Protein-coated disc From Wikipedia, the free encyclopedia
Jump to: navigation, search This article contains information about a scheduled or expected future product. It may contain preliminary or speculative information, and may not reflect the final version of the product. Protein-Coated Disc (PCD) is a theoretical optical disc technology currently being developed by Professor V Renugopalakrishnan of Harvard Medical School. PCD would greatly increase storage over Holographic Versatile Disc optical disc systems. It involves coating a normal DVD with a special light-sensitive protein made from a genetically altered microbe, which would in principle allow storage of up to 50 Terabytes on one disc. It is currently unknown when or even if this medium will become commercially available.
[edit] Technology The light-activated protein is found in the membrane of a salt marsh microbe Halobacterium salinarum and is also known as bacteriorhodopsin (bR). It captures and stores sunlight to convert it to chemical energy. When light shines on bR, it is converted to a series of intermediate molecules each with a unique shape and colour before returning to its "ground state". Since the intermediates generally only last for hours or days, Prof Renugopalakrishnan and his colleagues modified the DNA that produces bR protein to produce an intermediate that lasts for more than several years. They also engineered the bR protein to make its intermediates more stable at the high temperatures generated by storing terabytes of data. The information in such discs would be highly dense, due to being stored in proteins that are only a few nanometres across.