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


More Features »


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

Focus: Probing Cell Squishiness

Focus: Probing Cell Squishiness

A new atomic force microscopy technique can map the elastic properties of living cells. Read More »

Synopsis: Twisting DNA Locates its Defects
Biological Physics

Synopsis: Twisting DNA Locates its Defects

Single base-pair mismatches in DNA can be pinpointed by twisting the molecule until it buckles. Read More »

Synopsis: Teaching Fish How to Swim
Fluid Dynamics

Synopsis: Teaching Fish How to Swim

A new model of swimming fish and cetaceans pinpoints the parameters that matter most for efficient motion. Read More »

More Articles