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Shay Caspi

Publications and source records attributed to Shay Caspi.

3 recordsLinked to original sources

Conformation changes and folding of proteins mediated by Davidov's soliton

We suggest that Davidov's solitons, propagating through the backbone of a protein, can mediate conformational transition and folding of a protein to its native state. A simple toy model is presented in which a Non Linear Schrodinger (NLS) field interacts with another field phi, corresponding to the conformation angles of the protein. The interaction provides the conformation field with the energy needed in order to overcome energy barriers for folding, thus avoiding the need for stochastic thermal activation. Such a transition is therefore a deterministic controled process.The soliton is compensated for its energy loss by absorption of the energy gained in the folding process. This scenario does not change significantly even in the presence of imposed disorder, provided that the initial momentum of the soliton is large enough.

cond-mat

DNA - Nanoelectronics: Realization of a Single Electron Tunneling Transistor and a Quantum Bit Element

Based on the understanding that chemical bonds can act as tunnel junctions in the Coulomb blockade regime, and on the technical ability to coat a DNA strand with metal, we suggest that DNA can be used to built logical devices. We discuss two explicit examples: a Single Electron Tunneling Transistor (SET) and a Quantum Bit Element. These devices would be literally in the nano-meter scale and would be able to operate at room temperature. In addition they would be identical to each other, highly stable and would have a self assembly property.

physics.bio-ph

Do Topological Charge Solitons Participate in DNA Activity?

We present a novel electromagnetic model of DNA molecules, in which the P-bonds act as tunnel junctions and the H-bonds as capacitors. Excess charge in the model gives rise to two coupled modified sine-Gordon equations, which admit topological solitonic excitations. We study the dynamics of the solitons, their effect on the DNA transport properties, and comment about their role in the DNA functioning. We propose specific experiments in order to test our predictions.

physics.bio-ph