A theoretical study of the attenuation control mechanism

The attenuator control mechanism, used in a number of amino acid biosynthetic operons, is considered from a theoretical point of view. The physics of RNA hairpin-loop formation is discussed, and rules for predicting which codons in the leader peptide that will affect operon expression are suggested. Manabe's (1981) stochastic model for the attenuator mechanism is used to analyse a number of known attenuators, showing a need for a “polymerase pause-site” in most of the attenuators, and providing some quantitative arguments in favour of the use of unusual codons in the control region.