Operon structure and cotranslational subunit association direct protein assembly in bacteria

Proximity best for building protein complexes The synthesis of protein subunits and their assembly into a fully functional complex are generally thought to be two distinct processes. Shieh et al. studied the synthesis and assembly of the luciferase complex in Escherichia coli. Organization of the luciferase subunits LuxA and LuxB side by side into an operon promotes their colocalized synthesis and assembly into an active enzyme complex. Indeed, the association between the subunits occurs as they are being synthesized on ribosomes, which helps order the sequence of subunit interactions. Science , this issue p. 678