Gunner, "Calculation of proton transfers in bacteriorhodopsin bR and M intermediates," Biochemistry, vol.
Royant et al., "Protein, lipid and water organization in bacteriorhodopsin crystals: a molecular view of the purple membrane at 1.9 A resolution," Structure, vol.
PDB number Protein name 1U19 Rhodopsin 2Z73 Rhodopsin 1GU8 Sensory rhodopsin II 1JV6 Bacteriorhodopsin
1XIO Anabaena sensory rhodopsin 3A7K Halorhodopsin 3DDL Xanthorhodopsin PDB number Species 1U19 Bos taurus (bovine) 2Z73 Todarodes pacificus (Japanese flying squid) 1GU8 Natronobacterium pharaonis 1JV6 Halobacterium salinarum 1XIO Nostoc sp.
The membrane's purple color comes from a bacteriorhodopsin component called retinal, which is strongly bound to an amino acid inside the membrane channel.
That behavior has prompted research on the use of bacteriorhodopsin as the light-sensitive element in artificial retinas and as memory or processing units in protein-based or optical computers (SN: 3/8/97, p.
A thin film of bacteriorhodopsin can also change its color in response to an external electric field.
Like ink on paper, images on a bacteriorhodopsin display are visible in ambient light.
Included in this group might be storage in protein bacteriorhodopsin
, the living scum (Halobacterium halobium) found off San Francisco Bay, and multiwavelength storage using strands of human DNA molecules.
The protein, called bacteriorhodopsin, converts light energy into electric energy quickly and efficiently.
Bacteriorhodopsin is an attractive material for optical computers because it exists in two stable forms, one purple and one yellow.
Aaron Lewis and his colleagues at the Hebrew University of Jerusalem impregnated a plastic film with equal concentrations of the purple and yellow forms of bacteriorhodopsin. As they report in the March 7 Science, they then illuminated the film with two lasers, modifying the light using an array of lenses with focal properties that differ slightly for the two wavelengths.
That varying intensity altered the relative concentrations of the purple and yellow forms of bacteriorhodopsin.