Biosynthesis of UDP-glucuronic acid and UDP-galacturonic acid in Bacillus cereus subsp. cytotoxis NVH 391-98

Bryan Richard Broach, Xiaogang Gu, Maor Bar-Peled

Research output: Contribution to journalArticle

17 Citations (Scopus)

Abstract

The food borne pathogen Bacillus cereus produces uronic acid-containing glycans that are secreted in a shielding biofilm environment, and certain alkaliphilic Bacillus deposit uronate-glycan polymers in the cell wall when adapting to alkaline environments. The source of these acidic sugars is unknown and, in the present study, we describe the functional identification of an operon in Bacillus cerues subsp. cytotoxis NVH 391-98 that comprises genes involved in the synthesis of UDP-uronic acids in Bacillus spp. Within the operon, a UDP-glucose 6-dehydrogenase converts UDP-glucose in the presence of NAD + to UDP-glucuronic acid and NADH, and a UDP-GlcA 4-epimerase (UGlcAE) converts UDP-glucuronic acid to UDP-galacturonic acid. Interestingly, in vitro, both enzymes can utilize the TDP-sugar forms as well, albeit at lower catalytic efficiency. Unlike most of the very few bacterial 4-epimerases that have been characterized, which are promiscuous, the B. cereus UGlcAE enzyme is very specific and cannot use UDP-glucose, UDP-N-acetylglucosamine, UDP-N-acetylglucosaminuronic acid or UDP-xylose as substrates. Size exclusion chromatography suggests that UGlcAE is active as a monomer, unlike the dimeric form of plant enzymes; the Bacillus UDP-glucose 6-dehydrogenase is also found as a monomer. Phylogenic analysis further suggests that the Bacillus UGlcAE may have evolved separately from other bacterial and plant epimerases. Our results provide insight into the formation and function of uronic acid-containing glycans in the lifecycle of B. cereus and related species containing homologous operons, as well as a basis for determining the importance of these acidic glycans. We also discuss the ability to target UGlcAE as a drug candidate.

Original languageEnglish (US)
Pages (from-to)100-112
Number of pages13
JournalFEBS Journal
Volume279
Issue number1
DOIs
StatePublished - Jan 1 2012

Fingerprint

Uridine Diphosphate Glucuronic Acid
Bacillus cereus
Racemases and Epimerases
Uridine Diphosphate
Biosynthesis
Bacilli
Bacillus
Uridine Diphosphate Glucose
Uronic Acids
Polysaccharides
Uridine Diphosphate Glucose Dehydrogenase
Operon
NAD
Uridine Diphosphate Xylose
Enzymes
Monomers
Uridine Diphosphate N-Acetylglucosamine
Size exclusion chromatography
Biofilms
Pathogens

Keywords

  • Bacillus
  • UDP-galacturonic acid
  • UDP-glucuronic acid
  • alkalinity
  • biofilm

ASJC Scopus subject areas

  • Biochemistry
  • Cell Biology
  • Molecular Biology

Cite this

Biosynthesis of UDP-glucuronic acid and UDP-galacturonic acid in Bacillus cereus subsp. cytotoxis NVH 391-98. / Broach, Bryan Richard; Gu, Xiaogang; Bar-Peled, Maor.

In: FEBS Journal, Vol. 279, No. 1, 01.01.2012, p. 100-112.

Research output: Contribution to journalArticle

Broach, Bryan Richard ; Gu, Xiaogang ; Bar-Peled, Maor. / Biosynthesis of UDP-glucuronic acid and UDP-galacturonic acid in Bacillus cereus subsp. cytotoxis NVH 391-98. In: FEBS Journal. 2012 ; Vol. 279, No. 1. pp. 100-112.
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