Synopsis: Twist or twirl

Depending on their width, certain ribbon-forming biomolecules assume either twisted or spiral shapes.
Synopsis figure
Credit: Courtesy of L. Ziserman et al.

Many biomolecules such as nucleic acids, proteins, and lipids exhibit chirality that depends on how the molecules form, or self-assemble, into different shapes.

As their name suggests, chiral amphiphiles are molecules that are found in both aqueous and fatty environments. They self-assemble into myriad shapes, ranging from dotlike micelles to tubular micelles to two-dimensional sheets.

In a paper in Physical Review Letters, Lior Ziserman at the Technion-Israel Institute of Technology and colleagues, also in Israel, study a class of ribbon-forming chiral amphiphiles. With their cryogenic transmission electron microscopy imaging the authors capture a dynamic transition along a single ribbon that changes shape from twisted (negative Gaussian curvature) to spiral (zero Gaussian curvature). Quantitative analysis shows that the width of the ribbon determines the nature of this morphology. While the result is not unexpected—Monte Carlo simulations in 2004 predicted how curvature in certain molecules would depend on their physical properties, and subsequent analytic theory has predicted that change would behave as a phase transition—this is a useful experimental confirmation of a morphological change determined by ribbon width in such pervasive biological structures. – Sami Mitra


Features

More Features »

Announcements

More Announcements »

Subject Areas

Biological Physics

Previous Synopsis

Next Synopsis

Atomic and Molecular Physics

New place to search for Efimov states

Read More »

Related Articles

Synopsis: Jiggles that Help Bat Biosonar
Biological Physics

Synopsis: Jiggles that Help Bat Biosonar

The directional sensitivity of bat biosonar is improved by the wiggling of structures on the bat’s nose and ears. Read More »

Synopsis: Racing Bacteria
Biological Physics

Synopsis: Racing Bacteria

Bacteria track fast-moving chemical signals by hopping from one chemically favorable region to another. Read More »

Synopsis: Cell Sensing Improves in a Loose Crowd
Biological Physics

Synopsis: Cell Sensing Improves in a Loose Crowd

Cells that communicate with each other can measure chemical concentrations with higher precision if they spread out into a sparse configuration.   Read More »

More Articles