Presence of unique glyoxalase III proteins in plants indicates the existence of shorter route for methylglyoxal detoxification

Sci Rep. 2016 Jan 6:6:18358. doi: 10.1038/srep18358.

Abstract

Glyoxalase pathway, comprising glyoxalase I (GLY I) and glyoxalase II (GLY II) enzymes, is the major pathway for detoxification of methylglyoxal (MG) into D-lactate involving reduced glutathione (GSH). However, in bacteria, glyoxalase III (GLY III) with DJ-1/PfpI domain(s) can do the same conversion in a single step without GSH. Our investigations for the presence of DJ-1/PfpI domain containing proteins in plants have indicated the existence of GLY III-like proteins in monocots, dicots, lycopods, gymnosperm and bryophytes. A deeper in silico analysis of rice genome identified twelve DJ-1 proteins encoded by six genes. Detailed analysis has been carried out including their chromosomal distribution, genomic architecture and localization. Transcript profiling under multiple stress conditions indicated strong induction of OsDJ-1 in response to exogenous MG. A member of OsDJ-1 family, OsDJ-1C, showed high constitutive expression at all developmental stages and tissues of rice. MG depletion study complemented by simultaneous formation of D-lactate proved OsDJ-1C to be a GLY III enzyme that converts MG directly into D-lactate in a GSH-independent manner. Site directed mutagenesis of Cys-119 to Alanine significantly reduces its GLY III activity indicating towards the existence of functional GLY III enzyme in rice-a shorter route for MG detoxification.

Publication types

  • Research Support, Non-U.S. Gov't

MeSH terms

  • Aldehyde Oxidoreductases / chemistry
  • Aldehyde Oxidoreductases / metabolism*
  • Amino Acid Sequence
  • Catalytic Domain
  • Chromosome Mapping
  • Gene Expression Profiling
  • Gene Expression Regulation, Plant
  • Genome, Plant
  • Inactivation, Metabolic*
  • Metabolic Networks and Pathways
  • Mutation
  • Organ Specificity / genetics
  • Oryza / classification
  • Oryza / genetics
  • Oryza / metabolism
  • Phylogeny
  • Plant Proteins / chemistry
  • Plant Proteins / metabolism
  • Plants / classification
  • Plants / genetics
  • Plants / metabolism*
  • Promoter Regions, Genetic
  • Protein Interaction Domains and Motifs
  • Pyruvaldehyde / metabolism*
  • Response Elements
  • Stress, Physiological

Substances

  • Plant Proteins
  • Pyruvaldehyde
  • Aldehyde Oxidoreductases
  • glyoxalase III