Threonine is one of at least 6 amino acid operons are known to be regulated by attenuation. In each a leader sequence of 150–200 bp is found upstream of the first gene in the operon. This leader sequence can assume two different secondary structures known as the terminator and the anti-terminator structure.
Threonine is one of several amino acids whose production is modulated by attenuation mechanisms. Each operon containing threonine has a regulatory sequence upstream of the first gene, which can assume either the terminator or anti-terminator conformation.