High Speed AFM reveals membrane transporter dynamics

Researchers from Groningen and Japan have recorded real-time movies of the nanoscale movements of transporter proteins. These proteins are found in the membrane of cells and have as task to specifically transport certain molecules into or out of the cell. Due to their minute size, researchers typically can only indirectly study transporter dynamics. With the recently developed High Speed-Atomic Force Microscopy (HS-AFM) it is now possible to follow in real-time the movements of these nanometer sized, nature-made machines. The results are published in Proceedings of the National Academy of Sciences USA.

The studied molecular transporter shuttles citrate across the cytoplasmic membrane of bacteria and crystal structures suggested an elevator type of transport mechanism with two states. However, up-to-date no dynamic measurements had been performed to validate or falsify this. Using HS-AFM the dynamic up-and-down movement of these tiny machines was confirmed, but unexpectedly instead of two, three states were discovered. These states only differed ~0.5 nm in height. This successful collaboration between the labs of prof. dr. Dirk Slotboom of the GBB and prof. dr. Wouter Roos of ZIAM was brought to the next level after the travels of first author dr. Sourav Maity to Japan. Here the technical approach was perfected and the collaboration with the Japanese colleagues turned out very fruitful.

Reference
Sourav Maity, Gianluca Trinco, Pedro Buzón, Zaid R. Anshari, Noriyuki Kodera, Kien Xuan Ngo, Toshio Ando, Dirk J. Slotboom, Wouter H. Roos* High Speed-Atomic Force Microscopy reveals a three state elevator-mechanism in the citrate transporter CitS Proc. Natl. Acad. Sci. U. S. A., 2022, 119 (6), e2113927119

Contact
Contact details of Prof. dr. Wouter Roos can be found on his homepage: https://www.rug.nl/research/zernike/molecular-biophysics/roos-group/