کد مقاله کد نشریه سال انتشار مقاله انگلیسی نسخه تمام متن
5371439 1503952 2011 7 صفحه PDF دانلود رایگان
عنوان انگلیسی مقاله ISI
HIV-integrase aptamer folds into a parallel quadruplex: A thermodynamic study
موضوعات مرتبط
مهندسی و علوم پایه شیمی شیمی تئوریک و عملی
پیش نمایش صفحه اول مقاله
HIV-integrase aptamer folds into a parallel quadruplex: A thermodynamic study
چکیده انگلیسی

Short guanine-rich sequences have a tendency to form quadruplexes that are stabilized by G-quartets with specific cation coordination. Quadruplexes are part of telomeres at the ends of chromosomes and play an important role in the regulation of gene expression. In addition, there is a strong interest in the therapeutic and biotechnological potential of quadruplex oligonucleotides. The HIV-integrase aptamer, d(GGGT)4, demonstrated unusually favorable van't Hoff thermodynamics, and based on NMR studies the aptamer was proposed to fold into an antiparallel structure. Here we probed an apparent discrepancy between the NMR structure and the quadruplex topology suggested by circular dichroism (CD). Systematic thermodynamic analyses of d(GGGT)4 and variants containing sequence modifications or missing specific nucleotides are consistent with a parallel quadruplex fold. CD studies carried out over a wide concentration range did not support a possible structural transition upon increasing strand concentration. Taken together, both optical and thermodynamic studies performed here strongly support a parallel fold for the d(GGGT)4 aptamer.

Graphical AbstractResearch highlights► Our thermodynamic study of d(GGGT)4 is consistent with a parallel quadruplex topology. ► CD studies carried out over a wide concentration range showed that the quadruplex maintains a parallel fold. ► In the presence of 10 mM KCl, the d(GGGT)4 quadruplex has a Tm of 90 °C. > Removal of the terminal 3'-T further stabilizes the structure. ► An ITC study of K+ interaction with (GGGT)3GGG suggests a two-step binding model.

ناشر
Database: Elsevier - ScienceDirect (ساینس دایرکت)
Journal: Biophysical Chemistry - Volume 155, Issues 2–3, May 2011, Pages 82-88
نویسندگان
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