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Geobacter nanowire structure surprise.
F Wang, Y Gu, JP O'Brien, SM Yi, SE Yalcin, V Srikanth, C Shen, D Vu, NL Ing, AI Hochbaum, EH Egelman, NS Malvankar. Cell 2019 doi: 10.1016/j.cell.2019.03.029 Bacteria living in anaerobic environments (no oxygen) need alternative electron acceptors in order to get energy from their food. An acceptor abundant in the earth's crust is red iron oxide ("rust"), which gets reduced to black iron oxide (magnetite). Many bacteria, such as Geobacter, get their metabolic energy by transferring electrons to acceptors that are multiple cell diameters distant, using protein nanowires. These were long thought to be pili. But when the structure of the nanowires was solved in 2019, to everyone's surprise, they turned out to be unprecedented linear polymers of multi-heme cytochromes. The hemes form an electrically conductive chain in the cores of these nanowires.
by Alice Clark (PDBe)
In the 1970s, an exciting discovery of a family of medicines was made by the Japanese scientist Satoshi Ōmura. One of these molecules, ivermectin, is shown in this artwork bound in the ligand binding pocket of the Farnesoid X receptor, a protein which helps regulate cholesterol in humans. This structure showed that ivermectin induced transcriptional activity of FXR and could be used to regulate metabolism.
ST Huber, D Terwiel, WH Evers, D Maresca, AJ Jakobi. Preprint 2022 doi: 10.1101/2022.05.08.489936 Many kinds of bacteria and archaea control their buoyancy to move to optimal positions in liquid environments. They do this by making nano-compartments called "gas vesicles", long "pipes" with closed ends filled with gases. In 2022, gas vesicle structure was solved, revealing self-assembling thin-walled cylinders of remarkable strength with gas-permeable pores and water-repelling (hydrophobic) interiors. Building on this structural knowledge, gas vesicles are being engineered to serve as biosensors that report via ultrasound.
The Capsid of a virus is its outer shell or "skin". Viruses have evolved intricate and elegant ways to assemble
capsid protein chains into complete, usually spherical capsids, often with icosahedral symmetry. Pictured is an extremely simplified model of a capsid, where a single enlarged atom represents each of the 360 protein chains in the capsid of the Simian Virus 40 (SV40), a member of a group of cancer-causing viruses that has been extensively researched for decades.