The crystal structure of a hyperthermoactive exopolygalacturonase from Thermotoga maritima reveals a unique tetramer

FEBS Lett. 2009 Nov 19;583(22):3665-70. doi: 10.1016/j.febslet.2009.10.047. Epub 2009 Oct 23.


The exopolygalacturonase from Thermotoga maritima is the most thermoactive and thermostable pectinase known to date. Here we present its crystal structure at 2.05A resolution. High structural homology around the active site allowed us to propose a model for substrate binding, explaining the exo-cleavage activity and specificity for non-methylated saturated galacturonate at the non-reducing end. Furthermore, the structure reveals unique features that contribute to the formation of stable tetramers in solution. Such an oligomerization has not been observed before for polygalacturonases.

MeSH terms

  • Bacterial Proteins / chemistry*
  • Bacterial Proteins / metabolism
  • Catalytic Domain
  • Crystallization
  • Crystallography, X-Ray
  • Glycoside Hydrolases / chemistry*
  • Glycoside Hydrolases / metabolism
  • Hexuronic Acids / chemistry
  • Hexuronic Acids / metabolism
  • Hot Temperature
  • Models, Molecular
  • Protein Binding
  • Protein Multimerization*
  • Protein Structure, Quaternary
  • Protein Structure, Secondary
  • Protein Structure, Tertiary
  • Substrate Specificity
  • Thermotoga maritima / enzymology*


  • Bacterial Proteins
  • Hexuronic Acids
  • galacturonic acid
  • Glycoside Hydrolases
  • exopolygalacturonase