title: Structural insights into the inhibition of cytosolic 5'-nucleotidase II (cN-II) by ribonucleoside 5'-monophosphate analogues.
abstract: Cytosolic 5'-nucleotidase II (cN-II) regulates the intracellular nucleotide pools within the cell by catalyzing the dephosphorylation of 6-hydroxypurine nucleoside 5'-monophosphates. Beside this physiological function, high level of cN-II expression is correlated with abnormal patient outcome when treated with cytotoxic nucleoside analogues. To identify its specific role in the resistance phenomenon observed during cancer therapy, we screened a particular class of chemical compounds, namely ribonucleoside phosphonates to predict them as potential cN-II inhibitors. These compounds incorporate a chemically and enzymatically stable phosphorus-carbon linkage instead of a regular phosphoester bond. Amongst them, six compounds were predicted as better ligands than the natural substrate of cN-II, inosine 5'-monophosphate (IMP). The study of purine and pyrimidine containing analogues and the introduction of chemical modifications within the phosphonate chain has allowed us to define general rules governing the theoretical affinity of such ligands. The binding strength of these compounds was scrutinized in silico and explained by an impressive number of van der Waals contacts, highlighting the decisive role of three cN-II residues that are Phe 157, His 209 and Tyr 210. Docking predictions were confirmed by experimental measurements of the nucleotidase activity in the presence of the three best available phosphonate analogues. These compounds were shown to induce a total inhibition of the cN-II activity at 2 mM. Altogether, this study emphasizes the importance of the non-hydrolysable phosphonate bond in the design of new competitive cN-II inhibitors and the crucial hydrophobic stacking promoted by three protein residues.
authors.affiliation: Institut des Biomolécules Max Mousseron, UMR 5247, CNRS - Universités Montpellier 1 et 2, Université Montpellier 2, Montpellier, France.
authors.forename: Franck
authors.initials: F
authors.lastname: Gallier
authors.forename: Perrine
authors.initials: P
authors.lastname: Lallemand
authors.forename: Maïa
authors.initials: M
authors.lastname: Meurillon
authors.forename: Lars P
authors.initials: LP
authors.lastname: Jordheim
authors.forename: Charles
authors.initials: C
authors.lastname: Dumontet
authors.forename: Christian
authors.initials: C
authors.lastname: Périgaud
authors.forename: Corinne
authors.initials: C
authors.lastname: Lionne
authors.forename: Suzanne
authors.initials: S
authors.lastname: Peyrottes
authors.forename: Laurent
authors.initials: L
authors.lastname: Chaloin
mesh_terms: D015720:5'-Nucleotidase / Q000037:antagonists & inhibitors* / Q000737:chemistry* / Q000378:metabolism; D001665:Binding Sites; D006868:Hydrolysis; D007291:Inosine Monophosphate / Q000737:chemistry / Q000378:metabolism; D008958:Models, Molecular; D012265:Ribonucleotides / Q000737:chemistry* / Q000378:metabolism; D013329:Structure-Activity Relationship; D013379:Substrate Specificity
chemical_list: D012265:Ribonucleotides; D007291:Inosine Monophosphate; D015720:5'-Nucleotidase