| Structural highlights
4aqk is a 1 chain structure with sequence from Arath. Full crystallographic information is available from OCA. For a guided tour on the structure components use FirstGlance.
| | Ligands: | , , , |
| Related: | 2xal, 2xam, 2xan, 2xao, 2xar |
| Activity: | Inositol-pentakisphosphate 2-kinase, with EC number 2.7.1.158 |
| Resources: | FirstGlance, OCA, PDBe, RCSB, PDBsum, ProSAT |
Function
[IPPK_ARATH] Phosphorylates Ins(1,3,4,5,6)P5 at position 2 to form Ins(1,2,3,4,5,6)P6 (InsP6 or phytate). Phytate is a regulator of intracellular signaling, a highly abundant animal antinutrient, and a phosphate store in plant seeds. Also phosphorylates Ins(1,3,4,6)P4 and Ins(1,4,5,6)P4 to produce Ins(1,2,3,4,6)P5 and Ins(1,2,4,5,6)P5.[1] [2]
Publication Abstract from PubMed
Inositol 1,3,4,5,6-pentakisphosphate 2-kinase (IP(5) 2-K) is a key enzyme that catalyzes the synthesis of phytic acid (IP(6)) from inositol 1,3,4,5,6-pentakisphosphate (IP(5)) and ATP. The first structure of IP(5) 2-K, that from Arabidopsis thaliana, has been solved previously; it only crystallized in the presence of inositol, either the substrate IP(5) or the product IP(6), and failed to crystallize in its free state (without inositol). Based on structural analysis, a point mutation of IP(5) 2-K (W129A) has been produced in order to overcome this limitation and obtain information about protein conformational changes upon substrate binding. Here, the production and crystallization of W129A IP(5) 2-K in its free state and with bound nucleotide is described. These crystals differed from the native crystals and belonged to the orthorhombic space group P2(1)2(1)2, with unit-cell parameters a = 66.00, b = 68.23, c = 105.80 A and a = 63.06, b = 71.80, c = 100.23 A, respectively. The crystals diffracted to resolutions of 2.22 A (apo) and 2.05 A (nucleotide bound) using synchrotron radiation and contained one molecule per asymmetric unit. The structures have been determined using the molecular-replacement method and refinement is being undertaken.
Expression, purification, crystallization and preliminary X-ray diffraction analysis of the apo form of InsP5 2-K from Arabidopsis thaliana.,Banos-Sanz JI, Sanz-Aparicio J, Brearley CA, Gonzalez B Acta Crystallogr Sect F Struct Biol Cryst Commun. 2012 Jun 1;68(Pt 6):701-4. doi:, 10.1107/S1744309112017307. Epub 2012 May 23. PMID:22684075[3]
From MEDLINE®/PubMed®, a database of the U.S. National Library of Medicine.
References
- ↑ Stevenson-Paulik J, Bastidas RJ, Chiou ST, Frye RA, York JD. Generation of phytate-free seeds in Arabidopsis through disruption of inositol polyphosphate kinases. Proc Natl Acad Sci U S A. 2005 Aug 30;102(35):12612-7. Epub 2005 Aug 17. PMID:16107538 doi:10.1073/pnas.0504172102
- ↑ Sweetman D, Johnson S, Caddick SE, Hanke DE, Brearley CA. Characterization of an Arabidopsis inositol 1,3,4,5,6-pentakisphosphate 2-kinase (AtIPK1). Biochem J. 2006 Feb 15;394(Pt 1):95-103. PMID:16223361 doi:BJ20051331
- ↑ Banos-Sanz JI, Sanz-Aparicio J, Brearley CA, Gonzalez B. Expression, purification, crystallization and preliminary X-ray diffraction analysis of the apo form of InsP5 2-K from Arabidopsis thaliana. Acta Crystallogr Sect F Struct Biol Cryst Commun. 2012 Jun 1;68(Pt 6):701-4. doi:, 10.1107/S1744309112017307. Epub 2012 May 23. PMID:22684075 doi:http://dx.doi.org/10.1107/S1744309112017307
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