Microbiologists have identified an unexpected role for PNGaseA, an enzyme produced by some infant-associated Bifidobacterium bacteria. The enzyme helps these microbes access particular sugars in human breast milk, nutrients believed to support the development of a typical infant gut microbiota.
The findings, published in Nature Communications on November 2, show that PNGaseA releases sugars attached to short protein chains. Once removed from those chains, the sugars become available as a food source for the bacteria.
PNGaseA is generally associated with processes in animals and plants, including the recycling of cellular components. The study led by Dr. Lucy Crouch of the University of Birmingham found that some Bifidobacterium species use the enzyme to feed on these breast milk nutrients.
The researchers also found that PNGaseA targets sugars carried on short protein chains. These nutrients are present in human breast milk but not in infant formula, highlighting components that may be important for establishing a healthy early-life microbiome.
Crouch said the discovery demonstrates the complexity of the microbial community in breastfed infants. She added that identifying the components that support beneficial bacteria could help researchers develop infant formulas that more closely reproduce the functions of human milk.
The team also determined the structure of a PNGase enzyme bound to an N-glycopeptide. According to Ramón Hurtado-Guerrero, a professor at the University of Zaragoza and study co-author, this structure shows how the enzyme recognizes both the sugar and the attached protein fragment. It may also provide clues about how related PNGase enzymes identify their targets.
The researchers said that characterizing how PNGaseA makes specific breast milk nutrients available could improve understanding of how human milk shapes the infant microbial community. The work may also contribute to the development of future prebiotics for formulas intended for babies without access to breast milk.
The study, titled “Structural basis for N-glycopeptide preference in an infant-derived Bifidobacterium bifidum PNGaseA,” was published in Nature Communications. DOI: 10.1038/s41467-026-78972-1.
Sources: Phys.org.