5opn | pdb_00005opn
Crystal structure of R39Q cN-II mutant
Structural highlights
Disease[5NTC_HUMAN] Autosomal recessive spastic paraplegia type 45. The disease is caused by mutations affecting the gene represented in this entry.[1] Function[5NTC_HUMAN] May have a critical role in the maintenance of a constant composition of intracellular purine/pyrimidine nucleotides in cooperation with other nucleotidases. Preferentially hydrolyzes inosine 5'-monophosphate (IMP) and other purine nucleotides. Publication Abstract from PubMedActivating mutations in NT5C2, a gene encoding cytosolic purine 5'-nucleotidase (cN-II), confer chemoresistance in relapsed acute lymphoblastic leukemia. Here we show that all mutants became independent of allosteric effects of ATP and thus constitutively active. Structural mapping of mutations described in patients demonstrates that 90% of leukemia-specific allelles directly affect two regulatory hotspots within the cN-II molecule-the helix A region: residues 355-365, and the intersubunit interface: helix B (232-242) and flexible interhelical loop L (400-418). Furthermore, analysis of hetero-oligomeric complexes combining wild-type (WT) and mutant subunits showed that the activation is transmitted from the mutated to the WT subunit. This intersubunit interaction forms structural basis of hyperactive NT5C2 in drug-resistant leukemia in which heterozygous NT5C2 mutation gave rise to hetero-tetramer mutant and WT proteins. This enabled us to define criteria to aid the prediction of NT5C2 drug resistance mutations in leukemia. Relapsed acute lymphoblastic leukemia-specific mutations in NT5C2 cluster into hotspots driving intersubunit stimulation.,Hnizda A, Fabry M, Moriyama T, Pachl P, Kugler M, Brinsa V, Ascher DB, Carroll WL, Novak P, Zaliova M, Trka J, Rezacova P, Yang JJ, Veverka V Leukemia. 2018 Jun;32(6):1393-1403. doi: 10.1038/s41375-018-0073-5. Epub 2018 Feb, 25. PMID:29535428[2] From MEDLINE®/PubMed®, a database of the U.S. National Library of Medicine. References
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