Formation of an intramolecular G-quadruplex of human telomere induced by poly(L-lysine) under salt-deficient conditions.
A single-stranded G-tract human telomere DNA sequence is able to fold into intramolecular G-quadruplex structures which may be important for a number of biological processes and disease-related mechanisms. Poly(L-lysine) (PLL) polymer is linear polypeptides with lysine as the repeat unit and has been employed as a gene carrier in achieving targeted delivery of DNA to cancer cells. To explore the influence of PLL on the conformation of Hum24 DNA, we have investigated the interaction of PLL with Hum24 by biophysical methods, mainly CD, ESI-MS, and polyacrylamide gel electrophoresis for the first time. The CD data have shown that PLL can induce single-stranded Hum24 to form an intramolecular parallel G-quadruplex structure, further confirmed by ESI-MS analysis and gel electrophoresis results. The formation of an intramolecular G-quadruplex is strongly dependent on the Hum24/PLL molar ratios and the length of both the polypeptides and oligonucleotide. Such phenomena may be interpreted by electrostatically attracting negative-charged Hum24 by positive-charged PLL which facilitates the close contact between the guanines and formation of hydrogen bonding, thus leading the final shape of a G-quadruplex structure.
Zhang
Xiu-feng
XF
Beijing National Laboratory for Molecular Sciences, State Key Laboratory for Structural Chemistry of Unstable and Stable Species, Institute of Chemistry, Chinese Academy of Sciences, Beijing 100190, China.
Xiang
Jun-feng
JF
Tian
Ming-yue
MY
Yang
Qian-fan
QF
Sun
Hong-xia
HX
Yang
Shu
S
Tang
Ya-lin
YL
D002942:Circular Dichroism; D004277:DNA, Single-Stranded / Q000737:chemistry*; D004591:Electrophoresis, Polyacrylamide Gel; D054856:G-Quadruplexes; D006801:Humans; D009690:Nucleic Acid Conformation; D009838:Oligodeoxyribonucleotides / Q000737:chemistry; D011107:Polylysine / Q000737:chemistry*; D011188:Potassium / Q000737:chemistry*; D012964:Sodium / Q000737:chemistry*; D021241:Spectrometry, Mass, Electrospray Ionization; D016615:Telomere / Q000737:chemistry*
D004277:DNA, Single-Stranded; D009838:Oligodeoxyribonucleotides; D011107:Polylysine; D012964:Sodium; D011188:Potassium