Matt:LabNotes/2015-7-16

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Dye-Coupling with Alexa 488 and Alexa 647[edit]

Dan's best practice dye coupling protocol
Generic dye coupling protocol

SNAP25-488 CUX2-647

  1. Warm DMSO and bicarbonate labeling buffer and nuclease free H2O to room temperature
  2. Add 5 uL DNA (~1ug/ul) and 3 uL of sodium bicarbonate buffer
  3. Make 2 25ul aliquots of SNAP25 48probe to prevent so many freeze-thaws in the future
  4. Denature samples for 5 minutes at 95C, then snap cool using ice box
  5. Dissolve 1 vial of reactive dye in 2 uL DMSO; do multiple cycles of vortex and spin down during 5 minutes of denaturing
    • Dye cannot be saved for later use. Use immediately!
  6. Add 8 uL sample to dye tube
  7. Incubate in the dark for 1 hour
  8. Add 10 uL 3M NaOAc and 80 uL 1xTE to sample
  9. Centri-Sep column purification after incubation
    • Use 1X TE Buffer
    • No vacufuge
  10. Ethanol Precipitation; add 250 uL 100% EtOH, 10 uL NaOAc and 0.5 uL glycoblue; incubate overnight
  11. Centrifuge at 4 C for 30 minutes (14,000 rpm)
  12. Remove supernatant and add 750 uL chilled 80% EtOH
  13. Centrifuge 5 minutes at 4 C
  14. Dry the pellet in the hood
  15. Resuspend pellet in 12 uL TE
  16. Check dye:probe ratio with Nanodrop
    • Use 324.5 g/mol/bp as molar mass of ssDNA (6490 g/mol of 20-mer)
    • Starting DNA mass = 5ul * 1ug/ul
Probe ssDNA (ng/ul) 488 dye (pmol/ul) 647 dye (pmol/ul) dye:probe ratio ssDNA mass (ug) ssDNA start mass (ug) ssDNA Yield (%)
SNAP25-488 220.1 37.4 0 1.10 2.64 5 52.8
CUX2-647 237.6 0.6 43.9 1.20 2.85 5 57.0