Filtering molecules with electrostatic interactions.
V - Biofisica e fisica medica
Aula 32C-2 - Martedì 18 h 09:00 - 13:00
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The transfer of information is fundamental for cell and microorganism functionalities. A way to communicate is based on transport of small molecules. Starting from some general bacterial pores used as model systems (OmpF and OmpC from E.coli), we identified the way in which molecules are selectively transferred in and out from bacteria. The two structural features controlling transport are (i) the hourglass shape of the pore, and (ii) a segregation of charges in the central region. The former property avoids the uncontrolled flux of molecules, creating an unselective barrier for penetration. The latter, on the other hand, can be very specific: by creating a transversal electric field, it allows molecules with a particular dipole moment to have high flux. This mechanism, an entropic general barrier compensated by specific electrostatic properties, has the advantage of avoiding saturation. Further, these structural features can be easily transferred in designing synthetic nanopores for selecting/sensing specific molecules.