Recently, numerous biological macromolecular experiments have been conducted with optical tweezers. For the single molecular stretching experiment with optical tweezers, three ways to determine the initial adhesion po...Recently, numerous biological macromolecular experiments have been conducted with optical tweezers. For the single molecular stretching experiment with optical tweezers, three ways to determine the initial adhesion point of DNA on the coverslip are described in this work. In addition, a new method through analyzing the displacement variance of the trapped particle to obtain the trap height is introduced. Using our proposed methods, the obtained force-extension curve for the operated dsDNA agrees well with the worm-like chain model. These improved methods are also applicable to other related biological macromolecular experiments requiring high precision.展开更多
Deoxyribonucleic acid(DNA) carries the genetic information in all living organisms. It consists of two interwound single-stranded(ss) strands, forming a double-stranded(ds) DNA with a right-handed double-helical confo...Deoxyribonucleic acid(DNA) carries the genetic information in all living organisms. It consists of two interwound single-stranded(ss) strands, forming a double-stranded(ds) DNA with a right-handed double-helical conformation. The two strands are held together by highly specific basepairing interactions and are further stabilized by stacking between adjacent basepairs. A transition from a dsDNA to two separated ssDNA is called melting and the reverse transition is called hybridization. Applying a tensile force to a dsDNA can result in a particular type of DNA melting, during which one ssDNA strand is peeled away from the other. In this work, we studied the kinetics of strand-peeling and hybridization of short DNA under tensile forces. Our results show that the force-dependent strand-peeling and hybridization can be described with a simple two-state model. Importantly, detailed analysis of the force-dependent transition rates revealed that the transition state consists of several basepairs dsDNA.展开更多
基金Supported by the National Natural Science Foundation of China under Grant No 91023049the National Basic Research Program of China under Grant No 2012CB937500
文摘Recently, numerous biological macromolecular experiments have been conducted with optical tweezers. For the single molecular stretching experiment with optical tweezers, three ways to determine the initial adhesion point of DNA on the coverslip are described in this work. In addition, a new method through analyzing the displacement variance of the trapped particle to obtain the trap height is introduced. Using our proposed methods, the obtained force-extension curve for the operated dsDNA agrees well with the worm-like chain model. These improved methods are also applicable to other related biological macromolecular experiments requiring high precision.
基金supported by the Fundamental Research Funds for the Central Universities(Grant No.2013121005)the National Natural Science Foundation of China(Grant Nos.11474237 and 11574310)+1 种基金the 111 Project (Grant No.B16029)the National Research Foundation of Singapore through the NRF Investigatorship and the Mechanobiology Institute
文摘Deoxyribonucleic acid(DNA) carries the genetic information in all living organisms. It consists of two interwound single-stranded(ss) strands, forming a double-stranded(ds) DNA with a right-handed double-helical conformation. The two strands are held together by highly specific basepairing interactions and are further stabilized by stacking between adjacent basepairs. A transition from a dsDNA to two separated ssDNA is called melting and the reverse transition is called hybridization. Applying a tensile force to a dsDNA can result in a particular type of DNA melting, during which one ssDNA strand is peeled away from the other. In this work, we studied the kinetics of strand-peeling and hybridization of short DNA under tensile forces. Our results show that the force-dependent strand-peeling and hybridization can be described with a simple two-state model. Importantly, detailed analysis of the force-dependent transition rates revealed that the transition state consists of several basepairs dsDNA.
