglyoxal, in both the primary sequence and in the tertiary structure of bacteriorhodopsin. This label modified arginines 225 and 227, which are on the COOH-terminal helix (G). In the projected electron potential difference map, the major site is close to the central inner helix. From this result we conclude that helix 1 could not be the COOH-ter...

1. Two dyes, bromocresol purple and ethyl red, were tested for their ability to register solution and membrane changes resulting from the illumination of suspensions of isolated chloroplasts. 2. Bromocresol purple can measure the external (suspension) pH both rapidly and accurately if the following precautions are observed: (a) since bromocresol purple stimulates electron flow to oxygen, either...

Tzvetana R. Lazarova and M aya Y. Velitchkova Central Laboratory of Biophysics, Bulgarian Academy of Sciences, Akad. G. Bonchev Str., bl. 21, Sofia 1113, Bulgaria Z. Naturforsch. 48c, 500-503 (1993); received July 3/September 16, 1992 Purple Membranes, Apomembranes, Retinal, Membrane Fluidity, Spin Label Three spin-labelled fatty acids were used to detect the dynamics of lipid bilayer of apomem...

Treatment of the purple membrane with carboxypeptidase A, Pronase, or papain, results in the cleavage of amino acids from the carboxyl terminus of bacteriorhodopsin, a maximum of about 17 amino acids being released with papain. Protease-treated bacteriorhodopsin, after denaturation, refolds to the native structure, binds retinal as tightly as the intact protein and, on reconstitution into vesic...

Spin-dependent photoelectron transmission and spin-dependent electrochemical studies were conducted on purple membrane containing bacteriorhodopsin (bR) deposited on gold, aluminum/aluminum-oxide, and nickel substrates. The result indicates spin selectivity in electron transmission through the membrane. Although the chiral bR occupies only about 10% of the volume of the membrane, the spin polar...

The dynamics of proton binding to the extracellular and the cytoplasmic surfaces of the purple membrane were measured by laser-induced proton pulses. Purple membranes, selectively labeled by fluorescein at Lys-129 of bacteriorhodopsin, were pulsed by protons released in the aqueous bulk from excited pyranine (8-hydroxy-1,3,6-pyrenetrisulfonate) and the reaction of protons with the indicators wa...