Reconstruction of de novo pathway for synthesis of UDP-glucuronic acid and UDP-xylose from intrinsic UDP-glucose in Saccharomyces cerevisiae

FEBS J. 2006 Jun;273(12):2645-57. doi: 10.1111/j.1742-4658.2006.05281.x.

Abstract

UDP-D-glucuronic acid and UDP-D-xylose are required for the biosynthesis of glycosaminoglycan in mammals and of cell wall polysaccharides in plants. Given the importance of these glycans to some organisms, the development of a system for production of UDP-D-glucuronic acid and UDP-D-xylose from a common precursor could prove useful for a number of applications. The budding yeast Saccharomyces cerevisiae lacks an endogenous ability to synthesize or consume UDP-D-glucuronic acid and UDP-D-xylose. However, yeast have a large cytoplasmic pool of UDP-D-glucose that could be used to synthesize cell wall beta-glucan, as a precursor of UDP-D-glucuronic acid and UDP-D-xylose. Thus, if a mechanism for converting the precursors into the end-products can be identified, yeast may be harnessed as a system for production of glycans. Here we report a novel S. cerevisiae strain that coexpresses the Arabidopsis thaliana genes UGD1 and UXS3, which encode a UDP-glucose dehydrogenase (AtUGD1) and a UDP-glucuronic acid decarboxylase (AtUXS3), respectively, which are required for the conversion of UDP-D-glucose to UDP-D-xylose in plants. The recombinant yeast strain was capable of converting UDP-D-glucose to UDP-D-glucuronic acid, and UDP-D-glucuronic acid to UDP-D-xylose, in the cytoplasm, demonstrating the usefulness of this yeast system for the synthesis of glycans. Furthermore, we observed that overexpression of AtUGD1 caused a reduction in the UDP-D-glucose pool, whereas coexpression of AtUXS3 and AtUGD1 did not result in reduction of the UDP-D-glucose pool. Enzymatic analysis of the purified hexamer His-AtUGD1 revealed that AtUGD1 activity is strongly inhibited by UDP-D-xylose, suggesting that AtUGD1 maintains intracellular levels of UDP-D-glucose in cooperation with AtUXS3 via the inhibition of AtUGD1 by UDP-D-xylose.

Publication types

  • Research Support, Non-U.S. Gov't

MeSH terms

  • Arabidopsis Proteins / genetics
  • Arabidopsis Proteins / metabolism*
  • Carboxy-Lyases / genetics
  • Carboxy-Lyases / metabolism
  • Cloning, Molecular
  • Cytoplasm / metabolism
  • Gene Expression Regulation, Plant
  • Kinetics
  • Mass Spectrometry
  • Models, Biological
  • Recombinant Proteins / genetics
  • Recombinant Proteins / metabolism
  • Saccharomyces cerevisiae / cytology
  • Saccharomyces cerevisiae / genetics
  • Saccharomyces cerevisiae / metabolism*
  • Uridine Diphosphate Glucose / metabolism*
  • Uridine Diphosphate Glucose Dehydrogenase / genetics
  • Uridine Diphosphate Glucose Dehydrogenase / metabolism*
  • Uridine Diphosphate Glucuronic Acid / biosynthesis*
  • Uridine Diphosphate Xylose / biosynthesis*

Substances

  • Arabidopsis Proteins
  • Recombinant Proteins
  • Uridine Diphosphate Glucuronic Acid
  • Uridine Diphosphate Xylose
  • UGD1 protein, Arabidopsis
  • Uridine Diphosphate Glucose Dehydrogenase
  • Carboxy-Lyases
  • UDPglucuronate decarboxylase
  • Uridine Diphosphate Glucose