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Discovery and Characterization of FMN-Binding β-Glucuronidases in the Human Gut Microbiome

Journal Article · · Journal of Molecular Biology

The human gut microbiota encodes β-glucuronidases (GUSs) that play key roles in health and disease via the metabolism of glucuronate-containing carbohydrates and drugs. Hundreds of putative bacterial GUS enzymes have been identified by metagenomic analysis of the human gut microbiome, but less than 10% have characterized structures and functions. Here in this paper we describe a set of unique gut microbial GUS enzymes that bind flavin mononucleotide (FMN). First, we show using mass spectrometry, isothermal titration calorimetry, and x-ray crystallography that a purified GUS from the gut commensal microbe Faecalibacterium prausnitzii binds to FMN on a surface groove located 30 Å away from the active site. Second, utilizing structural and functional data from this FMN-binding GUS, we analyzed the 279 unique GUS sequences from the Human Microbiome Project database and identified 14 putative FMN-binding GUSs. We characterized four of these hits and solved the structure of two, the GUSs from Ruminococcus gnavus and Roseburia hominis, which confirmed that these are FMN binders. Third, binding and kinetic analysis of the FMN-binding site mutants of these five GUSs show that they utilize a conserved site to bind FMN that is not essential for GUS activity, but can affect KM. Lastly, a comprehensive structural review of the PDB reveals that the FMN-binding site employed by these enzymes is unlike any structurally characterized FMN binders to date. These findings reveal the first instance of an FMN-binding glycoside hydrolase and suggest a potential link between FMN and carbohydrate metabolism in the human gut microbiota.

Research Organization:
Argonne National Laboratory (ANL), Argonne, IL (United States). Advanced Photon Source (APS)
Sponsoring Organization:
National Institutes of Health (NIH)
OSTI ID:
1497173
Journal Information:
Journal of Molecular Biology, Journal Name: Journal of Molecular Biology Journal Issue: 5 Vol. 431; ISSN 0022-2836
Publisher:
ElsevierCopyright Statement
Country of Publication:
United States
Language:
ENGLISH

References (17)

A comparison of genes involved in sphingan biosynthesis brought up to date journal August 2014
Basic local alignment search tool journal October 1990
Enzyme Function Initiative-Enzyme Similarity Tool (EFI-EST): A web tool for generating protein sequence similarity networks journal August 2015
Structure and Inhibition of Microbiome β-Glucuronidases Essential to the Alleviation of Cancer Drug Toxicity journal September 2015
An Atlas of β-Glucuronidases in the Human Intestinal Microbiome journal July 2017
A human gut microbial gene catalogue established by metagenomic sequencing journal March 2010
SignalP 4.0: discriminating signal peptides from transmembrane regions journal September 2011
Three structurally and functionally distinct β-glucuronidases from the human gut microbe Bacteroides uniformis journal October 2018
The carbohydrate-active enzymes database (CAZy) in 2013 journal November 2013
Multiple NSAID-Induced Hits Injure the Small Intestine: Underlying Mechanisms and Novel Strategies journal October 2012
Molecular Insights into Microbial β -Glucuronidase Inhibition to Abrogate CPT-11 Toxicity journal May 2013
Alleviating Cancer Drug Toxicity by Inhibiting a Bacterial Enzyme journal November 2010
Production of Exopolysaccharide by Lactobacillus rhamnosus R and Analysis of Its Enzymatic Degradation during Prolonged Fermentation journal June 2000
The Critical Roles of Polysaccharides in Gut Microbial Ecology and Physiology journal September 2017
The role of short-chain fatty acids in the interplay between diet, gut microbiota, and host energy metabolism journal July 2013
α- L -Rhamnosidase of Sphingomonas sp. R1 Producing an Unusual Exopolysaccharide of Sphingan journal January 1998
Bacterial β-glucuronidase inhibition protects mice against enteropathy induced by indomethacin, ketoprofen or diclofenac: mode of action and pharmacokinetics journal June 2013

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