Proteins consisting of identical subunits arranged symmetrically around a central axis (cyclic homo-oligomers) play key roles in many biological processes. Researchers have now developed a systematic approach to their design and demonstrated its accuracy using protein crystallography and small-angle x-ray scattering. Read more »
Science Briefs
Bacterial Symbiont Sequesters Arsenic and Barium in Sponges
Researchers used x-ray fluorescence, spectroscopy, and diffraction to study how populations of symbiotic bacteria can act as a detox organ in a host with no organs. The bacteria, members of the species Entotheonella, accumulate and mineralize large quantities of arsenic and barium in sponges. Read more »
A Closer Look at a Working Platinum/Electrolyte Interface
Ambient-pressure studies of the interface between a platinum electrode and an alkaline electrolyte revealed the molecular-level chemistry, structure, and dynamics of the platinum surface as a function of applied potential, highlighting differences between thermodynamic predictions and the actual surface composition. Read more »
A Hollow Pyramid Unlocks Principles of Protein Architecture
Researchers have designed a hollow, pyramid-shaped protein with a controllable cavity size that could be useful in the capture and release of smaller compounds. The tools and techniques developed could be useful in analyzing and optimizing designed protein assemblies and understanding their behavior in solution. Read more »
New Insights into Nanoscale Deformation
A group of scientists used Laue x-ray microdiffraction at the ALS to probe plastic deformation mechanisms at the nanoscale. Their findings may overturn conventional theory and reshape our understanding of the mechanical behavior of a host of nanocrystalline metals. Read more »
3D Visualization of Leaves during Drought
The veins of living leaves at increasing levels of drought stress were visualized using x-ray microtomography. The results expand our view of leaf drought responses, beyond the traditional embolism-centric view, to a broader focus on the role of the surrounding living tissues in water movement during drought. Read more »
Ancient Ocean Temperatures Recorded in Mother-of-Pearl
Researchers have shown that the thickness of the nacre, or mother-of-pearl, that lines the insides of mollusk shells can be used to estimate ocean temperatures as far back as the early Jurassic period. X-ray studies of modern and ancient shells help establish the method’s feasibility. Read more »
NCAA Drives Formation of Designed Proteins
A noncanonical amino-acid (NCAA) complex has been found to drive the self-assembly of a computationally designed protein. Bpy-ala, which is “noncanonical” because it’s not among the 20 amino acids that occur naturally, has useful properties that could be used to generate novel photoactive proteins. Read more »
Ptychography of a Bacterium’s Inner Compass
Magnetotactic bacteria (MTB) synthesize chains of magnetic nanocrystals (magnetosomes) that interact with the Earth’s magnetic field like an inner compass needle, simplifying their search for optimum environments. Ptychographic spectra of magnetosomes from a marine MTB provides insight into how these inner compasses form. Read more »
For Better Batteries, Open the Voltage Window
Electrochemical (battery) cells with aqueous electrolytes can be safe, inexpensive, and environmentally friendly, but they are limited by a narrow voltage window. X-ray absorption spectroscopy helps explain why an aqueous Na-ion system with Mn5O8 electrodes has a large voltage window and performs comparably to Li-ion batteries. Read more »
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