کد مقاله کد نشریه سال انتشار مقاله انگلیسی نسخه تمام متن
1938467 1050740 2007 6 صفحه PDF دانلود رایگان
عنوان انگلیسی مقاله ISI
RecA-ssDNA filaments supercoil in the presence of single-stranded DNA-binding protein
موضوعات مرتبط
علوم زیستی و بیوفناوری بیوشیمی، ژنتیک و زیست شناسی مولکولی زیست شیمی
پیش نمایش صفحه اول مقاله
RecA-ssDNA filaments supercoil in the presence of single-stranded DNA-binding protein
چکیده انگلیسی

Using atomic force microscopy (AFM), we find that RecA-single-stranded DNA (RecA-ssDNA) filaments, in the presence of single-stranded DNA-binding (SSB) protein, organize into left-handed bundles, which differ from the previously reported disordered aggregates formed when SSB is excluded from the reaction. In addition, we see both left- and right-handedness on bundles of two filaments. These two-filament supercoils, individual filaments, and other smaller bundles further organize into more complicated bundles, showing overall left-handedness which cannot be explained by earlier arguments that presumed supercoiling is absent in RecA-ssDNA filaments. This novel finding and our previous results regarding supercoiling of RecA-double-stranded DNA (RecA-dsDNA) filaments are, however, consistent with each other and can possibly be explained by the intrinsic tendency of RecA-DNA filaments, in their fully coated form, to order themselves into helical bundles, independent of the DNA inside the filaments (ssDNA or dsDNA). RecA–RecA interactions may dominate the bundling process, while the original conformation of DNA inside filaments and other factors (mechanical properties of filaments, concentration of filaments, and Mg2+ concentration) could contribute to the variation in the appearance and pitch of supercoils. The tendency of RecA-DNA filaments to form ordered supercoils and their presence during strand exchange suggest a possible biological importance of supercoiled filaments.

ناشر
Database: Elsevier - ScienceDirect (ساینس دایرکت)
Journal: Biochemical and Biophysical Research Communications - Volume 357, Issue 3, 8 June 2007, Pages 755–760
نویسندگان
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