Tuyển tập báo cáo các nghiên cứu khoa học quốc tế ngành hóa học dành cho các bạn yêu hóa học tham khảo đề tài: Stretching and immobilization of DNA for studies of protein–DNA interactions at the single-molecule level | Nanoscale Res Lett 2007 2 185-201 DOI S11671-007-9057-5 NANO REVIEW Stretching and immobilization of DNA for studies of protein-DNA interactions at the single-molecule level Ji Hoon Kim Venkat Ram Dukkipati Stella W. Pang Ronald G. Larson Received 13 March 2007 Accepted 30 March 2007 Published online 18 April 2007 to the authors 2007 Abstract Single-molecule studies of the interactions of DNA and proteins are important in a variety of biological or biotechnology processes ranging from the protein s search for its DNA target site DNA replication transcription or repair and genome sequencing. A critical requirement for single-molecule studies is the stretching and immobilization of otherwise randomly coiled DNA molecules. Several methods for doing so have been developed over the last two decades including the use of forces derived from light magnetic and electric fields and hydrodynamic flow. Here we review the immobilization and stretching mechanisms for several of these techniques along with examples of single-molecule DNA-protein interaction assays that can be performed with each of them. Keywords DNA Single-molecule Proteins DNA-protein interactions Introduction DNA is a semi-flexible polymer composed of deoxyribonucleotide triphosphates dNTPs that are joined together by phosphodiester bonds. Common examples include bacteriophage DNA molecules such as k and T7 which J. H. Kim and V. R. Dukkipati contributed equally to this work. J. H. Kim R. G. Larson El Department of Chemical Engineering University of Michigan Ann Arbor 48109 MI USA e-mail rlarson@ V. R. Dukkipati S. W. Pang Department of Electrical Engineering and Computer Science University of Michigan Ann Arbor 48109 MI USA have been extensively used as templates for studying DNA-protein interactions 1-4 . The radius of gyration Rg of a self-avoiding polymer such as a coiled DNA quantifies its physical size in solution and can be expressed as r2 1 2 pd 1 5L3 5 where p is the persistence .
