Transition metal ions and selenite modulate the methylation of arsenite by the recombinant human arsenic (+3 oxidation state) methyltransferase (hAS3MT)

Song, Xiaoli; Geng, Zhirong; Li, Chengying; Hu, Xin; Wang, Zhilin

doi:10.1016/j.jinorgbio.2010.01.005

Cited by 15 publications

(9 citation statements)

References 65 publications

(84 reference statements)

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“…The intrinsic ultraviolet–visible (UV–vis) absorption peak of PML-R at 280 nm is primarily caused by Trp47, and the intensity of this peak can indicate perturbation of the microenvironment around Trp47. 17 , 31 After incubation with Se 4+ for 15 min, the intensity of the 280 nm peak was increased. Compared with Zn 2+ and As 3+ , Se 4+ increased the intensity at 280 nm more obviously ( Figure 8a ).…”

Section: Resultsmentioning

confidence: 95%

“…To determine the mechanism of Se 4+ binding, the effects of Se 4+ on thiol groups of PML-R were analyzed by the method of Ellman. 27 , 31 A total of 4.76 (thiol group/mol of protein) thiol groups were detected in PML-R ( Figure 8f ). Unlike Zn 2+ and As 3+ , Se 4+ dramatically eliminated the thiol groups in PML-R, indicating stronger coordination with Cys residues ( Figure 8f ).…”

Section: Resultsmentioning

confidence: 99%

“…UV–vis spectra of PML-R were recorded on a Perkin Elmer Lambda-35 spectrophotometer (Waltham, MA, USA). 31 CD spectra were measured by a JASCO-J810 spectropolarimeter (Jasco Co., Tokyo, Japan). 27 The molar ratio of metal ion to PML-R was 2 : 1.…”

Section: Methodsmentioning

confidence: 99%

“…The effects of Zn 2+ , As 3+ , and Se 4+ on free thiol groups in PML-R were determined by the method of Ellman. 27 , 31 The reaction mixtures (200 μ l) containing 20 μ M PML-R and ion (Zn 2+ , As 3+ , or Se 4+ ) were incubated at 37 °C for 2 h. The molar ratios of ion to PML-R were 0 : 1, 1 : 1, 2 : 1, and 4 : 1. After reaction, PML-R was incubated with 0.1 μ M 5,5′-dithiobis-(2-nitrobenzoic acid) (DTNB) in Tris-HCl buffer (20 mM, pH 8.0) at 25 °C for 30 min.…”

Section: Methodsmentioning

confidence: 99%

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Dose-dependent effects of selenite (Se4+) on arsenite (As3+)-induced apoptosis and differentiation in acute promyelocytic leukemia cells

et al. 2015

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To enhance the therapeutic effects and decrease the adverse effects of arsenic on the treatment of acute promyelocytic leukemia, we investigated the co-effects of selenite (Se4+) and arsenite (As3+) on the apoptosis and differentiation of NB4 cells and primary APL cells. A 1.0-μM concentration of Se4+ prevented the cells from undergoing As3+-induced apoptosis by inhibiting As3+ uptake, eliminating As3+-generated reactive oxygen species, and repressing the mitochondria-mediated intrinsic apoptosis pathway. However, 4.0 μM Se4+ exerted synergistic effects with As3+ on cell apoptosis by promoting As3+ uptake, downregulating nuclear factor-кB, and activating caspase-3. In addition to apoptosis, 1.0 and 3.2 μM Se4+ showed contrasting effects on As3+-induced differentiation in NB4 cells and primary APL cells. The 3.2 μM Se4+ enhanced As3+-induced differentiation by promoting the degradation of promyelocytic leukemia protein–retinoic acid receptor-α (PML–RARα) oncoprotein, but 1.0 μM Se4+ did not have this effect. Based on mechanistic studies, Se4+, which is similar to As3+, might bind directly to Zn2+-binding sites of the PML RING domain, thus controlling the fate of PML–RARα oncoprotein.

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Section: Resultsmentioning

confidence: 95%

Section: Resultsmentioning

confidence: 99%

Section: Methodsmentioning

confidence: 99%

Section: Methodsmentioning

confidence: 99%

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Dose-dependent effects of selenite (Se4+) on arsenite (As3+)-induced apoptosis and differentiation in acute promyelocytic leukemia cells

et al. 2015

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“…Attenuated total reflection Fourier transform infrared (ATR-FTIR) spectra were also used to analyze the secondary structure of the mutants. More details about the ATR-FTIR spectra are given in previous works [18]–[20], [34]–[36].…”

Section: Methodsmentioning

confidence: 99%

Identification of the Third Binding Site of Arsenic in Human Arsenic (III) Methyltransferase

Geng

Chang

et al. 2013

PLoS ONE

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Arsenic (III) methyltransferase (AS3MT) catalyzes the process of arsenic methylation. Each arsenite (iAs3+) binds to three cysteine residues, methylarsenite (MMA3+) binds to two, and dimethylarsenite (DMA3+) binds to one. However, only two As-binding sites (Cys156 and Cys206) have been confirmed on human AS3MT (hAS3MT). The third As-binding site is still undefined. Residue Cys72 in Cyanidioschyzon merolae arsenite S-adenosylmethyltransferase (CmArsM) may be the third As-binding site. The corresponding residue in hAS3MT is Cys61. Functions of Cys32, Cys61, and Cys85 in hAS3MT are unclear though Cys32, Cys61, and Cys85 in rat AS3MT have no effect on the enzyme activity. This is why the functions of Cys32, Cys61, and Cys85 in hAS3MT merit investigation. Here, three mutants were designed, C32S, C61S, and C85S. Their catalytic activities and conformations were determined, and the catalytic capacities of C156S and C206S were studied. Unlike C85S, mutants C32S and C61S were completely inactive in the methylation of iAs3+ and active in the methylation of MMA3+. The catalytic activity of C85S was also less pronounced than that of WT-hAS3MT. All these findings suggest that Cys32 and Cys61 markedly influence the catalytic activity of hAS3MT. Cys32 and Cys61 are necessary to the first step of methylation but not to the second. Cys156 and Cys206 are required for both the first and second steps of methylation. The SC32 is located far from arsenic in the WT-hAS3MT-SAM-As model. The distances between SC61 and arsenic in WT-hAS3MT-As and WT-hAS3MT-SAM-As models are 7.5 Å and 4.1 Å, respectively. This indicates that SAM-binding to hAS3MT shortens the distance between SC61 and arsenic and promotes As-binding to hAS3MT. This is consistent with the fact that SAM is the first substrate to bind to hAS3MT and iAs is the second. Model of WT-hAS3MT-SAM-As and the experimental results indicate that Cys61 is the third As-binding site.

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Selenium Interactions with Other Trace Elements, with Nutrients (and Drugs) in Humans

Arnaud

Dael

2018

Molecular and Integrative Toxicology

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Transition metal ions and selenite modulate the methylation of arsenite by the recombinant human arsenic (+3 oxidation state) methyltransferase (hAS3MT)

Cited by 15 publications

References 65 publications

Dose-dependent effects of selenite (Se4+) on arsenite (As3+)-induced apoptosis and differentiation in acute promyelocytic leukemia cells

Dose-dependent effects of selenite (Se4+) on arsenite (As3+)-induced apoptosis and differentiation in acute promyelocytic leukemia cells

Identification of the Third Binding Site of Arsenic in Human Arsenic (III) Methyltransferase

Selenium Interactions with Other Trace Elements, with Nutrients (and Drugs) in Humans

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