2XAO

Inositol 1,3,4,5,6-pentakisphosphate 2-kinase from A. thaliana in complex with IP5

Summary for 2XAO

• Entry DOI: 10.2210/pdb2xao/pdb
• Related: 2XAL 2XAM 2XAN 2XAR
• Descriptor: INOSITOL-PENTAKISPHOSPHATE 2-KINASE, MYO-INOSITOL-(1,3,4,5,6)-PENTAKISPHOSPHATE, ZINC ION (3 entities in total)
• Functional Keywords: transferase, inositol polyphosphate kinase, phytic acid synthase
• Biological source: Arabidopsis thaliana (THALE CRESS)
• Total number of polymer chains: 2
• Total formula weight: 102726.10

Authors

Gonzalez, B.,Banos-Sanz, J.I.,Villate, M.,Brearley, C.A.,Sanz-Aparicio, J. (deposition date: 2010-03-31, release date: 2010-05-19, Last modification date: 2023-12-20)

Primary citation

Gonzalez, B.,Banos-Sanz, J.I.,Villate, M.,Brearley, C.A.,Sanz-Aparicio, J.
Inositol 1,3,4,5,6-Pentakisphosphate 2-Kinase is a Distant Ipk Member with a Singular Inositide Binding Site for Axial 2-Oh Recognition.
Proc.Natl.Acad.Sci.USA, 107:9608-, 2010

PubMed Abstract: Inositol phosphates (InsPs) are signaling molecules with multiple roles in cells. In particular (InsP(6)) is involved in mRNA export and editing or chromatin remodeling among other events. InsP(6) accumulates as mixed salts (phytate) in storage tissues of plants and plays a key role in their physiology. Human diets that are exclusively grain-based provide an excess of InsP(6) that, through chelation of metal ions, may have a detrimental effect on human health. Ins(1,3,4,5,6)P(5) 2-kinase (InsP(5) 2-kinase or Ipk1) catalyses the synthesis of InsP(6) from InsP(5) and ATP, and is the only enzyme that transfers a phosphate group to the axial 2-OH of the myo-inositide. We present the first structure for an InsP(5) 2-kinase in complex with both substrates and products. This enzyme presents a singular structural region for inositide binding that encompasses almost half of the protein. The key residues in substrate binding are identified, with Asp368 being responsible for recognition of the axial 2-OH. This study sheds light on the unique molecular mechanism for the synthesis of the precursor of inositol pyrophosphates.

PubMed: 20453199
DOI: 10.1073/PNAS.0912979107

Experimental method

X-RAY DIFFRACTION (2.9 Å)