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Fluorescent Protein Guide: Empty Backbones


Background

Fluorescent proteins are genetically encoded tools that are used extensively by life scientists. The original green fluorescent protein (GFP) was cloned in 1992 (Prasher et al., Gene, 1992), and since then scientists have engineered numerous GFP-variants and non-GFP proteins that result in a diverse set of colors.

Addgene has assembled a collection of empty plasmid backbones with different fluorescent tags for you to create fusion proteins with your gene of interest. These are organized By Color of the fluorescent protein and By Expression Species .

The content for this page was generated with the help of Erik Snapp .

Empty Backbones for Fluorescent Protein Fusions (Organized by Color)

For each table:

  • Excitation and Emission maximum are listed in nm.
  • Brightness is the product of exctinction coefficient and quantum yield divided by 1000.
  • pKa is the pH at which fluorescence intensity is 50% of its maximum value.
  • Maturation is the time for fluorescence to obtain half-maximal value.
  • Structure describes the monomeric or oligomeric state of the protein. Many FPs are monomers at low concentration but are prone to dimerization at high concentration, so this is noted here. Proteins that are derived from GFP and contain the A206K mutation are monomeric at all concentrations, so this is mutation is noted when present.
  • For more information on the properties of many of these proteins, see:
    • Cranfill et al., Nature Methods 2016 Jul;13(7):557-62.
    • FPbase: A database for users of fluorescent proteins created by Talley Lambert at Harvard Medical School
    • More References below

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Blue/UV

Protein Excitation (nm) Emission (nm) Brightness pKa Maturation Structure Plasmids
Sirius 355 424 4 3.0 Prone to dimerization
SBFP2 380 446 13 Monomer (A206K)
Azurite 383 450 14 5 Prone to dimerization
mAzurite 383 450 14 5 Monomer (A206K)
EBFP2 383 448 17 4.5 Prone to dimerization
moxBFP 385 448 17 Monomer (A206K)
  • moxBFP - Mammalian Expression
mKalama1 385 456 16 5.5 Monomer (A206K)
mTagBFP2 399 456 32 2.7 12 min Prone to dimerization
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Cyan

Protein Excitation (nm) Emission (nm) Brightness pKa Maturation Structure Plasmids
Aquamarine 420 474 23 3.3 Prone to dimerization
ECFP 433 475 13 4.7 Prone to dimerization
Cerulean 433 475 27 4.7 Monomer (A206K)
mCerulean3 433 475 32 3.2 Monomer (A206K)
moxCerulean3 434 474 36 3.2 Monomer (A206K)
SCFP3A 433 474 17 4.5 Monomer (A206K)
mTurquoise2 434 474 28 3.1 Monomer (A206K)
CyPet 435 477 18 5 Monomer
AmCyan1 453 486 11 Tetramer
MiCy (Midoriishi-Cyan) 472 495 25 6.6 Dimer
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Green

Protein Excitation (nm) Emission (nm) Brightness pKa Maturation Structure Plasmids
iLOV 447 497 Monomer
AcGFP1 475 505 28 Prone to dimerization
sfGFP 485 507 54 Prone to dimerization
moxGFP 486 510 50 Monomer (A206K)
  • moxGFP - Mammalian Expression
mEmerald 487 509 39 6 Monomer (A206K)
EGFP 488 507 34 6 Prone to dimerization
mEGFP 488 507 34 6 Monomer (A206K)
mAzamiGreen 492 505 41 5.8 Monomer
cfSGFP2 493 517 34 5.4 Monomer (A206K)
  • cfSGFP2-N - Mammalian Expression (cysteine-free SGFP2)
ZsGreen 493 505 39 Tetramer
  • pHIV-Zsgreen - Mammalian Expression (this is a bicistronic vector rather than a fusion protein vector)
  • ZsGreen1-N1 - Mammalian Expression
SGFP2 495 512 30 Monomer (A206K)
Clover 505 515 84 6.1 30 min Prone to dimerization
dClover2 505 515 Dimer (A206K)
mClover3 506 518 85 6.5 Monomer (A206K)
mNeonGreen 506 517 93 5.7 10 min Monomer
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Yellow

Protein Excitation (nm) Emission (nm) Brightness pKa Maturation Structure Plasmids
EYFP 513 527 51 6.9 Prone to dimerization
Topaz 514 527 57 Prone to dimerization
mTopaz 514 527 Monomer (A206K)
mVenus 515 528 53 6 Monomer (A206K)
moxVenus 514 526 44 Monomer (A206K)
SYFP2 515 527 69 6 Monomer (A206K)
mGold 515 530 68 5.9 Monomer
mCitrine 516 529 59 5.7 Monomer (A206K)
YPet 517 530 80 5.6 Prone to dimerization
ZsYellow1 529 539 8 Tetramer
mPapaya1 530 541 36 6.8 Monomer
mCyRFP1 528 594 18 5.6 Monomer
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Orange

Protein Excitation (nm) Emission (nm) Brightness pKa Maturation Structure Plasmids
mKusabira-Orange (mKO) 548 559 31 5 4.5 hr Monomer
mOrange 548 562 49 6.5 2.5 hr Monomer
mOrange2 549 565 35 6.5 4.5 hr Monomer
mKO2 551 565 40 5.5 Monomer
TurboRFP 553 574 62 4.4 Dimer
tdTomato 554 581 95 4.7 1 hr Tandem-dimer
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Red

Protein Excitation (nm) Emission (nm) Brightness pKa Maturation Structure Plasmids
mScarlet-H 551 592 15 4.8 4.4 hr Monomer
mNectarine 558 578 26 6.9 30 min Monomer
mRuby2 559 600 43 5.3 150 min Prone to dimerization
eqFP611 559 611 35 Tetramer
DsRed2 563 582 24 Tetramer
mApple 568 592 37 6.5 30 min Monomer
mScarlet-I3 568 592 68 4.2 2 min Monomer
mScarlet3 569 592 78 4.5 37 min Monomer
mScarlet 569 594 71 5.3 2.9 hr Monomer
mScarlet-I 569 593 57 5.4 36 min Monomer
mStrawberry 574 596 26 4.5 50 min Monomer
FusionRed 580 608 18 Monomer
mRFP1 584 607 13 4.5 1 hr Monomer
mCherry 587 610 16 4.5 15 min Monomer
mCherry2 587 610 Monomer
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Far-Red

Protein Excitation (nm) Emission (nm) Brightness pKa Maturation Structure Plasmids
mCrimson3 588 615 - Monomer
HcRed1 588 618 0.3 Dimer
dKatushka 588 635 22 5.5 Dimer
mKate1.3 588 635 25 Monomer
mPlum 590 649 4 4.5 100 min Monomer
mRaspberry 598 625 13 55 min Monomer
TagRFP675 598 675 4 5 Prone to dimerization
mNeptune 600 650 13 5.4 35 min Prone to dimerization
mNeptune2 600 650 21 Prone to dimerization
mCarmine 603 675 5.81 5.58 Monomer
mCardinal 604 659 17 5.3 27 min Prone to dimerization
mMaroon 610 652 - Monomer
TagRFP657 611 657 0.34 5.3 27 min Prone to dimerization
smURFP + BV 642 670 32 39 min Prone to dimerization
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Near-Infrared

Protein Excitation (nm) Emission (nm) Brightness pKa Maturation Structure Plasmids
miRFP670 642 670 12 4.5 Monomer
iRFP670 643 670 13 4 ~5 hr Dimer
iRFP682 663 682 10 4.5 ~5hr Dimer
miRFP703 673 703 8 4.5 Monomer
iRFP702 673 702 8 4.5 ~5hr Dimer
miRFP709 683 709 4 4.5 Monomer
mIFP 683 704 7 3.5 Monomer
IFP2.0 684 708 7 Prone to dimerization
iRFP (aka iRFP713) 690 713 6 4.5 2.8 hr Dimer
iSplit 690 713 5 Dimer
iRFP720 702 720 6 4.5 ~5hr Dimer
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Long Stokes Shift

Protein Excitation (nm) Emission (nm) Brightness pKa Maturation Structure Plasmids
T-sapphire 399 511 26 4.9 1.3 hr Prone to dimerization
mT-sapphire 399 511 Monomer (A206K)
mAmetrine 406 526 26 6 0.8 hr Monomer (A206K)
LSSmOrange 437 572 23 5.7 2.3 hr Monomer
mKeima Red 440 620 3 6.5 4.4 hr Monomer
dKeima Red 440 616 22 6.5 Dimer
LSSmKate1 463 624 3 3.2 1.7 hr Monomer
LSSmKate2 460 605 4 2.7 2.5 hr Monomer
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Photoactivatable (e.g. off to on)

Excitation and Emission wavelengths after activation.

Protein Excitation (nm) Emission (nm) Brightness pKa Maturation Structure Plasmids
Phamret 458 517 14 Monomer
PA-sfGFP 485 511 Prone to dimerization
mPA-Emerald 487 509 - Monomer (A206K)
PA-GFP 504 517 14 Monomer (A206K)
PATagRFP 562 595 25 5.3 75 min Prone to dimerization
PAmCherry1 564 595 8 6.3 23 min Monomer
PAmCherry2 570 596 13 6.2 18 min Monomer
PAmCherry3 570 596 5 6.2 25 min Monomer
PAmKate 568 628 5 5.6 19 min Monomer
PAiRFP1 690 717 3 Dimer
PAiRFP2 692 719 3 Dimer
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Photoconvertible (e.g. green to red)

Protein Excitation (nm) Emission (nm) Brightness pKa Maturation Structure Plasmids
Dendra2 490 / 553 507 / 573 23/19 6.6/6.9 Monomer
mEos2 506 / 571 516 / 581 47 / 30 5.6/6.4 Prone to oligomerization
mEos3.2 507 / 572 516 / 580 53 / 18 5.4/5.8 20 min Monomer
mEos4a 505 / 569 516 / 581 Prone to oligomerization
mEos4b 505 / 569 516 / 581 Monomer
dEos 505 / 569 516 / 581 55 / 20 Dimer
tdEos 505 / 569 516 / 581 55 / 20 Tandem dimer
mKikGR 507 / 583 517 / 593 34 / 18 6.6/5.2 Monomer
Kaede 508 / 572 518 / 580 87 / 20 5.6/5.6 Tetramer
PSmOrange 548 / 634 565 / 662 58 / 9 6.2/5.6 1.6 hr Monomer
PSmOrange2 546 / 619 561 / 651 31 / 7 6.6/5.4 3.5 hr Monomer
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Photoswitchable (e.g. off to on to off)

Protein Excitation (nm) Emission (nm) Brightness pKa Maturation Structure Plasmids
rsTagRFP 440 / 567 585 / 585 0.02 / 4.0 6.6 43 min Prone to dimerization
rsEmerald 491 508
rsGFP1 493 510
Dronpa3 503 518 19 Monomer
mGeos-M 503 / 569 514 / 581 44 4.7 Prone to dimerization
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Fluorescent Timers

Protein Excitation (nm) Emission (nm) Brightness pKa Maturation Structure Plasmids
Fast-FT 403(blue), 583(red) 466(blue), 606(red) 14.9(blue), 6.8(red) 2.8/4.1 7.1 hr (red) Monomer
Medium-FT 401(blue), 579(red) 464(blue), 600(red) 18.4(blue), 5.8(red) 2.7/4.7 3.9 hr (red) Monomer
Slow-FT 402(blue), 583(red) 465(blue), 604(red) 11.7(blue), 4.2(red) 2.6/4.6 28 hr (red) Monomer
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Empty Backbones for Fluorescent Protein Fusions (Organized by Expression Species)

Organism/Expression System Plasmids
Mammalian
Insect
Zebrafish, Sea urchin, Xenopus, and C. elegans
Yeast
  • Thorn Lab Vectors - Includes tagging with a wide variety of colors, some specifically optimized for yeast
  • Lindquist Lab Vectors - Gateway cloning; includes tagging with ECFP, EYFP, DsRed, Cerulean
Bacteria
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References:

  • Cranfill et al.: Nature Methods July 2016, Vol. 13(7):557-62
  • Olympus Confocal: The Fluorescent Protein Color Palette
  • NIC Wiki: Nikon Imaging Center at UCSF / QB3 Wiki
  • FPbase: A database created by Talley Lambert at Harvard Medical School
  • Zeiss Microscopy: Optical Highlighters
  • NIC Wiki PSFP: Nikon Imaging Center at UCSF / QB3 Wiki
  • Stepanenko et al.: BioTechniques, Vol. 51, No. 5, November 2011, pp. 313–327
  • Scholarpedia: Entry by Robert Campbell
  • Spectra Database: Graphing site hosted at the University of Arizona
  • Shaner et al.: Journal of Cell Science, Vol. 120, December 2007, pp. 4247-4260
  • Shaner et al.: Nature Methods, Vol.5 No. 6, June 2008, pp. 545-51
  • Shcherbakova et al.: Journal of the American Chemical Society, May 2012, Vol. 134 No.18, pp. 7913–7923
  • Hoi et al.: Chemistry & Biology, October 2013, Vol. 20 No. 10, pp.1296-304
  • Kogure et al.: Nature Biotechnology, May 2006, Vol. 24 No. 5, pp.577-81
  • Shcherbo et al.: Nature Methods, September 2007, Vol. 4 No. 9, pp. 741-6
  • Shemiakina et al.: Nature Communications, November 2012, Vol. 3 No. 1204
  • Wiedenmann et al.: Journal of Biomedical Optics, Feburary 2005, Vol. 10 No. 1, p. 14003
  • Chu et al.: Nature Methods, May 2014 Vol. 11 No. 5, pp.572-8
  • Yu et al.: Nature Communications, May 2014 Vol. 15 No. 5, p. 3626

Do you have suggestions for other plasmids that should be added to this list?

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