The N-end rule pathway is an ubiquitin (Ub)-dependent proteolytic system that mediates and regulates the degradation of intracellular proteins through the recognition of their N-terminal residues. NTAQ1 (also known as Nta1 in fungi) is an N-terminal amidohydrolase, which converts N-terminal Asn and Gln to the N-terminal residues Asp and Glu, the first step of the hierarchically organized N-end rule pathway []. The structure of Nta1 has been determined [].
