Home > Protein Production & Assays > Immobilization > Strep-Tactin®XT > Strep-Tactin®XT - Molecular Interaction Analysis with SwitchSense
 
Determination of protein kinetics using switchSENSE®
 
The switchSENSE® technology of Dynamic Biosensors utilizes a novel electro-switchable biosurface to provide researchers and commercial laboratories the ability to characterize interactions between molecules in real-time. This technology is unlike existing methodologies in that it combines high sensitivity kinetics with structural information on size, shape and conformation providing a new depth and understanding of the interaction.
 
Studies are performed on a re-usable biochip, generated using familiar coupling and hybridization methods. Within this biochip, DNA levers are embedded onto a series of gold electrodes. These nanolevers serve either as target for molecular interactions themselves, or hold other interaction partners. To characterize interactions, the DRX instrument is used to bring about deliberate movement of these nanolevers by altering the voltage across the gold surface. When interactions occur, these movements are affected and in turn, used in the calculation of kinetic and biophysical information.
 
Measurement Modes
The switchSENSE® technology of Dynamic Biosensors works on the basis of electro-switchable nanolevers and thereby captures three channels of information for a new depth of interaction understanding:
 
  • The high frequency dynamic electrical switching mode probes the hydrodynamic friction and serves to analyze the size and shape of biomolecule
  • The fluorescence proximity sensing mode reveals the binding of molecules in real-time through changes in the dye`s local environment.
  • The molecular ruler mode utilizes a long-ranged energy transfer to gauge the height of the fluorophore above the surface with sub nanometer accuracy.


switchSENSE® can be used to determine a variety of parameters such as, e.g.:

  • Binding kinetics
  • Binding affinity
  • Protein diameter
  • Conformational change

Read more about switchSENSE® 

 
Products for kinetic measurements with switchSENSE®

 

Strep-Tactin®XT Kit

The Strep-Tactin®XT Kit offers an alternate and exceptionally stable immobilization method for proteins carrying a Twin-Strep-tag®.

Strep-Tactin® XT Kit (Coupling Kit, Cat.No. CK-SXT-1-B96)

 

Multi-purpose Biochips (MPC)

  • Multi-purpose chips are versatile means to analyze protein-protein, protein-small molecule, DNA/RNA-protein, and DNA/RNA-small molecule interactions.
  • By exchanging the standard complementary DNA strand, the chip design enables users to build a near infinite range of molecular structures.
  • Choose from two different nanolevers: standard DNA levers comprise 48 bp and are 16 nm long, or use 96 bp (32 nm) levers for large analytes.

 

 

Application data for Strep-Tactin®XT in switchSENSE®

Kinetics for Strep-tag®II and Twin-Strep-tag®
switchSENSE® measurements of GFP-Strep-tag®II and GFP-Twin-Strep-tag®
Data provided by Dynamic Biosensors

 

switchSENSE® measurements of GFP-Strep-tag®II and GFP-Twin-Strep-tag®:

The switchSENSE® chip was functionalized with Strep-Tactin®XT. Then the kinetic rates were determined for the two control proteins.

Comparison of affinity tags using switchSENSE®

Tag capture system

Kon [M-1s-1] Koff [s-1] KD
NTA3 - His6-tag  5 x 105  1 x 10 -3  2 nM
Strep-Tactin®XT - Strep-tag®II  2.4 x 105  3.2 x 10-3  9 nM
Strep-Tactin®XT -Twin-Strep-tag®  4.3 x 105  2.8 x 10-5

 64 pM

Data provided by Dynamic Biosensors

  • Promising functionalization method
  • Superior to His-capturing
  • Twin-Strep-tag®: almost no dissociation after 1 hour