Structure and function of human Naa60 (NatF), a Golgi-localized bi-functional acetyltransferase

Sci Rep. 2016 Aug 23:6:31425. doi: 10.1038/srep31425.

Abstract

N-terminal acetylation (Nt-acetylation), carried out by N-terminal acetyltransferases (NATs), is a conserved and primary modification of nascent peptide chains. Naa60 (also named NatF) is a recently identified NAT found only in multicellular eukaryotes. This protein was shown to locate on the Golgi apparatus and mainly catalyze the Nt-acetylation of transmembrane proteins, and it also harbors lysine N(ε)-acetyltransferase (KAT) activity to catalyze the acetylation of lysine ε-amine. Here, we report the crystal structures of human Naa60 (hNaa60) in complex with Acetyl-Coenzyme A (Ac-CoA) or Coenzyme A (CoA). The hNaa60 protein contains an amphipathic helix following its GNAT domain that may contribute to Golgi localization of hNaa60, and the β7-β8 hairpin adopted different conformations in the hNaa60(1-242) and hNaa60(1-199) crystal structures. Remarkably, we found that the side-chain of Phe 34 can influence the position of the coenzyme, indicating a new regulatory mechanism involving enzyme, co-factor and substrates interactions. Moreover, structural comparison and biochemical studies indicated that Tyr 97 and His 138 are key residues for catalytic reaction and that a non-conserved β3-β4 long loop participates in the regulation of hNaa60 activity.

Publication types

  • Research Support, Non-U.S. Gov't
  • Research Support, U.S. Gov't, Non-P.H.S.

MeSH terms

  • Acetyl Coenzyme A / chemistry*
  • Acetyl Coenzyme A / genetics
  • Acetyl Coenzyme A / metabolism
  • Acetylation
  • Golgi Apparatus / enzymology*
  • Golgi Apparatus / genetics
  • Humans
  • Lysine / chemistry
  • Lysine / genetics
  • Lysine / metabolism
  • N-Terminal Acetyltransferase F / chemistry*
  • N-Terminal Acetyltransferase F / genetics
  • N-Terminal Acetyltransferase F / metabolism
  • Protein Domains
  • Protein Structure, Secondary
  • Structure-Activity Relationship

Substances

  • NAA60 protein, human
  • Acetyl Coenzyme A
  • N-Terminal Acetyltransferase F
  • Lysine