Protein Acetylation in Archaea, Bacteria, and Eukaryotes

Abstract

Proteins can be acetylated at the alpha-amino group of the N-terminal amino acid (methionine or the penultimate amino acid after methionine removal) or at the epsilon-amino group of internal lysines. In eukaryotes the majority of proteins are N-terminally acetylated, while this is extremely rare in bacteria. A variety of studies about N-terminal acetylation in archaea have been reported recently, and it was revealed that a considerable fraction of proteins is N-terminally acetylated in haloarchaea and Sulfolobus, while this does not seem to apply for methanogenic archaea. Many eukaryotic proteins are modified by differential internal acetylation, which is important for a variety of processes. Until very recently, only two bacterial proteins were known to be acetylation targets, but now 125 acetylation sites are known for E. coli. Knowledge about internal acetylation in archaea is extremely limited; only two target proteins are known, only one of which—Alba—was used to study differential acetylation. However, indications accumulate that the degree of internal acetylation of archaeal proteins might be underestimated, and differential acetylation has been shown to be essential for the viability of haloarchaea. Focused proteomic approaches are needed to get an overview of the extent of internal protein acetylation in archaea.

Post-translational regulation of a Porphyromonas gingivalis regulator

“…The findings that pat (PGN_1185) was co-transcribed with rprY (PGN_1186) and had the same transcriptional start (Figure 1) prompted the present study to determine whether acetylation, a post-translational modification, altered the regulatory functions of RprY in strain ATCC 33277. Acetylation was originally identified as a modification of histone proteins in eukaryotes, but recently similarly acetylated proteins were identified in prokaryotes reviewed by Soppa [17] and Jones and O’Connor [18]. Nε-Lysine acetylation of proteins is effected by acetyl CoA synthase and a Gcn-5-like acetyltransferase (GNAT) that uses acetyl CoA as the acetyl donor with the concomitant release of CoA [19].…”

Two-component signal transduction systems in oral bacteria

“…However, the gene adjacent to rprY encodes a protein acetyltransferase ( pat : PGN_1185 in ATCC 33277); the pat and rprY genes have the same transcription start site and are co-transcribed [47]. Based on protein homology, Pat is a GCN5-related acetyltransferase (GNAT), proteins that were originally identified for their role in modification of eukaryotic histone proteins; however, recently, similarly acetylated proteins were identified in prokaryotes [48,49]. N ε -Lysine acetylation of proteins is effected by acetyl CoA synthase and a GNAT that uses acetyl CoA as the acetyl donor with the concomitant release of CoA [50].…”

Implications for the evolution of eukaryotic amino-terminal acetyltransferase (NAT) enzymes from the structure of an archaeal ortholog

“…These structures and their accompanying biochemical characterization have provided significant insight into the mechanisms of substrate specificity and catalysis used by NAT enzymes. Interestingly, although NatA and NatE both catalyze α-amino group acetylation, they use unique catalytic strategies and substantially different substrate amino-terminal residue binding pockets to achieve sequence-based substrate specificity.Although only six amino-terminally acetylated proteins have been identified in Escherichia coli, large-scale proteomics studies of three different archaeal species revealed that ∼14-29% of all proteins isolated are acetylated at their amino terminus (17)(18)(19)(20). Analysis of the thermophilic archaea Sulfolobus solfataricus genome resulted in the identification of a protein with 37% sequence identity to human NAA10 that is believed to be the only NAT in this species (21).…”

“…Although only six amino-terminally acetylated proteins have been identified in Escherichia coli, large-scale proteomics studies of three different archaeal species revealed that ∼14-29% of all proteins isolated are acetylated at their amino terminus (17)(18)(19)(20). Analysis of the thermophilic archaea Sulfolobus solfataricus genome resulted in the identification of a protein with 37% sequence identity to human NAA10 that is believed to be the only NAT in this species (21).…”