|1yry, resolution 2.80Å ()|
Crystal structure of human PNP complexed with MESG
Purine nucleoside phosphorylase (PNP) catalyzes the reversible phosphorolysis of nucleosides and deoxynucleosides, generating ribose 1-phosphate and the purine base, which is an important step of purine catabolism pathway. The lack of such an activity in humans, owing to a genetic disorder, causes T-cell impairment, and drugs that inhibit this enzyme may have the potential of being utilized as modulators of the immunological system to treat leukemia, autoimmune diseases, and rejection in organ transplantation. Here, we describe kinetics and crystal structure of human PNP in complex with 7-methyl-6-thio-guanosine, a synthetic substrate, which is largely used in activity assays. Analysis of the structure identifies different protein conformational changes upon ligand binding, and comparison of kinetic and structural data permits an understanding of the effects of atomic substitution on key positions of the synthetic substrate and their consequences to enzyme binding and catalysis. Such knowledge may be helpful in designing new PNP inhibitors.
Kinetics and crystal structure of human purine nucleoside phosphorylase in complex with 7-methyl-6-thio-guanosine., Silva RG, Pereira JH, Canduri F, de Azevedo WF Jr, Basso LA, Santos DS, Arch Biochem Biophys. 2005 Oct 1;442(1):49-58. PMID:16154528
From MEDLINE®/PubMed®, a database of the U.S. National Library of Medicine.
[PNPH_HUMAN] Defects in PNP are the cause of purine nucleoside phosphorylase deficiency (PNPD) [MIM:613179]. It leads to a severe T-cell immunodeficiency with neurologic disorder in children.
[PNPH_HUMAN] The purine nucleoside phosphorylases catalyze the phosphorolytic breakdown of the N-glycosidic bond in the beta-(deoxy)ribonucleoside molecules, with the formation of the corresponding free purine bases and pentose-1-phosphate.
About this Structure
- Silva RG, Pereira JH, Canduri F, de Azevedo WF Jr, Basso LA, Santos DS. Kinetics and crystal structure of human purine nucleoside phosphorylase in complex with 7-methyl-6-thio-guanosine. Arch Biochem Biophys. 2005 Oct 1;442(1):49-58. PMID:16154528 doi:10.1016/j.abb.2005.07.021
- de Azevedo WF Jr, Canduri F, dos Santos DM, Silva RG, de Oliveira JS, de Carvalho LP, Basso LA, Mendes MA, Palma MS, Santos DS. Crystal structure of human purine nucleoside phosphorylase at 2.3A resolution. Biochem Biophys Res Commun. 2003 Aug 29;308(3):545-52. PMID:12914785
- ↑ Williams SR, Gekeler V, McIvor RS, Martin DW Jr. A human purine nucleoside phosphorylase deficiency caused by a single base change. J Biol Chem. 1987 Feb 15;262(5):2332-8. PMID:3029074
- ↑ Aust MR, Andrews LG, Barrett MJ, Norby-Slycord CJ, Markert ML. Molecular analysis of mutations in a patient with purine nucleoside phosphorylase deficiency. Am J Hum Genet. 1992 Oct;51(4):763-72. PMID:1384322
- ↑ Pannicke U, Tuchschmid P, Friedrich W, Bartram CR, Schwarz K. Two novel missense and frameshift mutations in exons 5 and 6 of the purine nucleoside phosphorylase (PNP) gene in a severe combined immunodeficiency (SCID) patient. Hum Genet. 1996 Dec;98(6):706-9. PMID:8931706
- ↑ Ealick SE, Rule SA, Carter DC, Greenhough TJ, Babu YS, Cook WJ, Habash J, Helliwell JR, Stoeckler JD, Parks RE Jr, et al.. Three-dimensional structure of human erythrocytic purine nucleoside phosphorylase at 3.2 A resolution. J Biol Chem. 1990 Jan 25;265(3):1812-20. PMID:2104852