Engineering Approaches to Biomolecular Motors

Engineering Approaches to Biomolecular Motors: From in vitro to in vivo Wednesday Speaker Abstracts

Molecular Machinery from DNA

Andrew J. Turberfield

University of Oxford, Oxford, United Kingdom.

By exploiting programmable, sequence-dependent base-pairing interactions it is possible to

design and build three-dimensional DNA scaffolds, to attach molecular components to them with

sub-nanometre precision – and then to make them move. I shall describe our work on

autonomous, biomimetic molecular motors powered by chemical fuels, hybrid DNA-kinesin

devices, motors that compute, and the use of synthetic molecular machinery to control covalent

chemical synthesis.

A Synthetic DNA Motor that Transports Nanoparticles along Carbon Nanotubes

Jing Pan,

Jong Hyun Choi

Purdue University, West Lafayette, IN, USA.

Intracellular protein motors have evolved to perform specific tasks critical to the function of cells

such as intracellular trafficking and cell division. Inspired by such biological machines, we

demonstrate that motors based on RNA-cleaving DNAzymes can transport nanoparticle cargoes

(CdS nanocrystals in this case) along single-walled carbon nanotubes. Our synthetic motors

extract chemical energy from interactions with RNA molecules decorated on the nanotubes and

use that energy to fuel autonomous, processive walking through a series of conformational

changes along the one-dimensional track. However, their translocation kinetics is not well

understood. In this work, the translocation kinetics of individual DNAzyme motors are probed in

real-time using the visible fluorescence of the cargo nanoparticle and the near-IR emission of the

carbon nanotube track. This visible/near-IR single-particle/single-tube spectroscopy allows us to

examine the critical parameters in the motor design that govern the translocation kinetics,

including DNA enzyme catalytic core type, upper and lower recognition arm lengths, and

various divalent metal cations. Combined with spectroscopic single-motor measurements, a

simple theoretical model, developed within the framework of stochastic single-molecule kinetics,

describes the rates of individual intermediate reactions as well as the overall single turnover

reaction. Our study provides general design guidelines to construct highly processive,

autonomous DNA walker systems and to regulate their translocation kinetics, which would

facilitate the development of functional DNA walkers.