Interaction of long telomeric DNAs with macrocyclic hexaoxazole as a G-quadruplex ligand

MedChemComm ◽  
2013 ◽  
Vol 4 (1) ◽  
pp. 260-264 ◽  
Author(s):  
Keisuke Iida ◽  
Gen Tsubouchi ◽  
Takahiro Nakamura ◽  
Satoki Majima ◽  
Hiroyuki Seimiya ◽  
...  
Keyword(s):  
Circular Dichroism ◽  
Living Cells ◽  
Dna Melting ◽  
Mobility Shift ◽  
Electrophoresis Mobility Shift Assay ◽  
G Quadruplex ◽  
Mobility Shift Assay ◽  
Circular Dichroïsm

The interactions of long telomeric DNAs, which mimic telomeres in living cells, with a macrocyclic hexaoxazole ligand L2H2-6OTD (2) were investigated by means of electrophoresis mobility shift assay, circular dichroism (CD) titration analysis, and DNA melting measurements.

scholarly journals Nucleolin stabilizes G-quadruplex structures folded by the LTR promoter and silences HIV-1 viral transcription

2015 ◽  
Vol 43 (18) ◽  
pp. 8884-8897 ◽  
Author(s):  
Elena Tosoni ◽  
Ilaria Frasson ◽  
Matteo Scalabrin ◽  
Rosalba Perrone ◽  
Elena Butovskaya ◽  
...  
Keyword(s):  
Transcriptional Activity ◽  
Cellular Protein ◽  
Spectrometric Analysis ◽  
Viral Transcription ◽  
Mobility Shift ◽  
Binding Preference ◽  
G Quadruplex ◽  
Mobility Shift Assay ◽  
Ltr Promoter ◽  
Hiv 1

Abstract Folding of the LTR promoter into dynamic G-quadruplex conformations has been shown to suppress its transcriptional activity in HIV-1. Here we sought to identify the proteins that control the folding of this region of proviral genome by inducing/stabilizing G-quadruplex structures. The implementation of electrophorethic mobility shift assay and pull-down experiments coupled with mass spectrometric analysis revealed that the cellular protein nucleolin is able to specifically recognize G-quadruplex structures present in the LTR promoter. Nucleolin recognized with high affinity and specificity the majority, but not all the possible G-quadruplexes folded by this sequence. In addition, it displayed greater binding preference towards DNA than RNA G-quadruplexes, thus indicating two levels of selectivity based on the sequence and nature of the target. The interaction translated into stabilization of the LTR G-quadruplexes and increased promoter silencing activity; in contrast, disruption of nucleolin binding in cells by both siRNAs and a nucleolin binding aptamer greatly increased LTR promoter activity. These data indicate that nucleolin possesses a specific and regulated activity toward the HIV-1 LTR promoter, which is mediated by G-quadruplexes. These observations provide new essential insights into viral transcription and a possible low mutagenic target for antiretroviral therapy.

scholarly journals Interaction between Chromosomal Protein HMGB1 and DNA Studied by DNA-Melting Analysis

2014 ◽  
Vol 2014 ◽  
pp. 1-5 ◽  
Author(s):  
Elena V. Chikhirzhina ◽  
Starkova J. Tatiana ◽  
Alexander M. Polyanichko
Keyword(s):  
Circular Dichroism ◽  
Thermal Denaturation ◽  
Circular Dichroism Spectroscopy ◽  
Dna Melting ◽  
Chromosomal Protein ◽  
Melting Temperatures ◽  
Melting Analysis ◽  
Circular Dichroïsm ◽  
Nonhistone Chromosomal Protein ◽  
Biphasic Process

Interaction of HMGB1 nonhistone chromosomal protein with DNA was studied using circular dichroism spectroscopy and thermal denaturation of DNA. Melting DNA in the complex was shown to be a biphasic process. The characteristic melting temperatures of unbound DNA and the DNA bound to HMGB1 in 0.25 mM EDTA solutions were found to beTmI=44.0±0.5°C andTmII=62.0±1°C, respectively. It was shown that the binding of the HMGB1 molecule affects the melting of the DNA region approximately 30 b.p. long.

Irradiation with a diode at 820 nm induces changes in circular dichroism spectra (250-780 nm) of living cells

2001 ◽  
Vol 7 (6) ◽  
pp. 976-981 ◽  
Author(s):  
T.I. Karu ◽  
S.F. Kolyakov ◽  
L.V. Pyatibrat ◽  
E.L. Mikhailov ◽  
O.N. Kompanets
Keyword(s):  
Circular Dichroism ◽  
Living Cells ◽  
Circular Dichroism Spectra ◽  
Circular Dichroïsm
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