This document presents information on protein memory. It discusses the history of protein memory discovery and the current status of research. The document describes how protein memory works using the bacteriorhodopsin protein, which can be switched between different states using different wavelengths of light to store data. Methods for writing, reading, and erasing data using the photo cycle properties of bacteriorhodopsin are explained. Potential applications of protein memory and its advantages over conventional electronic RAM are also summarized.

1. A Presentation By: ……….
Ajay Singh
Electronics and Communication
Student of
Engineering
B. Tech.

2. Contents
Overview
History
Present Status of Protein Memory
RAM Types
Protein Memory
Data Write, Read & Erase Techniques
Practical Memory Cell
Applications
Conclusion
References

3. Overview
•Protein memory is an experimental means of storing
data.
•Using proteins, that respond to light from bacteria found
in salt water, a small cube can store large amounts of
data.
•By using lasers, the protein can be changed depending
on various wave lengths, allowing them to store and
recall data. As a result protein can be used to store
enormous amounts of data using lasers to read and write
binary code.

4. History of Protein Memory
Protein memory was discovered by Walther Stoeckenius and
Dieter Oesterhelt at Rockefeller University in New York.
They discovered that a protein isolated from a salt marsh
bacterium exhibited photosensitive properties. They called this
protein bacteriorhodopsin, because it was very similar to the
protein, rhodopsin that founds in the eyes of humans and
animals.

5. Present Status
Not used for commercial applications.
Used for military and scientific applications..
Researches are going on for….
 High speed high capacity memory for commercial applications
 Ultimate machine intelligence with the aid of genetic engineering
(A memory that mimics human brain).
 Carry a small encyclopedic cube containing all the information we
need !!.

6. RAM Types
DRAM (Dynamic RAM)
 SRAM (Static RAM)

7. DRAM (Dynamic RAM)
 Must be refreshed every few millisecond
 Cheaper and widely used
 Low power consumption
SRAM (Static RAM)
 Faster than DRAM
 Costly

8. Protein Memory
How Protein Memory compete with electronic memory?
 Speed
 Reliability
 Capability
 Cost
Basic unit of Protein Memory
Bacterial protein molecule - Bacteriorhodopsin (bR)

9. Protein Memory (Cont.)
Bacteriorhodopsin ( bR )
Purple membranes of Halo bacterium halobium.
Changes mode of operation upon light incident.
Light energy to chemical energy conversion.

10. Protein Memory (Cont.)
Why bR?
 bR grows in salt marshals
 Where temp can exceed 150 degree Farad for extended
time period
 Salt concentration in approx 6 times that of sea water
 Survival indicates its resistance to thermal and
photochemical damages
 Excellent optical characteristics & Long term stability

11. Protein Memory (Cont.)
Photo Cycle of Bacteriorhodopsin
Chromophore – Light absorbing component
Light energy triggers a series of complex internal
structural changes - Photocycle

12. Protein Memory (Cont.)
Photo cycle of Bacteriorhodopsin

13. Protein Memory (Cont.)
Molecular Structure
Quite similar to ‘Rhodopsin’, the light detecting
pigment in retinas of human eye

14. Data Writing Technique Photo cycle

15. Data Reading Technique Photo Cycle

16. Data Erasing Technique
 Blue laser erases encoded data
 Q state absorb blue light and return to original bR state
 Individual data can be erased using blue laser

17. Birge’s Memory Cell
 Stores data with 10,000 molecules per bit
 Molecule switches in 500 femtoseconds
 Speed only limited by laser steering speed
 Estimated that Data stored live around 5 years without any
refreshment

18. Applications of bR
Ultra fast RAM
Finger print processing
Optical switches
Neural Logic gates (genetic engineering)

19. Conclusion
 During the past decade, the speed of computer processors
increased almost 1,000 times, where as data storage
capacities increased only by a factor of 50. Also, the transfer
of data within the computer remains the principal bottleneck
that limits performance.
 Protein memories use laser beam, which improve their life
with reduction in wear and tear.

20. References
 Protein Based Computers Birge, Robert R., Scientific American
March 1995
 Molecular and Biomolecular Electronics, Birge, Robert R. Ed.,
American Chemical Society
 Organic Chemistry Baker, A. David, Robert Engel.
 www.quantum.com
 www.che.syr.edu (Department of Chemistry, Syracuse
University)

21. Q&A

22. THANK YOU

23. Backup Slides

24. Birge’s Memory Cell Vs.
Conventional Electronic RAM
Data access

300 times faster than conventional RAM
Storage Capacity
 4096 x 4096 bits page
 16 Mb per page
 1000 such pages
 16 Gb total capacity

25. Birge’s Memory Cell Vs.
Conventional Electronic RAM (Cont.)
`
Cost
 bR protein can be produced in large volumes at low
price
 Birge’s memory cell costs 2 US $ and can store 7 Gb.

26. Birge’s Memory Cell Vs.
Conventional Electronic RAM (Cont.)
`
Transportation
 Can remove small data cubes and ship gigabytes of data
 No moving parts – safer than small hard drives
 Can operate in wider range of temperatures