Photo-reactive crosslinkers are widely used for nonspecific bioconjugation. While numerous options exist, the two most common photo-reactive chemical groups are diazirines and aryl-azides.
Photoreactive reagents like aryl azides and diazirines are most often used as heterobifunctional crosslinkers to capture binding partner interactions. They are typically used in the following manner:
- A purified bait protein is labeled with the crosslinker using the amine- or sulfhydryl-reactive end
- The labeled protein is then added to a lysate sample and allowed to bind its interactor
- Finally, photo-activation with UV light initiates conjugation via the phenyl azide group
Aryl azides have been the most popular photoreactive chemical group used in crosslinking and labeling reactions. When exposed to UV light (250-350nm), aryl azide forms a nitrene group that can do any of the following (1) initiate an addition reaction with the double bonds, (2) insertion into a C–H or N–H sites, (3) undergo a ring expansion to react with a nucleophile (e.g., primary amines).
Diazirines are a newer class of photoactive chemical group suitable for crosslinking and labeling reagents. The diazirine (azipentanoate) group has better photostability than phenyl azide groups, and is easily and efficiently activated with long-wave UV light (330-370nm).
Choose the right photoreactive crosslinker for your experiment
|Reactive Groups||Products||Spacer Arm (Å)||Cleavable by?||Water-soluble ?||Membrane permeable?|
|NHS ester/ aryl azide||ANB-NOS||7.7 Short||No||No||No|
|NHS ester/ diazirine||SDA||3.9 Short||No||No||Yes|
Featured photoreactive crosslinkers and accessories
Compact, UV-lamps with 252 nm, 302 nm and 365 nm short to long wavelength bulbs for use with photoactive crosslinkers and UV-crosslinking methods.
An amine-to-DNA crosslinker, composed of NHS-ester and psoralen reactive groups, which conjugates to DNA via light-activated intercalation next to pyrimidine bases.
Diazirine analogs of leucine and methionine for the expression of proteins in cell culture that will crosslink their protein interactors upon UV-light activation in vivo.
Chemical-tag purified proteins at primary amines that covalently crosslink and transfer biotinylation to protein interaction binding partners.
For Research Use Only. Not for use in diagnostic procedures.