کد مقاله کد نشریه سال انتشار مقاله انگلیسی نسخه تمام متن
1954905 1057806 2008 8 صفحه PDF دانلود رایگان
عنوان انگلیسی مقاله ISI
DNA Overstretching in the Presence of Glyoxal: Structural Evidence of Force-Induced DNA Melting
موضوعات مرتبط
علوم زیستی و بیوفناوری بیوشیمی، ژنتیک و زیست شناسی مولکولی زیست شیمی
پیش نمایش صفحه اول مقاله
DNA Overstretching in the Presence of Glyoxal: Structural Evidence of Force-Induced DNA Melting
چکیده انگلیسی

When a long DNA molecule is stretched beyond its B-form contour length, a transition occurs in which its length increases by a factor of 1.7, with very little force increase. A quantitative model was proposed to describe this transition as force-induced melting, where double-stranded DNA is converted into single-stranded DNA. The force-induced melting model accurately describes the thermodynamics of DNA overstretching as a function of solution conditions and in the presence of DNA binding ligands. An alternative explanation suggests a transformation into S-DNA, a double-stranded form which preserves the interstrand base pairing. To determine the extent to which DNA base pairs are exposed to solution during the transition, we held DNA overstretched to different lengths within the transition in the presence of glyoxal. If overstretching involved strand separation, then force-melted basepairs would be glyoxal-modified, thus essentially permanently single-stranded. Subsequent stretches confirm that a significant fraction of the DNA melted by force is permanently melted. This result demonstrates that DNA overstretching is accompanied by a disruption of the DNA helical structure, including a loss of hydrogen bonding.

ناشر
Database: Elsevier - ScienceDirect (ساینس دایرکت)
Journal: - Volume 95, Issue 3, 1 August 2008, Pages 1248–1255
نویسندگان
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