Surface Plasmon Resonance (SPR)
Surface Plasmon Resonance (SPR) is a modern technique capable of providing real-time measurements of biomolecular interactions in a label-free environment with high sensitivity and throughput. The underlying principle is to immobilize a molecule (ligand) onto a sensor surface and measure the change in refractive index of the surface when another molecule (analyte) binds. We use the SPR to evaluate the kinetics of drug-target binding and also as a platform for fragment screening. Our lab has a SensiQ Pioneer SPR biosensor machine with ‘OneStep™’, a technology that exploits Taylor dispersion to generate an analyte concentration gradient that provides a high-resolution dose response in a single injection for enhanced biophysical characterization and increased throughput.
Weak Affinity Chromatography - Tandem Mass Spectroscopy (WAC-MS)
One of the most recent fragment screening approaches, WAC-MS is carried out via the covalent immobilization of the target proteins onto diol-modified silica gel in an HPLC column, using a reductive amination reaction. Immobilized proteins have been known to be stable for long periods of time, addressing one of the limiting factors in handling proteins in other fragment screening techniques. The binding affinity of the fragments to their targets will be assessed by injecting a mixture of fragments into the instrument and measuring their retention times (RTs). An attached mass spec will be used to identify and analyze the fragments. A fragment library of > 3,000 compounds has been built by rigorous filtration and selection of commercially available fragment compounds. This project is in collaboration with the pioneer of WAC-MS, Prof Sten Ohlson and his research group from Nanyang Technological University (NTU), Singapore. It is funded by an NMRC CBRG grant.
Fragment ScreeningTechniques
SensiQ Pioneer Surface Plasmon Resonance (SPR).
Used for determination of Kd’s and Fragment Screening.The only one of its kind in Singapore
Agilent 6130 LC/MS single quad
Used for WAC-MS Fragment Screening