| AVS 60th International Symposium and Exhibition | |
| Biomolecules at Aqueous Interfaces Focus Topic | Monday Sessions |
| Session BA+AI+AS+BI+IS+NL-MoM |
| Session: | Biomolecules at Aqueous Interfaces |
| Presenter: | K.B. Eisenthal, Columbia University |
| Authors: | K.B. Eisenthal, Columbia University B. Doughty, Columbia University Y. Rao, Columbia University S.M. Kazer, Columbia University S.J.J. Kwok, Columbia University N.T. Turro, Columbia University |
| Correspondent: | Click to Email |
The work reported here utilizes a sensitive method for the investigation of biomolecular interactions that has the important characteristic of not requiring chemical labels, e.g. fluorophores, nor invasive detection methods. The surface selective second order spectroscopies, second harmonic, SHG, and sum frequency generation, SFG, allow one to probe equilibrium properties and time dependent changes in the electronic and vibrational structure of molecules located at interfaces. In addition they have the special feature of being able to monitor changes in the electrical charge of the interacting molecules. 1) A new way is presented to measure the binding constants of molecules, e.g. drugs and proteins, with DNA tethered to colloidal microparticles suspended in aqueous solution. 2) Time resolved second harmonic generation was used to observe the binding of an enzyme to its recognition site on DNA, followed by the cleaving of DNA into a small and a large fragment, and the subsequent DNA rehybridization dynamics. 3) The relative orientation of two molecules bound to DNA is manipulated by changing the number of nucleotide base pairs separating them. The interference between the SH electric fields generated by the pair of molecules is modulated because their relative orientation changes as the number of nucleotide base pairs separating them is changed. With this method we have a new way to probe structural changes in DNA due to the binding of biomolecules to it.