Thermo Scientific Pierce SDAD (NHS-SS-Diaziridine) activates proven NHS-based The photochemical components of esters and bisaziridines are combined with conjugates containing amine molecules and virtually any other functional group. A 13.5Å spacer arm containing a cleavable disulfide bond separates the two photoreactive groups.

Features of SDAD (NHS-SS-Diaziridine):

•Membrane permeability— Suitable for in vivo Intracellular protein cross-linking
•Heterobifunctional—NHS ester group reacts with primary amines at pH 7 to 9 The reaction forms a covalent amide bond; when activated with long-wave UV light (330-370 nm), Diaziridine (azidopentanoic acid) group can be combined with any amino acid Efficient reaction of side chains or peptide backbone
•Controllable—Two-step chemical cross-linking activated using common laboratory UV lamps
•Easy to use—these Cross-linkers are photostable under typical laboratory lighting conditions, eliminating the need to perform experiments in the dark
•Better than aromatic azides—Bisaziridine Photoreactive Groups The group has better photostability than the traditional photoreactive cross-linker phenyl azide group under normal illumination, and long-wave ultraviolet light can activate the bisaziridine group more efficiently

Succinyl Imine-diaziridine (SDA) reagents are a new class of cross-linkers that combine proven amine reactivity chemistry with an innovative, highly efficient photochemistry based on aziridine for linking amine-containing molecules Coupled to almost any other functional group. SDA cross-linkers include six compounds with varying spacer arm lengths that are capable of cleaving cross-linked proteins in the presence or absence of charged groups for membrane permeability. Protein cross-linking is an important technique for understanding protein structure and stabilizing protein-protein interactions, and these SDA reagents expand the efficiency and range of interactions that can be explored with this method.

Typical bifunctional amine or sulfhydryl reactive cross-linkers require specific amino acid groups (such as lysine or cysteine) at the correct distance on both proteins to capture protein interactions. The SDA cross-linker allows specific labeling of one protein through the use of amine-reactive N-hydroxysuccinimide (NHS) esters and then through the use of bisazines attached to any amino acid side chain or peptide backbone of another protein. UV-activated cross-linking achieved with the pyridine moiety circumvents this limitation. Bisaziridine-based photocrosslinkers have better photostability than phenylazide-based photocrosslinkers and are easily activated using long-wavelength UV light (330-370 nm).

A wide range of bisethylene cross-linkers are available
NHS ester bisethylene derivatives (SDA, LC-SDA and SDAD) lack charged groups and Membrane permeable. This property makes it suitable for intracellular and intramembrane coupling. In contrast, Sulfo-SDA, Sulfo-LC-SDA, and Sulfo-SDAD contain negatively charged sulfate groups that increase their water solubility and reduce cell membrane permeability, thereby facilitating their extracellular use. Protein cross-linking. SDAD and Sulfo-SDAD also have disulfide bonds within the spacer that can be cleaved by reducing agents.

• Short (3.9Å) and long (12.5Å) spacer types
• Membrane permeable (NHS) and impermeable (Sulfo-NHS) types
• Non-cleavable and cleavable (disulfide spacer) types

Related products
Sulfo-SDAD（Sulfo-NHS-SS-Diaziridine）
SDA（ NHS-Diaziridine)
LC-SDA (NHS-LC-Diaziridine )