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Human Nat5/San, a novel protein expressing both N‐alpha and N‐epsilon acetyltransferase activity
Author(s) -
Evjenth Rune Henrik,
Hole Kristine,
Karlsen Odd Andre,
Ziegler Mathias,
Arnesen Thomas,
Lillehaug Johan R
Publication year - 2009
Publication title -
the faseb journal
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.709
H-Index - 277
eISSN - 1530-6860
pISSN - 0892-6638
DOI - 10.1096/fasebj.23.1_supplement.lb188
Subject(s) - acetylation , acetyltransferase , histone acetyltransferase , acetyltransferases , protein subunit , lysine , biochemistry , nat , chemistry , yeast , histone acetyltransferases , histone , enzyme , amino acid , microbiology and biotechnology , biology , gene , computer network , computer science
Protein acetylation is among the most common protein modifications in eukaryotic cells. There are two types of acetylation; N‐epsilon and N‐alpha which are performed by distinct types of enzymes. N‐epsilon acetylation is performed by histone acetyltransferases (HAT) targeting epsilon‐amino group of lysines within histone proteins, a central modification in regulating gene transcription. Protein N‐terminal acetylation is performed by different N‐terminal acetyltransferase complexes (NAT). In yeast, three different NAT complexes are identified. One of them; NatA, is composed of two main subunits; Ard1p (catalytic subunit) and Nat1p (auxiliary subunit). Nat5p is a third subunit physically associated with NatA, but with unknown functions. We wanted to investigate the substrates of hNat5. Purified recombinant hNat5 and oligopeptide substrates were mixed and separated with reverse phase HPLC to study hNat5 acetylation activity. We found that hNat5 prefers substrates with N‐termini Met‐Leu‐Xxx‐Pro. In addition, mass spectrometry analysis of hNat5 incubated with acetyl CoA, demonstrated that hNat5 has autoacetylation activity. Autoacetylation and acetylation of other subset of substrates indicate activity similar to HAT. In conclusion, we here present a novel human acetyltransferase, hNat5 with a dual activity targeting both N‐terminal (NAT activity) and lysine ‐ amino groups (HAT activity).