Parent Class:

EC-Numbers → 2 -- Transferases → 2.3 -- Acyltransferases → 2.3.1 -- Transferring groups other than amino-acyl groups

Synonyms: NAA50 (gene name), NAT5, SAN

Systematic Name: acetyl-CoA:N-terminal-Met-Ala/Ser/Val/Thr/Lys/Leu/Phe/Tyr-[protein] Met-N^α-acetyltransferase

Unification Links: BRENDA:2.3.1.258, ENZYME:2.3.1.258, IUBMB-ExplorEnz:2.3.1.258

Supersedes EC number: 2.3.1.88

Reaction:
acetyl-CoA + an N-terminal-L-methionyl-L-leucyl-[protein] → an N-terminal N^α-acetyl-L-methionyl-L-leucyl-[protein] + coenzyme A + H⁺,
acetyl-CoA + an N-terminal-L-methionyl-L-seryl-[protein] → an N-terminal N^α-acetyl-L-methionyl-L-seryl-[protein] + coenzyme A + H⁺,
acetyl-CoA + an N-terminal L-methionyl-L-lysyl-[protein] → an N-terminal N^α-acetyl-L-methionyl-L-lysyl-[protein] + coenzyme A + H⁺,
acetyl-CoA + an N-terminal-L-methionyl-L-alanyl-[protein] → an N-terminal-N^α-acetyl-L-methionyl-L-alanyl-[protein] + coenzyme A + H⁺,
acetyl-CoA + an N-terminal-L-methionyl-L-phenylalanyl-[protein] → an N-terminal N^α-acetyl-L-methionyl-L-phenylalanyl-[protein] + coenzyme A + H⁺,
acetyl-CoA + an N-terminal-L-methionyl-L-valyl-[protein] → an N-terminal N^α-acetyl-L-methionyl-L-valyl-[protein] + coenzyme A + H⁺,
acetyl-CoA + an N-terminal-L-methionyl-L-tyrosyl-[protein] → an N-terminal N^α-acetyl-L-methionyl-L-tyrosyl-[protein] + coenzyme A + H⁺,
acetyl-CoA + an N-terminal-L-methionyl-L-threonyl-[protein] → an N-terminal N^α-acetyl-L-methionyl-L-threonyl-[protein] + coenzyme A + H⁺

Enzymes and Genes:
N-terminal methionine N^α-acetyltransferase NatE: NAA50 ( Homo sapiens )

Summary:
N-terminal-acetylases (NATs) catalyze 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.

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 L-lysine, L-valine, L-alanine, L-tyrosine, L-phenylalanine, L-leucine, L-serine, and L-threonine. There is some substrate overlap with EC 2.3.1.256, N-terminal methionine N^α-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.

Citations: [Hou07, PimentaMarques08, Evjenth09, Van15]

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References

Evjenth09: Evjenth R, Hole K, Karlsen OA, Ziegler M, Arnesen T, Lillehaug JR (2009). "Human Naa50p (Nat5/San) displays both protein N alpha- and N epsilon-acetyltransferase activity." J Biol Chem 284(45);31122-9. PMID: 19744929

Hou07: Hou F, Chu CW, Kong X, Yokomori K, Zou H (2007). "The acetyltransferase activity of San stabilizes the mitotic cohesin at the centromeres in a shugoshin-independent manner." J Cell Biol 177(4);587-97. PMID: 17502424

PimentaMarques08: Pimenta-Marques A, Tostoes R, Marty T, Barbosa V, Lehmann R, Martinho RG (2008). "Differential requirements of a mitotic acetyltransferase in somatic and germ line cells." Dev Biol 323(2);197-206. PMID: 18801358

Van15: Van Damme P, Hole K, Gevaert K, Arnesen T (2015). "N-terminal acetylome analysis reveals the specificity of Naa50 (Nat5) and suggests a kinetic competition between N-terminal acetyltransferases and methionine aminopeptidases." Proteomics 15(14);2436-46. PMID: 25886145

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Please cite the following article in publications resulting from the use of MetaCyc: Caspi et al, Nucleic Acids Research 46(D1):D633-D639 2018
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