Photochromic fluorescent proteins and optical memory storage devices based on fluorescent proteins
AssigneeThe Regents of the University of California
InventorsRoger Y. Tsien, Roger Heim, Andrew B. Cubitt, Robert M. Dickson, William E. Moerner
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Abstract
Photochromic fluorescent protein moiety having two or more stable states having excitation or emission spectra that are shifted from one wavelength region to another wavelength region in the two states are described. The photochromic material switches between states by irradiation with light of appropriate wavelengths. The two states are preferably stable at room temperature and in the dark. The switching between states can be reversible.
Claims87
An optical memory device, comprising:
- a photochromic fluorescent protein moiety that is capable of being converted from a first fluorescent state to a second fluorescent state by irradiation with a writing wavelength in an optical memory device,
- wherein said first fluorescent state has a first excitation wavelength maximum, and
- wherein said photochromic fluorescent protein moiety is capable of being converted from said second fluorescent state to said first fluorescent state by irradiation with an erasing wavelength in an optical memory device.
An optical memory device comprising:
- an Aequorea-related photochromic fluorescent protein moiety which is capable of being converted from a first fluorescent state to a second fluorescent state by irradiation with a writing wavelength in an optical memory device,
- wherein said photochromic fluorescent protein moiety is capable of being converted from said second fluorescent state to said first fluorescent state by irradiation with an erasing wavelength in an optical memory device, and
- wherein a medium including a plurality of said photochromic fluorescent protein moieties distributed throughout said medium, said medium being configured as a planar surface or a volume,
- further wherein said first fluorescent state has a first emission wavelength maximum, said first fluorescent state is capable of being excited by a reading wavelength in an optical memory device.
A composition of matter, comprising:
- a photochromic fluorescent protein moiety capable of being converted from a first fluorescent state to a second fluorescent state by irradiation with a writing wavelength in an optical memory device,
- wherein said first fluorescent state has a first excitation wavelength maximum, said second fluorescent state has a second excitation wavelength maximum, excitation of said second fluorescent state at said second wavelength excitation maximum produces an intensity that is at least four times greater than said intensity of said first fluorescent state at said second excitation wavelength maximum.
A method for storing and recovering information comprising:
- addressing a photochromic fluorescent protein moiety which is capable of being converted from a first fluorescent state to a second fluorescent state by irradiation with a writing wavelength in an optical memory device,
- wherein said first fluorescent state has a first excitation wavelength maximum, and
- wherein said photochromic fluorescent protein moiety is capable of being converted from said second fluorescent state to said first fluorescent state by irradiation with an erasing wavelength in an optical memory device, in a medium including a plurality of said photochromic fluorescent protein moieties;
- exposing said photochromic fluorescent protein moiety to said writing wavelength;
- irradiating said photochromic fluorescent protein moiety with a reading wavelength in an optical memory device;
- and detecting an output to determine whether said photochromic fluorescent protein moiety is in said first fluorescent state or second fluorescent state.
A method of improving a photochromic response of a photochromic fluorescent protein moiety, comprising:
- growing a plate of bacteria containing a large number of mutations that express a photochromic fluorescent protein moiety to provide a plurality of colonies;
- exposing said plurality of colonies to a first excitation wavelength and measuring an intensity of a resulting first emission I(A1) from said exposure to said first excitation wavelength of a colony;
- exposing said plurality of colonies to a second excitation wavelength and measuring an intensity of a resulting second emission I(B1) from said exposure to said second excitation wavelength of a colony;
- exposing said plurality of colonies to an isomerization wavelength;
- exposing said plurality of colonies to said first excitation wavelength and measuring an intensity of a first emission I(A2) from said exposure to said first excitation wavelength for a colony;
- exposing said plurality of colonies to said second excitation wavelength and measuring an intensity of a second emission I(B2) from said exposure to said second excitation wavelength for a colony;
- determining said ratio of emission intensities from said colony before and after exposure to said isomerization wavelength;
- and
- selecting said colony having improved photochromic response of said photochromic fluorescent protein moiety if said ratio of emission intensities is substantially different from an average ratio of emission intensities for said plurality of colonies.
An isolated nucleic acid sequence which encodes a photochromic fluorescent protein moiety capable of being converted from a first fluorescent state to a second fluorescent state by irradiation with a writing wavelength in an optical memory device,
- wherein said first fluorescent state has a first excitation wavelength maximum, said second fluorescent state has a second excitation wavelength maximum, excitation of said second fluorescent state at said second excitation wavelength maximum produces an intensity that is at least four times greater than said intensity of said first fluorescent state at said second excitation wavelength maximum.
An expression vector comprising expression control sequences operatively linked to a nucleic acid sequence coding for said expression of a photochromic fluorescent protein moiety capable of being converted from a first fluorescent state to a second fluorescent state by irradiation with a writing wavelength in an optical memory device,
- wherein said first fluorescent state has a first excitation wavelength maximum, said second fluorescent state has a second excitation wavelength maximum, excitation of said second fluorescent state at said second excitation wavelength maximum produces an intensity that is at least 4 times greater than said intensity of said first fluorescent state at said second excitation wavelength maximum.
A host cell transfected with an expression vector, comprising:
- an expression control sequence operatively linked to a sequence coding for said expression of a photochromic fluorescent protein moiety capable of being converted from a first fluorescent state to a second fluorescent state by irradiation with a writing wavelength in an optical memory device,
- wherein said first fluorescent state has a first excitation wavelength maximum, said second fluorescent state has a second excitation wavelength maximum, excitation of said second fluorescent state at said second excitation wavelength maximum produces an intensity that is at least four times greater than said intensity of said first fluorescent state at said second excitation wavelength maximum.
Dependencies are inferred from the claim text.