Oligomerization transforms human APOBEC3G from an efficient enzyme to a slowly dissociating nucleic acid-binding protein

HIV-1 replication is inhibited by the enzyme APOBEC3G via two separate mechanisms. A deamination mechanism requires rapid binding and release of single-stranded DNA (ssDNA), whereas a roadblock mechanism requires slow binding. Now APOBEC3G has been shown to initially bind ssDNA with rapid on–off rates. The enzyme subsequently converts via oligomerization to a slowly dissociating binding mode, which, it is proposed, inhibits reverse transcription.