In bacteria, what __drives__ the process of cell division is unknown. Possibly, forces generated by an internal protein ring (termed __the Z-ring__) are responsible for the division process, but... Show moreIn bacteria, what __drives__ the process of cell division is unknown. Possibly, forces generated by an internal protein ring (termed __the Z-ring__) are responsible for the division process, but direct evidence is lacking. Here we describe the development of a method to measure forces in a single dividing bacterium. Using optical tweezers, forces can be measured on optically trapped micron-sized beads. To attach such a bead to a living bacterium, one of its outer membrane proteins is engineered to present a binding epitope on the cell surface. We show that it is possible to attach a bead to this __molecular handle__ via a DNA-molecule, and characterize the strength of this molecular construct. Finally, we show that genetic fusion of the surface exposed protein domain to an internal domain with mid-cell affinity can alter the localization pattern of the exposed domain. Our findings suggest that it is possible to create a fusion protein that exposes a binding epitope and localizes specifically to the division site. Show less
