Bacteriorhodopsin variants as versatile media in optical processing.

The photochromic properties of bacteriorhodopsin (BR), in addition to its longevity and excellent reversibility, are attractive features for the construction of light-sensitive media for optical information processing. However, the various optical techniques require media with specifically adapted and widely differing properties. Genetic engineering of BR and biotechnological production of mutated BRs is the key for the utilization of this photochromic compound in optical applications. Mutated BRs, generated by single and double amino acid exchanges, have been used as recording media for optical applications such as phase conjugation or long-term data storage at room temperature.