PolydA and polyrA self‐structured by a europium and amino acid complex

Zhang, Haiyuan; Yu, Haijia; Ren, Jinsong; Qu, Xiaogang

doi:10.1016/j.febslet.2006.05.046

Cited by 20 publications

(47 citation statements)

References 34 publications

(51 reference statements)

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“…2D) indicate that SWNTs could not only stabilize i-motif structure but also induce its formation at pH 8.0. The structural transition was cooperative (22)(23)(24)(25), with a midpoint at 5 g⅐ml…”

Section: Resultsmentioning

confidence: 99%

“…CD spectra and CD melting experiments were measured on a JASCO J-810 spectropolarimeter equipped with a temperaturecontrolled water bath (19,22,23,25). The optical chamber of CD spectrometer was deoxygenated with dry purified nitrogen (99.99%) for 45 min before use and kept the nitrogen atmosphere during experiments.…”

Section: Methodsmentioning

confidence: 99%

“…Concentrations of these oligomers were determined by measuring the absorbance at 260 nm after melting. Extinction coefficients were estimated by the nearest-neighbor method by using mononucleotide and dinucleotide values (9,12,23,25,32). All experiments were carried out in aqueous cacodylic buffer (33) (0.1 mM cacodylic acid/sodium cacodylate/100 mM NaCl) unless stated otherwise.…”

Section: Methodsmentioning

confidence: 99%

“…All UV/Vis spectra were measured in 1.0-cm-path-length cell with the same concentration of SWNT aqueous solution accordingly as the reference solution. Absorbance changes at either 260 nm or 295 nm vs. temperature were collected (19,23,25) at a heating rate of 0.5°C⅐min Ϫ1 . Primary data were transferred to the graphics program Origin for plotting and analysis.…”

Section: Methodsmentioning

confidence: 99%

“…1 H NMR spectra (25,34) were carried out on a Bruker Avance 600 MHz NMR Spectrometer at 10°C. Individual DNA samples were used at different pH conditions (26) in the absence or presence of SWNTs in 100 mM NaCl, 0.1 mM EDTA, and 0.01 mM DSS solution.…”

Section: Methodsmentioning

confidence: 99%

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Carboxyl-modified single-walled carbon nanotubes selectively induce human telomeric i-motif formation

Peng

Ren

et al. 2006

Proc. Natl. Acad. Sci. U.S.A.

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As the leading nanodevice candidate, single-walled carbon nanotubes (SWNTs) have potential therapeutic applications in gene therapy and novel drug delivery. We found that SWNTs can inhibit DNA duplex association and selectively induce human telomeric i-motif DNA formation by binding to the 5-end major groove under physiological conditions or even at pH 8.0. SWNT binding to telomeric DNA was studied by UV melting, NMR, S1 nuclease cleavage, CD, and competitive FRET methods. These results suggest that SWNTs might have the intriguing potential to modulate human telomeric DNA structures in vivo, like biologically relevant B-A and B-Z DNA transitions, which is of great interest for drug design and cancer therapy. Since the discovery of the DNA i-motif, the formation and biological function of this unique structure have attracted much attention, and significant progress in characterizing the i-motif has been made in recent years (1, 2). The biological importance of the intramolecular i-motif is evidenced by its involvement in human telomeric and centromeric DNA structures and RNA intercalated structures, and by the discovery of several proteins that bind specifically to C-rich telomeric DNA fragments capable of forming i-motifs (2). Along with human telomeric G-quadruplex DNA, the i-motif has been an attractive drug target for cancer chemotherapy and for modulation of gene transcription (2-9). Human telomeres consist of tandem repeats of the double-stranded DNA sequence (5Ј-TTAGGG):(5Ј-CCCTAA) (3-9). The G-rich strand can form a four-stranded G-quadruplex consisting of G-quartets, whereas its complementary C-rich strand may adopt i-motif structures with intercalated C⅐C ϩ base pairs ( Fig. 1). Significantly, G-quadruplex formation was shown to inhibit the activity of telomerase, an enzyme that stabilizes chromosome ends by adding tandem telomeric DNA repeats to the 3Ј single-stranded overhangs (4,5,10). In contrast to the majority of normal human somatic cells, most tumor cells express telomerase, and telomerase expression is essential for their indefinite proliferative capacities. Therefore, the therapeutic targeting of telomerase activity has been considered a promising approach to cancer therapy (4, 5, 10). Several small molecules have been shown to efficiently inhibit telomerase activity through the stabilization of G-quadruplex DNA (4, 5). Only two molecules that can stabilize both G-quadruplex and i-motif DNA have been identified (11,12). To our knowledge, a ligand that can selectively stabilize i-motif DNA but not G-quadruplex DNA has not been reported.As the leading nanodevice candidate, single-walled carbon nanotubes (SWNTs) have potential applications ranging from gene therapy to novel drug delivery to membrane separation (13-17). B-Z DNA transition has been achieved on the surfaces of SWNTs (18). Recently we reported that SWNTs bind to the DNA major groove and can induce a sequence-dependent B-A DNA transition (19). In the present study we show that SWNTs can selectively stabilize human telomeric i-motif DN...

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Section: Resultsmentioning

confidence: 99%

Section: Methodsmentioning

confidence: 99%

Section: Methodsmentioning

confidence: 99%

Section: Methodsmentioning

confidence: 99%

Section: Methodsmentioning

confidence: 99%

See 3 more Smart Citations

Carboxyl-modified single-walled carbon nanotubes selectively induce human telomeric i-motif formation

Peng

Ren

et al. 2006

Proc. Natl. Acad. Sci. U.S.A.

Self Cite

246

294

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Nucleoside Triphosphates as Promoters to Enhance Nanoceria Enzyme‐like Activity and for Single‐Nucleotide Polymorphism Typing

Liu

et al. 2013

Adv Funct Materials

112

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Nucleoside triphosphates (NTPs) can improve the oxidase‐like activity of nanoceria and the enhancement is correlated with the type of NTP. This effect is demonstrated to be as a result of the coupling of the oxidative reaction with the NTP hydrolysis reactions, as the nanoceria has both oxidase‐like and phosphatase‐like activities. The differences reflect the different dephosphorylation catalytic activities of nanoceria to the NTP used. Furthermore, based on the NTP‐promoted oxidase‐like activity of nanoceria and the differences among the different types of NTPs, series effective and high‐throughput colorimetric assays for single‐nucleotide polymorphism (SNP) typing are developed.

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Self‐Assembly of Single‐Stranded RNA on Carbon Nanotube: Polyadenylic Acid to Form a Duplex Structure

Zhao

Peng

Song

et al. 2008

Small

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All messenger-RNA (mRNA) molecules in eukaryotic cells have a polyadenylic acid [poly(rA)] tail at the 3'-end and human poly(rA) polymerase (PAP) has been considered as a tumor-specific target. A ligand that is capable of recognizing and binding to the poly(rA) tail of mRNA might interfere with the full processing of mRNA by PAP and can be a potential therapeutic agent. We report here for the first time that single-walled carbon nanotubes (SWNTs) can cause single-stranded poly(rA) to self-structure and form a duplex structure, which is studied by UV melting, atomic force microscopy, circular dichroism spectroscopy, and NMR spectrometry. SWNTs have shown potential applications that range from nanodevices, gene therapy, and drug delivery to membrane separations. Our studies may provide new insights into the application of SWNTs under physiological conditions, possibly being used as probes that target specific gene sequences.

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PolydA and polyrA self‐structured by a europium and amino acid complex

Cited by 20 publications

References 34 publications

Carboxyl-modified single-walled carbon nanotubes selectively induce human telomeric i-motif formation

Carboxyl-modified single-walled carbon nanotubes selectively induce human telomeric i-motif formation

Nucleoside Triphosphates as Promoters to Enhance Nanoceria Enzyme‐like Activity and for Single‐Nucleotide Polymorphism Typing

Self‐Assembly of Single‐Stranded RNA on Carbon Nanotube: Polyadenylic Acid to Form a Duplex Structure

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