OPTICAL AND ELECTRICAL-PROPERTIES OF ORIE NTED PURPLE MEMBRANE FILMS CONTAINING D96N BACTERIORHODOPSIN AT DIFFERENT HUMIDITIES

Highly oriented purple membrane films containing bacteriorhodopsin (BR ) from Halobacterium salinarium D96N mutant were electrophoreticaly de posed onto the transparent indium-tin-oxide glass electrode surface. T o decrease a decay in the dark of the BR photocycle, product M(412) th e sample was incubated in 20 mM berate buffer, pH 10,0. Contrary to th e wild type (WT) BR, the decay of the mutant product did not depend on humidity. The yellow light-induced potential in this sample recovered with the decay time constant of 15-25 min at room temperature and hum idity below 30%. This slow relaxation was; markedly accelerated by add itional blue-light illumination. Such properties of photovoltage in th e D96N mutant films treated with berate buffer at alkaline pH are comp arable to those of WT BR at temperatures about 0 degrees C. This mutan t may be used for developing systems for storage of optical informatio n which can be read out in the electric mode.