Accepted name: N-terminal methionine Nα-acetyltransferase NatE
Reaction: (1) acetyl-CoA + an N-terminal-L-methionyl-L-alanyl-[protein] = an N-terminal-Nα-acetyl-L-methionyl-L-alanyl-[protein] + CoA
(2) acetyl-CoA + an N-terminal-L-methionyl-L-seryl-[protein] = an N-terminal-Nα-acetyl-L-methionyl-L-seryl-[protein] + CoA
(3) acetyl-CoA + an N-terminal-L-methionyl-L-valyl-[protein] = an N-terminal-Nα-acetyl-L-methionyl-L-valyl-[protein] + CoA
(4) acetyl-CoA + an N-terminal-L-methionyl-L-threonyl-[protein] = an N-terminal-Nα-acetyl-L-methionyl-L-threonyl-[protein] + CoA
(5) acetyl-CoA + an N-terminal-L-methionyl-L-lysyl-[protein] = an N-terminal-Nα-acetyl-L-methionyl-L-lysyl-[protein] + CoA
(6) acetyl-CoA + an N-terminal-L-methionyl-L-leucyl-[protein] = an N-terminal-Nα-acetyl-L-methionyl-L-leucyl-[protein] + CoA
(7) acetyl-CoA + an N-terminal-L-methionyl-L-phenylalanyl-[protein] = an N-terminal-Nα-acetyl-L-methionyl-L-phenylalanyl-[protein] + CoA
(8) acetyl-CoA + an N-terminal-L-methionyl-L-tyrosyl-[protein] = an N-terminal-Nα-acetyl-L-methionyl-L-tyrosyl-[protein] + CoA
Other name(s): NAA50 (gene name); NAT5; SAN
Systematic name: acetyl-CoA:N-terminal-Met-Ala/Ser/Val/Thr/Lys/Leu/Phe/Tyr-[protein] Met-Nα-acetyltransferase
Comments: N-terminal-acetylases (NATs) catalyse the covalent attachment of an acetyl moiety from acetyl-CoA to the free α-amino group at the N-terminus of a protein. This irreversible modification neutralizes the positive charge at the N-terminus, makes the N-terminal residue larger and more hydrophobic, and prevents its removal by hydrolysis. It may also play a role in membrane targeting and gene silencing. NatE is found in all eukaryotic organisms and plays an important role in chromosome resolution and segregation. It specifically targets N-terminal L-methionine residues attached to Lys, Val, Ala, Tyr, Phe, Leu, Ser, and Thr. There is some substrate overlap with EC, N-terminal methionine Nα-acetyltransferase NatC. In addition, the acetylation of Met followed by small residues such as Ser, Thr, Ala, or Val suggests a kinetic competition between NatE and EC, methionyl aminopeptidase. The enzyme also has the activity of EC, histone acetyltransferase, and autoacetylates several of its own lysine residues.
1.  Hou, F., Chu, C.W., Kong, X., Yokomori, K. and Zou, H. The acetyltransferase activity of San stabilizes the mitotic cohesin at the centromeres in a shugoshin-independent manner. J. Cell Biol. 177 (2007) 587–597. [PMID: 17502424]
2.  Pimenta-Marques, A., Tostoes, R., Marty, T., Barbosa, V., Lehmann, R. and Martinho, R.G. Differential requirements of a mitotic acetyltransferase in somatic and germ line cells. Dev. Biol. 323 (2008) 197–206. [PMID: 18801358]
3.  Evjenth, R., Hole, K., Karlsen, O.A., Ziegler, M., Arnesen, T. and Lillehaug, J.R. Human Naa50p (Nat5/San) displays both protein Nα- and Nε-acetyltransferase activity. J. Biol. Chem. 284 (2009) 31122–31129. [PMID: 19744929]
4.  Van Damme, P., Hole, K., Gevaert, K. and Arnesen, T. N-terminal acetylome analysis reveals the specificity of Naa50 (Nat5) and suggests a kinetic competition between N-terminal acetyltransferases and methionine aminopeptidases. Proteomics 15 (2015) 2436–2446. [PMID: 25886145]
[EC created 1989 as EC, part transferred 2016 to EC]

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