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

doi:10.1073/pnas.0607245103

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

Division of Biological Inorganic Chemistry, Key Laboratory of Rare Earth Chemistry and Physics, Graduate School of the Chinese Academy of Sciences, and Changchun Institute of Applied Chemistry, Chinese Academy of Sciences, Changchun, Jilin 130022, China

Edited by Donald M. Crothers, Yale University, New Haven, CT, and approved October 26, 2006 (received for review August 21, 2006)

Abstract

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.

Footnotes

*To whom correspondence should be addressed. E-mail: xqu{at}ciac.jl.cn
Author contributions: X.L. and Y.P. contributed equally to this work; J.R. and X.Q. designed research; X.L. and Y.P. performed research; X.L. and Y.P. analyzed data; and J.R. and X.Q. wrote the paper.
The authors declare no conflict of interest.
This article is a PNAS direct submission.
This article contains supporting information online at http://www.pnas.org/cgi/content/full/0607245103/DC1.
Abbreviations:

SWNT,

single-walled carbon nanotube;

2-Ap,

2-aminopurine;

TAMRA,

3′-tetramethylrhodamine.