The C-terminal domain of HPII catalase is a member of the type I glutamine amidotransferase superfamily

Monica M. Horvath, Nick V. Grishin

Research output: Contribution to journalArticlepeer-review

32 Scopus citations


Discovering distant evolutionary relationships between proteins requires detecting subtle similarities. Here we use a combination of sequence and structure analysis to show that the C-terminal domain of Escherichia coli HPII catalase with available spatial structure is a divergent member of the type I glutamine amidotransferase (GAT) superfamily. GAT-containing proteins include many biosynthetic enzymes such as E. coli carbamoyl phosphate synthetase and anthranilate synthase. Typical GAT domains have Rossmann fold-like topology and possess a catalytic triad similar to that of proteases. The C-terminal domain of HPII catalase has the GAT Rossmann fold but lacks the triad and therefore loses enzymatic activity. In addition, we detect significant sequence similarity between thiJ domains, some of which are known to have protease activity, and typical GAT proteins. Evolutionary tree analysis of the entire GAT superfamily indicates that the HPII catalase is more closely related to thiJ domains than to classical GAT domains and is likely to have evolved from a thiJ-like protein. This work illustrates the strength of sequence-based profile analysis techniques coupled with structural superpositions in developing an evolutionarily relevant classification of protein structures.

Original languageEnglish (US)
Pages (from-to)230-236
Number of pages7
JournalProteins: Structure, Function and Genetics
Issue number2
StatePublished - Feb 1 2001


  • Fold assignment
  • Molecular evolution
  • Protein structure classification
  • Rossmann fold
  • ThiJ protease

ASJC Scopus subject areas

  • Structural Biology
  • Biochemistry
  • Molecular Biology


Dive into the research topics of 'The C-terminal domain of HPII catalase is a member of the type I glutamine amidotransferase superfamily'. Together they form a unique fingerprint.

Cite this