EC 2.3.1.258     
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 2.3.1.256, 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 3.4.11.18, methionyl aminopeptidase. The enzyme also has the activity of EC 2.3.1.48, histone acetyltransferase, and autoacetylates several of its own lysine residues.
References:
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 2.3.1.258 created 1989 as EC 2.3.1.88, part transferred 2016 to EC 2.3.1.258]
 
 


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