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 language | English (US) |
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Pages (from-to) | 1021-1031 |
Number of pages | 11 |
Journal | Acta Crystallographica Section D: Biological Crystallography |
Volume | 65 |
Issue number | 10 |
DOIs | |
State | Published - 2009 |
Keywords
- Adenylylsulfate kinases
- APS kinases
- ATP sulfurylases
- Nucleotide kinase
- Sulfate metabolism
- Thiobacillus denitrificans
ASJC Scopus subject areas
- Structural Biology