PMID: 27550639

Authors:

Chen JY, Liu L, Cao CL, Li MJ, Tan K, Yang X, Yun CH

Title:

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

Journal:

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(epsilon)-acetyltransferase (KAT) activity to catalyze the acetylation of lysine epsilon-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 beta7-beta8 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 beta3-beta4 long loop participates in the regulation of hNaa60 activity.