Engineering Approaches to Biomolecular Motors

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

Tools for Control and Observation of Synthetic Molecular Motors using Micro- and Nanofluidics Cassandra S. Niman 1 , Martin J. Zuckermann 2 , Martina Balaz 3,4 , Andrew Hudson 5 , Kara Van Aelst 6 , Jason P. Beech 3,4 , Jonas O. Tegenfeldt 3,4 , Paul M G. Curmi 7,8 , Dek N. Woolfson 6,9 , Mark Dillingham 6 , Nancy R. Forde 2 , Heiner Linke 3,4 . 1 University of California, San Diego, La Jolla, CA, USA, 2 Simon Fraser University, Burnaby, BC, Canada, 3 Lund University, Lund, Sweden, 4 Lund University, Lund, Sweden, 5 University of Leicester, Leicester, United Kingdom, 6 University of Bristol, Bristol, United Kingdom, 7 University of New South Wales, Sydney, New South Wales, Australia, 8 St. Vincent’s Hospital, Darlinghurst, New South Wales, Australia, 9 University of Bristol, Bristol, United Kingdom. This project aims to develop synthetic motors based on proteins and protein-DNA interactions. Specifically, we have developed two approaches to synthetic molecular motors that each isolate certain mechanisms for stepping observed in natural motors [1,2], namely rectification of diffusion and a power stroke. For both designs, the processivity of the motor is critically dependent on the coordination of feet-to-track binding. To this end, we induce coordinated binding between repressor proteins and DNA via changes of the ligands in solution surrounding the motors. We have fabricated and tested micro- and nanofluidic devices allowing for precise control over solute changes in the channels and simultaneous observation of motor movement via standard microscopy techniques [2,3]. These devices are designed either to minimize external forces due to fluid flow, or to enable testing of the motors’ performance against a load force. With a natural helicase motor, we have used a similar experimental scheme to demonstrate control of the motor motion via addition and withdrawal of the fuel supply, ATP, in the surrounding solution. Using total internal reflection fluorescence microscopy, we have monitored single helicase motors as they move and halt along DNA tracks. The micro- and nanofluidics, in combination with single molecule detection, set the stage for future measurements of synthetic molecular motors. These fluidic devices have a number of other potential applications, as they enable the chemical environment surrounding single molecules to be changed whilst causing minimal disturbance to these.

[1] Bromley et al. 2009, HFSP Journal, 3:204. [2] Niman et al. 2014, Nanoscale, 6(24):15008. [3] Niman et al. 2013, LabChip, 13:2389.

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