Structural Insight into the Core of CAD

The CAD complex catalyzes the first four reactions of the pyrimidine biosynthetic pathway. CAD exhibits allosteric regulaton, both negative and positive, covalent regulation by phosphorylation, and metabolite channeling. In this issue of Structure , Moreno-Morcillo et al. (2017) show that the dihydroorotase domain plays a crucial role in the establishment of the quaternary structure of this complex.