Structure of the two-domain hexameric APS kinase from Thiobacillus denitrificans: Structural basis for the absence of ATP sulfurylase activity

Sean C. Gay, Irwin H. Segel, Andrew J Fisher

Research output: Contribution to journalArticle

9 Scopus citations

Abstract

The Tbd-0210 gene of the chemolithotrophic bacterium Thiobacillus denitrificans is annotated to encode a 60.5 kDa bifunctional enzyme with ATP sulfurylase and APS kinase activity. This putative bifunctional enzyme was cloned, expressed and structurally characterized. The 2.95 Å resolution X-ray crystal structure reported here revealed a hexa-meric assembly with D 3 symmetry. Each subunit contains a large N-terminal sulfurylase-like domain and a C-terminal APS kinase domain reminiscent of the two-domain fungal ATP sulfurylases of Penicillium chrysogenum and Saccharo-myces cerevisiae, which also exhibit a hexameric assembly. However, the T. denitrificans enzyme exhibits numerous structural and sequence differences in the N-terminal domain that render it inactive with respect to ATP sulfurylase activity. Surprisingly, the C-terminal domain does indeed display APS kinase activity, indicating that this gene product is a true APS kinase. Therefore, these results provide the first structural insights into a unique hexameric APS kinase that contains a nonfunctional ATP sulfurylase-like domain of unknown function.

Original languageEnglish (US)
Pages (from-to)1021-1031
Number of pages11
JournalActa Crystallographica Section D: Biological Crystallography
Volume65
Issue number10
DOIs
StatePublished - 2009

Keywords

  • Adenylylsulfate kinases
  • APS kinases
  • ATP sulfurylases
  • Nucleotide kinase
  • Sulfate metabolism
  • Thiobacillus denitrificans

ASJC Scopus subject areas

  • Structural Biology

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