Not all diazirine proteomics tags photoactivate alike
Comparing fully functionalized diazirine tags shows dialkyl tags LD/BD photolyze at 365 nm in minutes, while a new tiny terminal tag needs 302 nm light and labels fewer peptides.
Source
Evaluation of fully-functionalized diazirine tags for chemical proteomic applications
What they did
Authors synthesised a 109 Da terminal diazirine, measured 365 vs 302 nm photolysis by LC-MS, then profiled tag-only, fragment, staurosporine and JQ1 probes in HEK293T/K562 proteomes including TMT and crosslink-site mapping.
What they found
LD–F and BD–F t½ = 5.4 and 2.6 min at 365 nm; aryl Ar–F has a 29 min slow phase; DF/Tm barely activate at 365 nm (λmax 300–310 nm) but photolyze at 302 nm (t½ 10 and 5.8 min). LD/BD mapped 11.6/11.3% of enriched proteins to modified peptides versus fewer for Tm.
The limits
What it doesn't show
The ‘best’ tag still depends on the recognition ligand; St-series probes were not cell-permeable, so live-cell ranking is incomplete.
Key terms
- Fully functionalized (FF) tag
- A compact photoreactive plus reporter (alkyne) cassette appended to a ligand.
- Diazirine
- Three-membered CN2 ring that yields a carbene (or diazo) upon UV.
- LD / BD / Tm / Ar / DF
- Linear dialkyl, branched dialkyl, terminal, aryl, and difluoromethylalkynyl tag chemotypes.
- CuAAC reporter
- Alkyne handle used to attach biotin/fluorophore after photocapture.
- Minimalist tag
- The 109 Da terminal diazirine built to shrink background interactions.
Flashcards
Research intelligence for this paper
See its role on concept claims, tensions it is part of, placement history, and related discoveries.
Quiz yourself
At 365 nm, the fastest dialkyl tag half-life is about:
Common questions
Which tags photolyze well at 365 nm?
Dialkyl LD–F and BD–F (t½ 5.4 and 2.6 min).
What is the new tag’s mass and yield?
109 Da, 35% over three steps.
Do DF and Tm work at 365 nm?
Little photoactivation; they absorb near 300–310 nm.
Staurosporine probes live-cell permeable?
No—used in lysates.
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