I am trying to pull down a protein with its RNA binding partners using antibody-coupled Dynabeads after UV-crosslinking. However, I am using IgG coupled beads as a negative control and getting large amounts of protein and RNA coming down with these beads. My wash buffer contains detergent (NP-40), which I see is recommended for reducing non-specific binding in this sort of experiment. I have not blocked the beads, as the information I can find on Dynabeads says the effect of blocking (e.g. with BSA) is "negligible" as the Dynabead surface is hydrophobic, but maybe others have found that this is beneficial in practice? Any recommendations would be greatly appreciated. Thanks in advance.