CugP is a novel ubiquitous non-GalU-type bacterial UDP-glucose pyrophosphorylase found in cyanobacteria

J Bacteriol. 2014 Jul;196(13):2348-54. doi: 10.1128/JB.01591-14. Epub 2014 Apr 11.


UDP-glucose pyrophosphorylase synthesizes UDP-glucose from UTP and glucose 1-phosphate and exists in almost all species. Most bacteria possess a GalU-type UDP-glucose pyrophosphorylase, whereas many cyanobacteria species do not. In certain cyanobacteria, UDP-glucose is used as a substrate for synthesis of exopolysaccharide cellulose in spite of the absence of GalU-type UDP-glucose pyrophosphorylase. Therefore, there should be an uncharacterized UDP-glucose pyrophosphorylase in cyanobacteria. Here, we show that all cyanobacteria possess a non-GalU-type bacterial UDP-glucose pyrophosphorylase, i.e., CugP, a novel family in the nucleotide triphosphate transferase superfamily. The expressed recombinant Synechocystis sp. strain PCC 6803 CugP had pyrophosphorylase activity that was highly specific for UTP and glucose 1-phosphate. The fact that the CugP gene cannot be deleted completely in Synechocystis sp. PCC 6803 suggests its central role as the substrate supplier for galactolipid synthesis. Galactolipids are major constituents of the photosynthetic thylakoid membrane and important for photosynthetic activity. Based on phylogenetic analysis, this CugP-type UDP-glucose pyrophosphorylase may have recently been horizontally transferred to certain noncyanobacteria.

Publication types

  • Research Support, Non-U.S. Gov't

MeSH terms

  • Amino Acid Sequence
  • Amino Acid Substitution
  • Bacterial Proteins / chemistry
  • Bacterial Proteins / genetics
  • Bacterial Proteins / metabolism*
  • Cloning, Molecular
  • Gene Expression Regulation, Bacterial / physiology*
  • Gene Expression Regulation, Enzymologic / physiology
  • Molecular Sequence Data
  • Nucleotidyltransferases / genetics
  • Nucleotidyltransferases / metabolism
  • Phylogeny
  • Recombinant Proteins / genetics
  • Recombinant Proteins / metabolism
  • Synechocystis / enzymology*
  • Synechocystis / genetics
  • Synechocystis / metabolism
  • UTP-Glucose-1-Phosphate Uridylyltransferase / genetics
  • UTP-Glucose-1-Phosphate Uridylyltransferase / metabolism*


  • Bacterial Proteins
  • Recombinant Proteins
  • Nucleotidyltransferases
  • UTP-Glucose-1-Phosphate Uridylyltransferase

Associated data

  • PDB/1H5T
  • PDB/1TZF
  • PDB/2PA4