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


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

Viewpoint: Putting Bounds on Biochemical Noise
Biological Physics

Viewpoint: Putting Bounds on Biochemical Noise

Biochemical networks are often poorly characterized, but researchers can still derive limits on the level of the random variations or noise in different network components. Read More »

Focus: Bumblebees In Turbulence
Biological Physics

Focus: Bumblebees In Turbulence

A simulation of a flying bee shows that insects don’t expend extra energy to maintain lift in turbulent air flow. Read More »

Viewpoint: A One-Sided View of Acoustic Traps
Biological Physics

Viewpoint: A One-Sided View of Acoustic Traps

Using new techniques for shaping sound waves from a single source, researchers have made acoustic tweezers that move particles around in three dimensions. Read More »

More Articles