Intrinsic termination involves
Intrinsic termination, also termed Rho-independent, encoded purely by DNA sequence producing terminator structure in nascent RNA. Sequence comprises GC-rich inverted repeat capable forming stable hairpin stem-loop of 7-20 base pairs followed immediately by run of four to eight uridines that pair weakly with template adenines. Hairpin nucleation within polymerase exit channel causes pausing and allosteric destabilization while weak rU-dA hybrid facilitates transcript release without ATP. Mutations disrupting hairpin stability or replacing U-tract reduce termination efficiency. This architecture
Ref: Watson Molecular Biology Gene Chapter 13: Intrinsic termination hairpin U-rich tract mechanism; Berg Biochemistry Terminator hairpin stability model