Multivalent Binding

Hello All,

I am very new to SPR. I have been using CM5 chip (BIA 2000) and immobilized the ligand. The ligand is a hexamer. Literature suggests that one molecule of analyte binds to the hexamer or 6 molecules of ligand. Is it possible to analyze this using SPR. What precautions should I take before passing the analyte.

Thanks a lot..

Hi,

I am a little confused. Do you mean that one ligand molecule (a hexamer) can bind 6 analyte molecules or that to need the ligand hexamer conformation to bind one analyte molecule.

Can you quote the publication?

Kind regards
Arnoud

Hello,
Sorry for the late answer and thanks a lot for you prompt reply. Yes, My ligand is a hexamer which binds to single molecule of analyte. (Reference : Alternating translocation of protein substrates from both ends of ClpXP protease www.ncbi.nlm.nih.gov/pmc/articles/PMC126282/ )
Could you please guide me how to fit the data with existing model or precautions which are clearly needed with this kind of system.

Thanks a lot

With Regards,
Deepti

Hi Deepti,

When the ligand is a hexamer, binding only one analyte molecule, in SPR you model that as a 1:1 interaction. In general, the ligand is treated as if it is monovalent. For instance an IgG is bivalent but from the SPR perspective both binding sites are independent. In your case you need a hexamer to form one binding site and therefore you should model is as a 1:1 interaction.

For some extra information on the parameters look at
www.sprpages.nl/data-fitting/models

Kind regards
Arnoud