Each year, the Berkeley Lab Director’s Achievement Award program recognizes outstanding contributions by employees to all facets of Lab activities. Several Biosciences Area personnel are among the 2022 honorees.
The protein CheY plays a role in relaying sensory signals from chemoreceptors to the rotary motor at the base of the tail-like appendage, or flagellum, that protrudes from the cell body of certain bacteria and eukaryotic cells. It has been studied as a model for dissecting the mechanism of allostery—the process by which the binding of biological macromolecules (mainly proteins) at one location regulates activity at another, often distant, functional site. When it is transiently phosphorylated in response to chemotactic cues, CheY’s binding affinity for a flagellar motor switch protein called FliM is enhanced. CheY binding to FliM changes the direction of flagellar rotation from counterclockwise to clockwise.
Using X-ray footprinting with mass spectroscopy (XFMS), a team led by Shahid Khan, a senior scientist with the Molecular Biology Consortium, established that CheY changes shape when it tethers to the motor, and further parsed the contribution of phosphorylation to this shape change. The results of the XFMS experiments validated atomistic molecular dynamics (MD) predictions of the architecture of the allosteric communication network, marking the first time that XFMS has been used to validate protein dynamics simulations at single-residue resolution sampled over the complete protein.
A team of Berkeley Lab researchers conducted X-ray footprinting mass spectrometry (XFMS) experiments at the Lab’s Advanced Light Source (ALS) to pinpoint how a protein of the bacterium Shewanella oneidensis transfers electrons to a metal oxide substrate. The research was led by Caroline Ajo-Franklin, whose lab is part of the Molecular Foundry and who holds a secondary appointment in the Molecular Biophysics and Integrated Bioimaging (MBIB) division, in collaboration with Corie Ralston, also of MBIB. Tatsuya Fukushima, a former postdoc in Ajo-Franklin’s lab, and Sayan Gupta, a member of Ralston’s lab, were co-first authors on the paper published in the Journal of the American Chemical Society. The study, which identified an unexpectedly small and weak binding site, also benefitted from expertise and tools contributed by Joint BioEnergy Institute (JBEI) and Biological Systems and Engineering (BSE) researchers Christopher Petzold and Leanne Jade Chan. Read more at the Berkeley Lab News Center.