Nanopore-based determination of protein charge, shape, volume, rotational diffusion coefficient, and dipole moment

摘要

Physical parameters of macromolecules are determined by measuring electrical current I over time for translocation events as the macromolecules in solution move between two liquid compartments that are separated by and fluidically coupled through a synthetic nanopore. Values of charge, volume, shape, rotational diffusion coefficient, ad dipole moment are derived from the measurements.

主权项

1. A method of deriving values for physical parameters of a particle, comprising:
(a) measuring electrical current I or equivalent electrical parameter as a function of time between two liquid compartments separated by and fluidically coupled through a synthetic nanopore upon translocation of the particle and a plurality of other particles in a plurality of translocation events from one liquid compartment through the synthetic nanopore to the other liquid compartment; (b) detecting translocation events by recognizing a change in current ΔI relative to a baseline current; (c) collecting values of intra-event values ΔI(t); (d) for the plurality of translocation events, finding a value ΔImax of a maximum change in current and a value ΔImin of a minimum change in current; (e) deriving a volume Λ of the particle and a length to diameter ratio m of the particle from the distribution of values of ΔImax from the translocation events; and (f) deriving one or more of a rotational diffusion coefficient DR and a dipole moment μ of the particle from the volume Λ of the particle, the length to diameter ratio m of the particle, and the intra-event values ΔI(t).