 On the other hand, the tag may also not be sufficiently exposed to the affinity beads, hence skewing the results.There may also be a possibility of a cleavage of the proteins by the TEV protease, although this is unlikely to be frequent given the high specificity of the TEV protease.As this method involves at least 2 rounds of washing, it may not be suitable for screening transient protein interactions, unlike the yeast two-hybrid method or "in vivo" crosslinking with photo-reactive amino acid analogs.