Binding of biotinylated protein or RNA to streptavidin beads

Biotinylated RNA (see Section 2.3.2 for preparation) or proteina Streptavidine-agarose beads (BRL)b Blocking buffer 20 mM HEPES-KOH, pH 7.6 300 mM KC1 0.01% Nonidet P-40 

coli bulk tRNA (O.lmg/ml RNase free from Boehringer Mannheim) 

The beads prepared in this blocking procedure will suffice for 4-5 analytical affinity purification experiments. 

Add 100 pi of a 50% suspension of streptavidin-agarose beads to an Eppendorf tube.b 

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