Related Experiment Video
Updated: Feb 12, 2026
10:23
Time-Resolved Fluorescence Anisotropy from Single Molecules for Characterizing Local Flexibility in Biomolecules
Published on: April 25, 2025
1.1K
Spectrally resolved single-molecule electrometry
1Department of Chemistry, University of Zürich, Winterthurerstrasse 190, CH 8057 Zürich, Switzerland.
The Journal of Chemical Physics
|April 2, 2018
Summary
Escape-time electrometry precisely measures single biomolecule charge, revealing conformation and charge distribution. This technique distinguishes subtle molecular differences, like DNA length variations or protein mutations, in one experiment.
Area of Science:
- Biophysics
- Analytical Chemistry
- Molecular Biology
Background:
- Single-molecule measurements offer high precision.
- Escape-time electrometry is a novel technique for charge measurement.
- Molecular charge and conformation influence biological processes.
Purpose of the Study:
- To demonstrate the spectral dimension's utility in escape-time electrometry.
- To distinguish minute charge differences between individual molecules simultaneously.
- To showcase applications in detecting DNA length and protein sequence variations.
Main Methods:
- Utilizing escape-time electrometry in an electrostatic fluidic trap.
- Employing a mean-field model of molecular electrostatics for comparison.
- Leveraging spectral channels for referenced and simultaneous measurements.
Main Results:
- Effective charge measurements correlate with molecular conformation (folded/disordered).
- Non-uniform charge distributions in disordered proteins and polyelectrolytes are detectable.
- Distinguished ~5% length differences in DNA fragments and single amino acid exchanges in prothymosin α.
Conclusions:
- The spectral dimension enhances escape-time electrometry for precise molecular discrimination.
- This method simplifies experimental parameter determination.
- Escape-time electrometry provides insights into molecular structure and sequence variations.
Related Concept Videos
02:38Molecules and Compounds
69.4K
Atoms and Molecules
69.4K
01:32Types of Signaling Molecules
13.3K
In multicellular organisms, many molecules transmit signals between cells to pass information. These signals vary in complexity and include small peptides, nucleotides, steroids, fatty acid derivatives, and dissolved gases such as nitric oxide. Some signaling molecules diffuse through the plasma membrane to act locally between neighboring cells or travel long distances. Others remain attached to the cell surface, transmitting information to other cells only when they make contact. In some...
13.3K
03:48Behavior of Gas Molecules: Molecular Diffusion, Mean Free Path, and Effusion
31.4K
Although gaseous molecules travel at tremendous speeds (hundreds of meters per second), they collide with other gaseous molecules and travel in many different directions before reaching the desired target. At room temperature, a gaseous molecule will experience billions of collisions per second. The mean free path is the average distance a molecule travels between collisions. The mean free path increases with decreasing pressure; in general, the mean free path for a gaseous molecule will be...
31.4K
01:45Positive Regulator Molecules
136.5K
To consistently produce healthy cells, the cell cycle—the process that generates daughter cells—must be precisely regulated.
136.5K
02:39Positive Regulator Molecules
6.9K
Mitotic cell division results in daughter cells that exactly resemble the parent cell. However, errors in the DNA replication or distribution of genetic material may lead to genetic mutations that may be passed down to every new cell formed from the resulting abnormal cell. Propagation of such mutant cells is restricted through checkpoint mechanisms present at different stages of the cell cycle. These checkpoints involve regulator molecules that either promote or demote cell cycle events.
6.9K
01:23Ions, Molecules, and Compounds
15.1K
Ions - When an atom participates in a chemical reaction that results in the donation or acceptance of one or more electrons, the atom becomes positively or negatively charged. This frequently happens for most atoms to have a full valence shell. This can happen either by gaining electrons to fill a shell that is more than half-full or by giving away electrons to empty a shell that is less than half-full, thereby leaving the next smaller electron shell as the new, full valence shell. An atom with...
15.1K