The crystal structure of Escherichia coli purine nucleoside phosphorylase: a comparison with the human enzyme reveals a conserved topology

Chen, Mao; Cook, William J.; Zhou, Min; Koszalka, George W.; Krenitsky, Thomas A.; Ealick, S.E.

doi:10.1016/s0969-2126(97)00287-6

Cited by 135 publications

(129 citation statements)

References 33 publications

(41 reference statements)

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“…Because E. coli PNP assembles as a hexamer, transactivation might be less than with luciferase, which is active as a monomer. 10,11 Nevertheless, transactivation of E. coli PNP using this approach was also substantial. E. coli PNP expression at 24 h after transfection with the tat constructs was 947 + 76 conversion units (n = 13) versus no conversion in luciferase-transfected controls.…”

Section: Resultsmentioning

confidence: 96%

In vivo sensitization of ovarian tumors to chemotherapy by expression of E. coli purine nucleoside phosphorylase in a small fraction of cells

et al. 2000

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Section: Resultsmentioning

confidence: 96%

In vivo sensitization of ovarian tumors to chemotherapy by expression of E. coli purine nucleoside phosphorylase in a small fraction of cells

et al. 2000

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“…The PfPNP sequence has greater similarity to E. coli than to human PNP (9), and its structure is hexameric as is the E. coli enzyme (7,20,21). PfPNP, however, has unique substrate specificity when compared with either E. coli or mammalian PNPs (9,21).…”

Section: Resultsmentioning

confidence: 99%

“…We overexpressed and tested E. coli PNP, which has been extensively characterized structurally and enzymatically (20,21). E. coli PNP has activity against inosine and adenosine but has no detectable activity toward MTA or MTI.…”

Section: Resultsmentioning

confidence: 99%

Targeting a Novel Plasmodium falciparum Purine Recycling Pathway with Specific Immucillins

Ting¹,

Shi

Lewandowicz

et al. 2005

Journal of Biological Chemistry

111

182

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Plasmodium falciparum is unable to synthesize purine bases and relies upon purine salvage and purine recycling to meet its purine needs. We report that purines formed as products of polyamine synthesis are recycled in a novel pathway in which 5 -methylthioinosine is generated by adenosine deaminase. The action of P. falciparum purine nucleoside phosphorylase is a convergent step of purine salvage, converting both 5 -methylthioinosine and inosine to hypoxanthine. We used accelerator mass spectrometry to verify that 5 -methylthioinosine is an active nucleic acid precursor in P. falciparum. Prior studies have shown that inhibitors of purine salvage enzymes kill malaria, but potent malaria-specific inhibitors of these enzymes have not been described previously. 5 -Methylthio-immucillin-H, a transition state analogue inhibitor that is selective for malarial relative to human purine nucleoside phosphorylase, kills P. falciparum in culture. Immucillins are currently in clinical trials for other indications and may also have application as anti-malarials.

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“…Such differences in specificity between the hexameric and trimeric PNPs are in agreem ent with different architectures of the active centres and differences in specific interactions between the purine bases and the enzyme, observed in the crystal structures of E. coli. calf spleen and human erythrocyte phosphorylases (Mao et al, 1997(Mao et al, , 1998Koellner et al, 1997Koellner et al, , 1998Narayana et al, 1997).…”

Section: Introductionmentioning

confidence: 99%

Synthesis of 6-Aryloxy- and 6-Arylalkoxy-2-chloropurines and Their Interactions with Purine Nucleoside Phosphorylase from Escherichia coli

Bzowska

Magnowska

Kazimierczuk³

1999

Zeitschrift Für Naturforschung C

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The phase transfer method was applied to perform the nucleophilic substitution of 2,6-dichloropurines by modified arylalkyl alcohol or phenols. Since under these conditions only the 6-halogen is exchanged, this method gives 2-chloro-6-aryloxy-and 2-chloro-6-arylalkoxypurines. 2-Chloro-6-benzylthiopurine was synthesized by alkylation of 2-chloro-6-thiopurine with benzyl bromide. The stereoisom ers of 2-chloro-6-(l-phenyl-l-ethoxy)purine were ob tained from R-and 5-enantiomers of sec.-phenylethylalcohol and 2,6-dichloropurine.A ll derivatives were tested for inhibition with purified hexameric E. coli purine nucleoside phosphorylase (PNP). For analogues showing IC50 < 10 ^.m, the type o f inhibition and inhibi tion constants were determined. In all cases the experimental data were best described by the mixed-type inhibition model and the uncompetitive inhibition constant, Kiu, was found to be several-fold lower than the competitive inhibition constant, Kic. This effect seems to be due to the 6-aryloxy-or 6-arylalkoxy substituent, because a natural PNP substrate adenine, as well as 2-chloroadenine, show mixed type inhibition with almost the same inhibition con stants Kiu and K1C . = 0.4, 0.6, 1.4, 1.4 and 2.2 [im, respectively). The i?-stereoisomer o f 2-chloro-6-(lpheny-l-ethoxy)purine has Kiu = 2.0 ^im, whereas inhibition o f its S counterpart is rather weak (IC50> 12 jim). More rigid (e.g. phenoxy-), non-planar (cyclohexyloxy-), or more bulky (2,4,6-trimethylphenoxy-) substituents at position 6 of the purine base gave less potent inhibi tors (IC50 = 26, 56 and >100 [im, respectively). The derivatives are selective inhibitors of hexameric "high-molecular mass" PNPs because no inhibitory activity vs. trimeric Cellulomonas sp. PNP was detected. The most potent inhibition was observed for 6-benzylthio-2-chloro-, 6-benzyloxy-2-chloro-, 2-chloro-6-(2-phenyl-l-ethoxy), 2-chloro-6-(3-phenyl-l-propoxy)-and 2-chloro-6-ethoxypurines (KiuBy establishing the ligand-dependent stabilization pattern of the E. coli PNP it was shown that the new derivatives, similarly as the natural purine bases, are able to form a dead-end ternary complex with the enzyme and orthophosphate. It was also shown that the derivatives are substrates in the reverse synthetic direction catalyzed by E. coli PNP

show abstract

The crystal structure of Escherichia coli purine nucleoside phosphorylase: a comparison with the human enzyme reveals a conserved topology

Cited by 135 publications

References 33 publications

In vivo sensitization of ovarian tumors to chemotherapy by expression of E. coli purine nucleoside phosphorylase in a small fraction of cells

In vivo sensitization of ovarian tumors to chemotherapy by expression of E. coli purine nucleoside phosphorylase in a small fraction of cells

Targeting a Novel Plasmodium falciparum Purine Recycling Pathway with Specific Immucillins

Synthesis of 6-Aryloxy- and 6-Arylalkoxy-2-chloropurines and Their Interactions with Purine Nucleoside Phosphorylase from Escherichia coli

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