Capsule-Targeting Depolymerases Derived from Acinetobacter baumannii Prophage Regions.

Area of Science:

• Microbiology
• Biochemistry
• Genomics

Background:

• Acinetobacter baumannii is a significant opportunistic pathogen.
• Bacterial capsular polysaccharides (CPSs) are key virulence factors.
• Prophages are integrated viral elements within bacterial genomes.

Purpose of the Study:

• To identify and characterize prophage-encoded depolymerases from Acinetobacter baumannii.
• To assess the enzymatic activity and specificity of these depolymerases.
• To evaluate their therapeutic potential against Acinetobacter baumannii infections.

Main Methods:

• Bioinformatic prediction of depolymerases from Acinetobacter baumannii prophage regions.
• Recombinant production and purification of identified depolymerases.
• Enzymatic assays to determine specificity for Acinetobacter baumannii capsular polysaccharides (K1 and K92 types).
• In vivo efficacy testing using Galleria mellonella infection models.

Main Results:

• Several prophage-derived depolymerases were identified, exhibiting multi-domain structures.
• These enzymes demonstrated specificity for Acinetobacter baumannii K1 and K92 capsular polysaccharides.
• The depolymerases function as glycosidases, hydrolyzing CPS into monomers and oligomers.
• Recombinant depolymerases significantly reduced larval mortality in Galleria mellonella models.

Conclusions:

• Prophage-derived depolymerases are prevalent in Acinetobacter baumannii genomes.
• These enzymes possess polysaccharide-degrading activity and are effective against specific capsular types.
• The characterized depolymerases represent promising candidates for developing novel antibacterials against Acinetobacter baumannii.