4lqy

Crystal Structure of Human ENPP4 with AMP

spinqualitylabelsall models 4lqy, resolution 1.54Å Show:Asymmetric Unit Biological Assembly Drag the structure with the mouse to rotate   Export Animated Image   Print3D Structural highlights 4lqy is a 1 chain structure with sequence from Homo sapiens. Full crystallographic information is available from OCA. For a guided tour on the structure components use FirstGlance. Method: X-ray diffraction, Resolution 1.54Å Ligands: AMP, NAG, ZN Resources: FirstGlance, OCA, PDBe, RCSB, PDBsum, ProSAT Function ENPP4_HUMAN Hydrolyzes extracellular Ap3A into AMP and ADP, and Ap4A into AMP and ATP. Ap3A and Ap4A are diadenosine polyphosphates thought to induce proliferation of vascular smooth muscle cells. Acts as a procoagulant, mediating platelet aggregation at the site of nascent thrombus via release of ADP from Ap3A and activation of ADP receptors. Publication Abstract from PubMed NPP4 is a type I extracellular membrane protein on brain vascular endothelium inducing platelet aggregation via the hydrolysis of Ap3A, whereas NPP1 is a type II extracellular membrane protein principally present on the surface of chondrocytes that regulates tissue mineralization. To understand the metabolism of purinergic signals resulting in the physiologic activities of the two enzymes, we report the high resolution crystal structure of human NPP4 and explore the molecular basis of its substrate specificity with NPP1. Both enzymes cleave Ap3A, but only NPP1 can hydrolyze ATP. Comparative structural analysis reveals a tripartite lysine claw in NPP1 that stabilizes the terminal phosphate of ATP, whereas the corresponding region of NPP4 contains features that hinder this binding orientation, thereby inhibiting ATP hydrolysis. Furthermore, we show that NPP1 is unable to induce platelet aggregation at physiologic concentrations reported in human blood, but it could stimulate platelet aggregation if localized at low nanomolar concentrations on vascular endothelium. The combined studies expand our understanding of NPP1 and NPP4 substrate specificity and range and provide a rational mechanism by which polymorphisms in NPP1 confer stroke resistance. Molecular basis of purinergic signal metabolism by ectonucleotide pyrophosphatase/phosphodiesterases 4 and 1 and implications in stroke.,Albright RA, Ornstein DL, Cao W, Chang WC, Robert D, Tehan M, Hoyer D, Liu L, Stabach P, Yang G, De La Cruz EM, Braddock DT J Biol Chem. 2014 Feb 7;289(6):3294-306. doi: 10.1074/jbc.M113.505867. Epub 2013 , Dec 12. PMID:24338010 From MEDLINE®/PubMed®, a database of the U.S. National Library of Medicine. See Also Ectonucleotide pyrophosphatase/phosphodiesterase 3D structures

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