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While SNAP/CLIP-tag technologies are complementary to GFP, there are several applications for which SNAP- and CLIP-self-labeling technologies are advantageous.
| Application |
SNAP-tag/CLIP-tag |
GFP and other fluorescent proteins |
| Time-resolved fluorescence |
Fluorescence can be initiated upon addition of label |
Color is genetically encoded and always expressed. Also, photoactivatable fluorescent proteins require high intensity laser light, which may activate undesired cellular pathways (e.g., apoptosis) |
| Pulse-chase analysis |
Labeling of newly synthesized proteins can be turned off using available blocking reagents (e.g., SNAP-Cell® Block) |
Fluorescence of newly synthesized proteins cannot be quenched to investigate dynamic processes |
| Ability to change colors |
A single construct can be used with different dye substrates to label with multiple colors |
Requires separate cloning and expression for each color |
| Surface specific labeling |
Can specifically label subpopulation of target protein expressed on cell surface using non-cell permeable substrates |
Surface subpopulation cannot be specifically visualized |
| Visualizing fixed cells |
Resistant to fixation; strong labeling |
Labile to fixation; weak labeling |
| Pull-down studies |
"Bait" proteins can be covalently captured on BG beads |
Requires anti-GFP antibody to non-covalently capture “bait" protein, complicating downstream analysis |
| Live animal imaging |
Near-IR dyes are available, permitting deep tissue visualization |
Limited to visible wavelengths |
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