Glucose-6-phosphate isomerase from the hyperthermophilic archaeon Methanococcus jannaschii: characterization of the first archaeal member of the phosphoglucose isomerase superfamily

Arch Microbiol. 2004 Jan;181(1):82-7. doi: 10.1007/s00203-003-0626-4. Epub 2003 Dec 4.

Abstract

ORF MJ1605, previously annotated as pgi and coding for the putative glucose-6-phosphate isomerase (phosphoglucose isomerase, PGI) of the hyperthermophilic archaeon Methanococcus jannaschii, was cloned and functionally expressed in Escherichia coli. The purified 80-kDa protein consisted of a single subunit of 45 kDa, indicating a homodimeric (alpha(2)) structure. The K(m) values for fructose 6-phosphate and glucose 6-phosphate were 0.04 mM and 1 mM, the corresponding V(max) values were 20 U/mg and 9 U/mg, respectively (at 50 degrees C). The enzyme had a temperature optimum at 89 degrees C and showed significant thermostability up to 95 degrees C. The enzyme was inhibited by 6-phosphogluconate and erythrose-4-phosphate. RT-PCR experiments demonstrated in vivo expression of ORF MJ1618 during lithoautotrophic growth of M. jannaschii on H(2)/CO(2). Phylogenetic analyses indicated that M. jannaschii PGI was obtained from bacteria, presumably from the hyperthermophile Thermotoga maritima.

Publication types

  • Research Support, Non-U.S. Gov't

MeSH terms

  • Cloning, Molecular
  • Dimerization
  • Enzyme Inhibitors / pharmacology
  • Enzyme Stability
  • Escherichia coli / genetics
  • Gene Expression Regulation, Archaeal
  • Gluconates / metabolism
  • Glucose-6-Phosphate Isomerase / chemistry
  • Glucose-6-Phosphate Isomerase / genetics*
  • Glucose-6-Phosphate Isomerase / isolation & purification
  • Glucose-6-Phosphate Isomerase / metabolism*
  • Methanococcus / enzymology*
  • Methanococcus / genetics*
  • Molecular Weight
  • Phylogeny
  • Protein Subunits / chemistry
  • Protein Subunits / metabolism
  • RNA, Messenger / analysis
  • Recombinant Proteins / genetics
  • Recombinant Proteins / isolation & purification
  • Recombinant Proteins / metabolism
  • Reverse Transcriptase Polymerase Chain Reaction
  • Sugar Phosphates / metabolism
  • Temperature
  • Transcription, Genetic

Substances

  • Enzyme Inhibitors
  • Gluconates
  • Protein Subunits
  • RNA, Messenger
  • Recombinant Proteins
  • Sugar Phosphates
  • erythrose 4-phosphate
  • Glucose-6-Phosphate Isomerase
  • 6-phosphogluconic acid