Structural characterization of the stringent response related exopolyphosphatase/guanosine pentaphosphate phosphohydrolase protein family

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Ole Kristensen, Martin Laurberg, Anders Liljas, Jette Sandholm Jensen Kastrup, Michael Gajhede

Exopolyphosphatase/guanosine pentaphosphate phosphohydrolase (PPX/GPPA) enzymes play central roles in the bacterial stringent response induced by starvation. The high-resolution crystal structure of the putative Aquifex aeolicus PPX/GPPA phosphatase from the actin-like ATPase domain superfamily has been determined, providing the first insights to features of the common catalytic core of the PPX/GPPA family. The protein has a two-domain structure with an active site located in the interdomain cleft. Two crystal forms were investigated (type I and II) at resolutions of 1.53 and 2.15 A, respectively. This revealed a structural flexibility that has previously been described as a "butterfly-like" cleft opening around the active site in other actin-like superfamily proteins. A calcium ion is observed at the center of this region in type I crystals, substantiating that PPX/GPPA enzymes use metal ions for catalysis. Structural analysis suggests that nucleotides bind at a similar position to that seen in other members of the superfamily.
Original languageEnglish
JournalBiochemistry
Volume43
Issue number28
Pages (from-to)8894-900
Number of pages7
ISSN0006-2960
DOIs
Publication statusPublished - 2004

    Research areas

  • Acid Anhydride Hydrolases, Adaptation, Physiological, Bacteria, Bacterial Proteins, Binding Sites, Calcium, Chlorine, Crystallization, Crystallography, X-Ray, Models, Molecular, Molecular Structure, Pyrophosphatases

ID: 40318589