Protein flexibility B factor

Question

[Neuls]

I was asked to search for epitopes in a protein and assess if they were flexible. To my knowledge i have mainly one possibility which would be doing MD and calculate the rmsf and rmsd for the region of insterest (I have no clue about time scale.. im short on computational power)

However, i wonder if the B factor present in the PDB file can give you a clue about how flexible protein regions are. If so, which valueos of B factor would u consider?

Thanks,