1t6c | pdb_00001t6c
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Structural characterization of the Ppx/GppA protein family: crystal structure of the Aquifex aeolicus family member
Overview
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.
About this Structure
1T6C is a Single protein structure of sequence from Aquifex aeolicus vf5 with IOD, CA, CL and MPD as ligands. Full crystallographic information is available from OCA.
Reference
Structural characterization of the stringent response related exopolyphosphatase/guanosine pentaphosphate phosphohydrolase protein family., Kristensen O, Laurberg M, Liljas A, Kastrup JS, Gajhede M, Biochemistry. 2004 Jul 20;43(28):8894-900. PMID:15248747
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