JoVE - Journal of Visualized Experiments
JoVE Visualize
Research Domains
View All

Contact Us

Phage-encoded enzymes found in Acinetobacter baumannii convert pseudaminic acid to 8-epipseudaminic acid

  • 1Centre for Immunology and Infection Control, School of Biomedical Sciences, Faculty of Health, Queensland University of Technology, Brisbane, QLD, Australia.
  • 2Department of Chemical Sciences, University of Napoli Federico II Complesso Universitario Monte Santangelo, Via Cintia 4, I-80126, Naples, Italy.
  • 3School of Life and Environmental Science, The University of Sydney, Sydney, NSW, Australia. ruth.hall@sydney.edu.au.
  • 4Centre for Immunology and Infection Control, School of Biomedical Sciences, Faculty of Health, Queensland University of Technology, Brisbane, QLD, Australia. j.kenyon@griffith.edu.au.
  • 5School of Pharmacy and Medical Sciences, Health Group, Griffith University, Gold Coast Campus, Southport, QLD, Australia. j.kenyon@griffith.edu.au.
  • 6Institute for Biomedicine and Glycomics, Griffith University, Gold Coast Campus, Southport, QLD, Australia. j.kenyon@griffith.edu.au.
+

|

May 5, 2025

Abstract

The nonulosonic acid 8-epipseudaminic acid was discovered only recently in two Acinetobacter baumannii strains but the genes responsible for conversion of pseudaminic acid to its 8-epimer were not found at the K locus. Here, we use a pan-genome approach to identify a pair of carbohydrate biosynthesis genes, epaA and epaB, and demonstrate using NMR analysis of the capsular polysaccharide that they encode enzymes able to convert pseudaminic acid to its 8-epimer. Via an extensive survey of available A. baumannii genomes, we show that the epaA and epaB genes are present in 17 different Caudoviricetes class prophages. The prophages are in genomes that carry different capsule biosynthesis loci from isolates recovered in several different countries. The presence of epaA and epaB genes in A. baumannii isolates that are able to produce pseudaminic acid leads to modification of capsular polysaccharides that decorate their cell surface with potential implications for capsule typing and capsule-targeting therapies.

Keywords:

Related Concept Videos

Phase II Reactions: Acetylation Reactions 01:24

135

Acetylation, a phase II biotransformation reaction, introduces an acetyl group to drugs or their metabolites. Acetyltransferase enzymes facilitate this reaction, which resembles α-amino acid conjugation due to the addition of a functional group to the drug molecule.
The substrates for acetylation are typically drugs or their metabolites with an amino, sulfonamide, or hydrazine functional group. Acetylation can occur at several points in the drug molecule, including primary, secondary, and...

Acid Halides to Amides: Aminolysis 01:07

2.5K

Aminolysis is a nucleophilic acyl substitution reaction, where ammonia or amines act as nucleophiles to give the substitution product. Acid halides react with ammonia, primary amines, and secondary amines to yield primary, secondary, and tertiary amides, respectively.
In the first step of the aminolysis mechanism, the amine attacks the carbonyl carbon of the acyl chloride to form a tetrahedral intermediate. In the second step, the carbonyl group is re-formed with the elimination of a chloride...

Lysogenic Cycle of Bacteriophages 00:43

61.4K

In contrast to the lytic cycle, phages infecting bacteria via the lysogenic cycle do not immediately kill their host cell. Instead, they combine their genome with the host genome, allowing the bacteria to replicate the phage DNA along with the bacterial genome. The incorporated copy of the phage genome is called the prophage. Some prophages can re-activate and enter the lytic cycle. This often occurs in response to a perturbation, such as DNA damage, but can also transpire in the absence of...

Amines to Amides: Acylation of Amines 01:19

2.3K

Various carboxylic acid derivatives (such as acid chlorides, esters, and anhydrides) can be used for the acylation of amines to yield amides. The reaction requires two equivalents of amines. The first amine molecule functions as a nucleophile and attacks the carbonyl carbon to produce a tetrahedral intermediate. This is followed by the loss of the leaving group and restoration of the C=O bond.
Next, the second equivalent of amine serves as a Brønsted base and deprotonates the quaternary...