Structure of isoprene synthase illuminates the chemical mechanism of teragram atmospheric carbon emission

J Mol Biol. 2010 Sep 17;402(2):363-73. doi: 10.1016/j.jmb.2010.07.009. Epub 2010 Jul 17.

Abstract

The X-ray crystal structure of recombinant PcISPS (isoprene synthase from gray poplar hybrid Populus×canescens) has been determined at 2.7 Å resolution, and the structure of its complex with three Mg(2+) and the unreactive substrate analogue dimethylallyl-S-thiolodiphosphate has been determined at 2.8 Å resolution. Analysis of these structures suggests that the generation of isoprene from substrate dimethylallyl diphosphate occurs via a syn-periplanar elimination mechanism in which the diphosphate-leaving group serves as a general base. This chemical mechanism is responsible for the annual atmospheric emission of 100 Tg of isoprene by terrestrial plant life. Importantly, the PcISPS structure promises to guide future protein engineering studies, potentially leading to hydrocarbon fuels and products that do not rely on traditional petrochemical sources.

MeSH terms

  • Alkyl and Aryl Transferases / chemistry*
  • Alkyl and Aryl Transferases / metabolism
  • Butadienes / metabolism*
  • Chimera
  • Coenzymes / chemistry*
  • Coenzymes / metabolism
  • Crystallography, X-Ray
  • Enzyme Inhibitors / chemistry*
  • Enzyme Inhibitors / metabolism
  • Hemiterpenes / chemistry*
  • Hemiterpenes / metabolism*
  • Magnesium / chemistry*
  • Magnesium / metabolism
  • Models, Molecular
  • Organophosphorus Compounds / chemistry*
  • Organophosphorus Compounds / metabolism
  • Pentanes / metabolism*
  • Populus / enzymology*
  • Protein Binding
  • Protein Structure, Tertiary

Substances

  • Butadienes
  • Coenzymes
  • Enzyme Inhibitors
  • Hemiterpenes
  • Organophosphorus Compounds
  • Pentanes
  • isoprene
  • 3,3-dimethylallyl pyrophosphate
  • Alkyl and Aryl Transferases
  • isoprene synthase
  • Magnesium

Associated data

  • PDB/3N0F
  • PDB/3N0G