Dual cytosine modification through hydroxylation and arabinofuranosylation in phages.

Coliphage HY126 encodes a novel dual cytosine modification system involving hydroxylation and diarabinofuranosylation, creating a unique DNA modification with two arabinofuranose units.

• Why it matters: Understanding phage DNA modifications is crucial because they help phages evade host defenses and influence their infectivity. This work fills a gap by revealing a previously uncharacterized enzymatic pathway in phages.
• What they did: The researchers identified and characterized a multienzyme cascade, including AfhB, AfhE, AfhF, AfhC, and AfhG, which together hydroxylate deoxycytidine and add two arabinofuranose groups to DNA in a two-step process.
• The result: This discovery uncovers a unique enzymatic strategy for DNA modification in phages, advancing knowledge of phage-host interactions and potentially informing biotechnological applications involving DNA modifications.