TY - JOUR
T1 - Structural basis for an inositol pyrophosphate kinase surmounting phosphate crowding
AU - Wang, Huanchen
AU - Falck, J R
AU - Hall, Traci M Tanaka
AU - Shears, Stephen B.
N1 - Funding Information:
Data were collected at the Southeast Regional Collaborative Access Team 22-ID/22-BM beamline at the Advanced Photon Source, Argonne National Laboratory. Supporting institutions may be found at http://www.ser-cat.org/members.html. The use of the Advanced Photon Source was supported by the US Department of Energy, Office of Science, Office of Basic Energy Sciences, under contract no. W-31-109-Eng-38. This work was supported by the Intramural Research Program of the National Institutes of Health and National Institute of Environmental Health Sciences (NIEHS). We are grateful to L.C. Pedersen for advice and support. We also thank H. Ke for his assistance in writing the manuscript. Expression vectors were prepared by the NIEHS Protein Expression Core Facility.
PY - 2012/1
Y1 - 2012/1
N2 - Inositol pyrophosphates (such as IP7 and IP8) are multifunctional signaling molecules that regulate diverse cellular activities. Inositol pyrophosphates have 'high-energy' phosphoanhydride bonds, so their enzymatic synthesis requires that a substantial energy barrier to the transition state be overcome. Additionally, inositol pyrophosphate kinases can show stringent ligand specificity, despite the need to accommodate the steric bulk and intense electronegativity of nature's most concentrated three-dimensional array of phosphate groups. Here we examine how these catalytic challenges are met by describing the structure and reaction cycle of an inositol pyrophosphate kinase at the atomic level. We obtained crystal structures of the kinase domain of human PPIP5K2 complexed with nucleotide cofactors and either substrates, product or a MgF 3 - transition-state mimic. We describe the enzyme's conformational dynamics, its unprecedented topological presentation of nucleotide and inositol phosphate, and the charge balance that facilitates partly associative in-line phosphoryl transfer.
AB - Inositol pyrophosphates (such as IP7 and IP8) are multifunctional signaling molecules that regulate diverse cellular activities. Inositol pyrophosphates have 'high-energy' phosphoanhydride bonds, so their enzymatic synthesis requires that a substantial energy barrier to the transition state be overcome. Additionally, inositol pyrophosphate kinases can show stringent ligand specificity, despite the need to accommodate the steric bulk and intense electronegativity of nature's most concentrated three-dimensional array of phosphate groups. Here we examine how these catalytic challenges are met by describing the structure and reaction cycle of an inositol pyrophosphate kinase at the atomic level. We obtained crystal structures of the kinase domain of human PPIP5K2 complexed with nucleotide cofactors and either substrates, product or a MgF 3 - transition-state mimic. We describe the enzyme's conformational dynamics, its unprecedented topological presentation of nucleotide and inositol phosphate, and the charge balance that facilitates partly associative in-line phosphoryl transfer.
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U2 - 10.1038/nchembio.733
DO - 10.1038/nchembio.733
M3 - Article
C2 - 22119861
AN - SCOPUS:83655198346
SN - 1552-4450
VL - 8
SP - 111
EP - 116
JO - Nature chemical biology
JF - Nature chemical biology
IS - 1
ER -