Development of state-of-the-art single molecule force-spectroscopy techniques
The laboratory is typically populated by an eclectic mixture of molecular biologists, physiologists, and physicists. We develop all the protein engineering, software and instrumentation necessary for our measurements. The most recent development is the application of Magnetic Tweezers (MT) to pull from single polyproteins. This is the result of a collaboration with the group of Jie Yan at the Mechanbiology Institute (Singapore). Using MT, we have been able to examine a single protein for over 15 hours, and we believe this is only the beginning! For the first time, we have resolved collapse trajectories from single protein domains, which we are now actively investigating. These advancements have been made possible thanks to the HaloTag technology, which allows to covalently attach single proteins a glass surface. We are developing a second covalent anchoring technology that will enable end-to-end covalent tethering.
The focus of the lab has been for many years AFM. We have distilled over 15 years of experience in AFM to produce a simple automatic force-clamp spectrometer that can accurately set the pulling force with a sub-millisecond time constant and very low drift and can be left running automatically for long periods of time. Direct readout of single protein lengths has an effortless resolution of 1 nm. With digital filtering it reaches 0.1 nm. The new machine is ideal to probe the conformational dynamics of single proteins. This spectrometer is now being manufactured by the company Luigs and Neumann of Rattingen/Germany. In November 2013, Luigs and Neumann shipped one of the new AFMs to an experimental workshop in Stellenbosch (South Africa) where students were able to obtain state-of-the-art single-molecule recordings.
Disclosure: Columbia University has licensed intellectual property to Luigs and Neumann Gmbh. In accordance with University policy, Dr. Fernandez is entitled to royalties through this license.
Our next goal is to build a force spectrometer with high-throughput capabilities, to be able to screen for molecules that alter mechanical properties of proteins. This technological advancement is the first step towards Mechano-Pharmacology, a new way of finding drugs that could be used to treat cardiac disease or fight against bacterial infections.