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

Focus: A Physical Model for Neurodegenerative Disease
Biological Physics

Focus: A Physical Model for Neurodegenerative Disease

Computer simulations of the diffusion and aggregation of harmful proteins in the brain reproduce the pattern of damage seen in several neurodegenerative diseases. Read More »

Focus: How to Measure Viscosity Inside Cells
Biological Physics

Focus: How to Measure Viscosity Inside Cells

A noninvasive method measures the viscosity in a cell nucleus by observing the movement and fusion of cellular components. Read More »

Synopsis: Three Pulses for Clearer Ultrasound Images
Biological Physics

Synopsis: Three Pulses for Clearer Ultrasound Images

Researchers have figured out how to improve contrast and reduce background noise in ultrasound images acquired with a technique that uses air-filled protein structures. Read More »

More Articles