N-Acyltransferase superfamily: Various enyzmes that characteristicly catalyze the transfer of an acyl group to a substrate; NAT (N-Acyltransferase) is a large superfamily of enzymes that mostly catalyze the transfer of an acyl group to a substrate and are implicated in a variety of functions, from bacterial antibiotic resistance to circadian rhythms in mammals. Members include GCN5-related N-Acetyltransferases (GNAT) such as Aminoglycoside N-acetyltransferases, Histone N-acetyltransferase (HAT) enzymes, and Serotonin N-acetyltransferase which catalyze the transfer of an acetyl group to a substrate. The mechanism is an ordered Bi-Bi ternary complex kinetic mechanism for most GNATs: the reaction begins with Acetyl Coenzyme A (AcCoA) binding, followed by binding of substrate, then direct transfer of the acetyl group from AcCoA to the substrate, followed by product and then CoA release. Other family members include Arginine/ornithine N-succinyltransferase, Myristoyl-CoA: protein N-myristoyltransferase, and Acyl-homoserinelactone synthase which have a similar catalytic mechanism but differ in types of acyl groups transferred. Leucyl/ph enylalanyl-tRNA-protein transferase and FemXAB nonribosomal peptidyltransferases which catalyze similar peptidyltransferase reactions are also included.

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                  ....*....|....*....|....*....|....*....|....*....
gi 688545235   47 RFTITLncDGTVRCAVLKYtVRHDQRLELLSTEVPQSHRGKGVAAHLAK 95
Cdd:pfam14542   1 RFEIRV--DGGAEVAFLTY-RRGDGVLIITHTEVPPALRGQGIASKLVK 46

GCN5-related N-acetyl-transferase; This family of GCN5-related N-acetyl-transferases bind both CoA and acetyl-CoA. They are characterized by highly conserved glycine, a cysteine residue in the acetyl-CoA binding site near the acetyl group, their small size compared with other GNATs and a lack of of an obvious substrate-binding site. It is proposed that they transfer an acetyl group from acetyl-CoA to one or more unidentified aliphatic amines via an acetyl (cysteine) enzyme intermediate. The substrate might be another macromolecule.

                          10        20        30        40
                  ....*....|....*....|....*....|....*....|....*....
gi 688545235   47 RFTITLncDGTVRCAVLKYtVRHDQRLELLSTEVPQSHRGKGVAAHLAK 95
Cdd:pfam14542   1 RFEIRV--DGGAEVAFLTY-RRGDGVLIITHTEVPPALRGQGIASKLVK 46

GCN5-related N-acetyl-transferase; This family of GCN5-related N-acetyl-transferases bind both CoA and acetyl-CoA. They are characterized by highly conserved glycine, a cysteine residue in the acetyl-CoA binding site near the acetyl group, their small size compared with other GNATs and a lack of of an obvious substrate-binding site. It is proposed that they transfer an acetyl group from acetyl-CoA to one or more unidentified aliphatic amines via an acetyl (cysteine) enzyme intermediate. The substrate might be another macromolecule.

                          10        20        30        40
                  ....*....|....*....|....*....|....*....|....*....
gi 688545235   47 RFTITLncDGTVRCAVLKYtVRHDQRLELLSTEVPQSHRGKGVAAHLAK 95
Cdd:pfam14542   1 RFEIRV--DGGAEVAFLTY-RRGDGVLIITHTEVPPALRGQGIASKLVK 46