The extent to which different molecules interact with a single partner immobilized on a sensor surface reveals the specificity of an interaction, and information on dissociation constants is obtained. Apart from the need to immobilise the partner on a chip surface, the method is artefact-free and does not require the use of any labelling.
The Biacore X100 instrument (product release 2005; purchased in 2008) was funded by a CIF bid made jointly between Biochemical Engineering (Dr Paul Dalby) and Structural and Molecular Biology (Prof Steve Perkins). The instrument software and hardware has been continuously upgraded to the currently-available specification.
It should be noted that we possess analytical ultracentrifuge equipment which makes complementary measurements in solution to those on a surface from the Biacore (AUC), and likewise dual polarisation interferometry (DPI).
Room SB16 in the Darwin Subbasement
- Biacore X100 surface plasmon resonance.
- Linux server with 4 Tb disk capacity for Biacore data archive, and multiuser PC's for data analyses
1) Specificity, where simple yes/no answers are required for a wide variety of applications:
Eg: search for binding partners, test for cross-reactivity, look for activity after purification.
2) Kinetics and rates of reaction. The kinetics of an interaction, i.e. the rates of complex formation (ka) and dissociation (kd), can be determined from the information in a sensorgram.
If binding occurs as sample passes over a prepared sensor surface, the response in the sensorgram increases. If equilibrium is reached a constant signal will be seen. Replacing sample with buffer causes the bound molecules to dissociate and the response decreases.
Biacore evaluation software generates the values of ka and kd by fitting the data to interaction models.
3) Affinity: the strength of binding. The affinity of an interaction is determined from the level of binding at equilibrium (seen as a constant signal) as a function of sample concentration. Affinity can also be determined from kinetic measurements. For a simple 1:1 interaction, the equilibrium constant KD is the ratio of the kinetic rate constants, kd/ka. Other types of interactions can be analyzed.
Negotiable. To all UCL staff and groups £70 per day of access to Biacore X100 Surface Plasmon Resonance Instrument from 1 January 2018. Users should purchase their own sensor chips. Please contact us if you need costs for a grant application.
We anticipate that either we will run the samples for you, or users will have to arrange for proper training from Biacore. Data processing is the users' responsibility and we can usually provide users with either access multiuser PC's or with their data and the necessary software. The manuals are available as PDF files.