I have labeled my replicating bacterial DNA with 5-Ethynyl-2'-deoxyuridine (EdU) and want to click it with biotin-PEG-3-azide followed by enrichment with magnetic streptavidin beads. So far, I have failed in doing so. I have read some articles mentioning shearing DNA before the click reaction. However, I don't know the reason for shearing DNA before "clicking" it. I want to avoid fragmenting my DNA for my downstream application. I preferably want the whole DNA intact. Anybody here who could help me understand this?