Since the ricin B lectin domain has been shown to bind simple sugars, a good place to start would be to test a range of simple sugars for binding to the protein. This paper has some methodology you could employ to test for carbohydrate binding:

http://peds.oxfordjournals.org/content/9/4/371.full.pdf

To test simple sugars for binding, you could look for inhibition of binding of your protein to asialofetuin by the sugars, as in this paper:

http://onlinelibrary.wiley.com/doi/10.1002/jat.1136/abstract

how big is it? You can grown labelled 15N isotope labelled lectin in E.coli and do a solution NMR experiment with different conc series of sugar ligands as mentioned by Adam B shapiro. You can also SPR to see the binding kinetics between your protein and other interacting partners.

Thank you very much for your immense help. One more query. Ricin b can bind to glyco proteins as well. Can you suggest some methods for identifying those interactions?

If you don't have purified glycoproteins, you can make an extract from cells expressing the glycoprotein of interest, run it on SDS-PAGE, transfer it to a membrane, and probe the membrane with the lectin, which has been labeled in some way to allow detection. It could be labeled with a fluorescent dye, or with a radioactive tag.

Another experiment would be to covalently immobilize the lectin on a resin, then mix the resin with an extract containing the glycoprotein, or a mixture of glycoproteins, and see which proteins stick (the control is resin without lectin). This can be done by mixing the resin with SDS-PAGE sample buffer, running the proteins out on a gel, and identifying them by mass spectrometry/proteomics methods.

Thank you very much for your suggestions.

Hi Riddhi,

The responses above are elaborating on how to indentify the interactions of this gene. To identify the function, you gotta knock-out/off this gene and do a mutant analysis.

Thanks,

Aniket