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J Bacteriol. 2017 Jul 11;199(15). pii: e00860-16. doi: 10.1128/JB.00860-16. Print 2017 Aug 1.

Polysaccharide Utilization Loci: Fueling Microbial Communities.

Author information

1
Agriculture and Agri-Food Canada, Lethbridge Research and Development Centre, Lethbridge, Alberta, Canada.
2
Michael Smith Laboratories, Department of Chemistry, Department of Biochemistry and Molecular Biology, and Department of Botany, University of British Columbia, Vancouver, British Columbia, Canada.
3
Agriculture and Agri-Food Canada, Lethbridge Research and Development Centre, Lethbridge, Alberta, Canada wade.abbott@agr.gc.ca brumer@msl.ubc.ca.
4
GlycoNet, The Canadian Glycomics Network‡.
5
Michael Smith Laboratories, Department of Chemistry, Department of Biochemistry and Molecular Biology, and Department of Botany, University of British Columbia, Vancouver, British Columbia, Canada wade.abbott@agr.gc.ca brumer@msl.ubc.ca.

Abstract

The complex carbohydrates of terrestrial and marine biomass represent a rich nutrient source for free-living and mutualistic microbes alike. The enzymatic saccharification of these diverse substrates is of critical importance for fueling a variety of complex microbial communities, including marine, soil, ruminant, and monogastric microbiota. Consequently, highly specific carbohydrate-active enzymes, recognition proteins, and transporters are enriched in the genomes of certain species and are of critical importance in competitive environments. In Bacteroidetes bacteria, these systems are organized as polysaccharide utilization loci (PULs), which are strictly regulated, colocalized gene clusters that encode enzyme and protein ensembles required for the saccharification of complex carbohydrates. This review provides historical perspectives and summarizes key findings in the study of these systems, highlighting a critical shift from sequence-based PUL discovery to systems-based analyses combining reverse genetics, biochemistry, enzymology, and structural biology to precisely illuminate the molecular mechanisms underpinning PUL function. The ecological implications of dynamic PUL deployment by key species in the human gastrointestinal tract are explored, as well as the wider distribution of these systems in other gut, terrestrial, and marine environments.

KEYWORDS:

Bacteroidetes; carbohydrate; carbohydrate-active enzymes (CAZymes); metabolism; microbiome; polysaccharide utilization loci (PULs); polysaccharides; symbiosis

PMID:
28138099
PMCID:
PMC5512228
DOI:
10.1128/JB.00860-16
[Indexed for MEDLINE]
Free PMC Article

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