Biochemical investigation of an N‐acetyltransferase from Helicobacter pullorum

Abstract

N-acetylated sugars are often found, for example, on the lipopolysaccharides of Gram-negative bacteria, on the S-layers of Gram-positive bacteria, and on the capsular polysaccharides. Key enzymes involved in their biosynthesis are the sugar N-acetyltransferases. Here, we describe a structural and functional analysis of one such enzyme from Helicobacter pullorum, an emerging pathogen that may be associated with gastroenteritis and gallbladder and liver diseases. For this analysis, the gene BA919-RS02330 putatively encoding an N-acetyltransferase was cloned, and the corresponding protein was expressed and purified. A kinetic analysis demonstrated that the enzyme utilizes dTDP-3-amino-3,6-dideoxy-D-glucose as a substrate as well as dTDP-3-amino-3,6-dideoxy-D-galactose, albeit at a reduced rate. In addition to this kinetic analysis, a similar enzyme from Helicobacter bilis was cloned and expressed, and its kinetic parameters were determined. Seven X-ray crystallographic structures of various complexes of the H. pullorum wild-type enzyme (or the C80T variant) were determined to resolutions of 1.7 Å or higher. The overall molecular architecture of the H. pullorum N-acetyltransferase places it into the Class II left-handedβ-helix superfamily (LβH). Taken together, the data presented herein suggest that 3-acetamido-3,6-dideoxy-D-glucose (or the galactose derivative) is found on either the H. pullorum O-antigen or in another of its complex glycoconjugates. A BLAST search suggests that more than 50 non-pylori Helicobacter spp. have genes encoding N-acetyltransferases. Given that there is little information concerning the complex glycans in non-pylori Helicobacter spp. and considering their zoonotic potential, our results provide new biochemical insight into these pathogens

The footprint of gut microbiota in gallbladder cancer: a mechanistic review

“…First, LPS can be synthesized by a range of Helicobacter spp. through metabolizing dietary sugars, which is strongly associated with the development of GBC ( Van Dyke et al., 2016 ; Griffiths et al., 2021 ). Recent studies discovered that Helicobacter pullorum (H. pullorum) , an emerging pathogen that may be associated with gallbladder diseases, expresses the key enzyme N-acetyltransferase ( Griffiths et al., 2021 ).…”

“…through metabolizing dietary sugars, which is strongly associated with the development of GBC ( Van Dyke et al., 2016 ; Griffiths et al., 2021 ). Recent studies discovered that Helicobacter pullorum (H. pullorum) , an emerging pathogen that may be associated with gallbladder diseases, expresses the key enzyme N-acetyltransferase ( Griffiths et al., 2021 ). H. pullorum may metabolize carbohydrates in food by N-acetyltransferase to N-acetylated sugars, which in turn form the LPS of the cell wall.…”

“…H. pullorum may metabolize carbohydrates in food by N-acetyltransferase to N-acetylated sugars, which in turn form the LPS of the cell wall. Specifically, the food substrates metabolized by H. pullorum are dTDP-3-amino-3,6-dideoxy-d-glucose (glucose derivative) or dTDP-3-amino-3,6-dideoxy-d-galactose (galactose derivative) ( Griffiths et al., 2021 ). H. bilis and more than 50 species of non-pylori Helicobacter spp.…”

“…H. bilis and more than 50 species of non-pylori Helicobacter spp. (NPHS) also possessed genes encoding the enzyme N-acetyltransferase, which exhibited similar LPS biosynthesis functions, indicating that the bacterial metabolite LPS oncogenic pathway is common in GBC carcinogenesis ( Griffiths et al., 2021 ). Second, peptidoglycan biosynthesis is another product of bacterial metabolism of carbohydrates ( Galinier et al., 2023 ).…”

Nanopore Identification of N-Acetylation by Hydroxylamine Deacetylation (NINAHD)

“…N -Acetyl modifications, one of the most important chemical modifications in organisms, have been reported to exist in RNA, , DNA, proteins and glycans . N-Acetylation refers to the process of introducing an acetyl group to a nitrogen atom, which is usually catalyzed by the corresponding N -acetyltransferase (NAT) in living organisms. ,, N -Acetyl modifications play an irreplaceable regulatory function in gene regulation. , In recent years, accurate identification and functional analysis of N -acetyl modifications on biomacromolecules have been one of the most intensive research topics in life sciences.…”