DdmDE defence system aka Helicase/UvrB N-terminal domain-containing protein from Vibrio cholerae. Molecular model of the prokaryotic Argonaute protein DdmDE that uses a DNA (deoxyribonucleic acid) guide to target and eliminate plasmid DNA. Argonaute proteins are a family of proteins involved in RNA silencing, but DdmDE is a special case that uses a DNA guide. This DNA guide directs DdmDE to a specific target plasmid DNA sequence, leading to its elimination.