The synthetase domains of cobalamin biosynthesis amidotransferases CobB and CobQ belong to a new family of ATP-dependent amidoligases, related to dethiobiotin synthetase

Michael Y. Galperin, Nick V. Grishin

Research output: Contribution to journalArticle

19 Scopus citations

Abstract

Phosphotransacetylases of Escherichia coli and several other bacteria contain an additional 350-aa N-terminal fragment that is not required for phosphotransacetylase activity. Sequence analysis of this fragment revealed that it is closely related to a family of ATP-dependent enzymes that also includes dethiobiotin synthetase and the synthetase domains of two amidotransferases involved in cobalamin biosynthesis, cobyrinic acid a,c-diamide synthase (CobB) and cobyric acid synthase (CobQ). Further database searches showed that this enzyme family is also related to the MinD family of ATPases involved in regulation of cell division in bacteria and archaea. Analysis of sequence conservation in the members of this enzyme family using the structure of dethiobiotin synthetase active site as a guide allowed us to suggest a model for the interaction of CobB and CobQ with their respective substrates. CobB and CobQ were also found to contain unusual Triad family (class I) glutamine amidotransferase domains with conserved Cys and His residues, but lacking the Glu residue of the catalytic triad. These results should help in understanding the enzymology of cobalamin biosynthesis and in resolving the role of phosphotransacetylase in regulation of the carbon flow to and from acetate.

Original languageEnglish (US)
Pages (from-to)238-247
Number of pages10
JournalProteins: Structure, Function and Genetics
Volume41
Issue number2
DOIs
StatePublished - Nov 1 2000

Keywords

  • Acetyl phosphate
  • Bacterial cell division
  • Domain structure
  • Enzyme family
  • Genome analysis
  • MinD protein
  • Vitamin B12 biosynthesis

ASJC Scopus subject areas

  • Structural Biology
  • Biochemistry
  • Molecular Biology

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