Twelve members of the nucleobase-ascorbate transporter (NAT) gene family have been identified in Arabidopsis thaliana []. This entry represents NAT1 and NAT2. NAT1 and NAT2 show a similar expression pattern during germination, with NAT2 being more strongly expressed [].
Ard1 and Nat1 form a stable N-terminal acetyltransferase complex and are conserved from yeast to human []. This entry represents Ard1, which is the catalytic subunit. The ARD1-NAT1 complex mediates N-terminal acetylation of nascent polypeptides that emerge from ribosomes after translation [].
This entry represents N-terminal acetyltransferase A (NatA) auxiliary subunit, which is a non-catalytic component of the NatA N-terminal acetyltransferase that catalyses acetylation of proteins beginning with Met-Ser, Met-Gly and Met-Ala. N-terminal acetylation plays a role in normal eukaryotic translation and processing, protecting against proteolytic degradation and protein turnover. NAT1 anchors ARD1 and NAT5 to the ribosome, and may present the N terminus of nascent polypeptides for acetylation [, ].
Arylamine N-acetyltransferase (NAT) facilitates the transfer of an acetyl group from acetyl coenzyme A on to a wide range of arylamine, N-hydroxyarylamines and hydrazines. Acetylation of these compounds generally results in inactivation. NAT is found in many species from Mycobacteria (Mycobacterium tuberculosis, Mycobacterium smegmatis etc) to Homo sapiens (Human). It was the first enzyme to be observed to have polymorphic activity amongst human individuals. NAT is also responsible for the inactivation of Isoniazid (a drug used to treat tuberculosis) in humans [, ]. NAT catalyses the reaction:Acetyl-coA + arylamine = coA + N-acetylarylamineNAT is the target of a common genetic polymorphism of clinical relevance in humans. The N-acetylation polymorphism is determined by low or high NAT activity in liver. NAT has been implicated in the action and toxicity of amine-containing drugs, and in the susceptibility to cancer and systematic lupus erythematosus [, , , ]. Two highly similar human genes for NAT, termed NAT1 and NAT2, encode genetically invariant and variant NAT proteins, respectively. The structure of both proteins is similar to each other and to their prokaryotic orthologues, showing three domains: the N-terminal domain is mostly α-helical, the central domain consists of nine β-strands and the C-terminal has has four anti-parallel β-strands and one α-helix. However, in the human central domain there is a specific insertion []. N-malonyltransferase FDB2 from the fungal fitopathogen Fusarium pseudograminearum also belongs to this family. It is involved in the degradation of benzoxazolinones produced by the host plant [, , ].
