Séminaire IPCM | Jan C. Behrends "Probing the shape of macromolecules with ions: from polymer sizing to sequencing"

L'IPCM invites you to a seminar presented by

the Professor Jan C. Behrends (University of Freiburg Germany)

Title
"Probing the shape of macromolecules with ions: from polymer sizing to sequencing"

When a macromolecule enters a narrow ion-conducting path through an insulator, such as a protein pore of channel in a membrane or a nanoscopic aperture in a crystalline substrate, any current driven by a voltage through this path is reduced. The sensitivity of the residual current to the nature of the “blocker” is such that when e.g. single stranded DNA is driven through a pore in a linear, controlled fashion, so that few monomers determine the residual conductivity, the resulting  current pattern can be used to deduce the sequence of nucleotides. Alternatively, by stochastically entrapping an entire macromolecule in a pore, the residual current -now determined by all monomers- can be used to discriminate between different sizes and even shapes with surprising sensitivity. A method will be shown to use this principle to discriminate between positional isomers of peptides resulting from posttranslational modification of human histone proteins. In addition, an approach will be introduced to use whole molecule nanopore trapping for peptide sequence recognition by sequential cleavage of peptide bonds, opening an avenue towards direct protein sequencing by nanopore.