Search research articles

ABOUT JoVE

Overview Leadership Blog JoVE Help Center

AUTHORS

Publishing Process Editorial Board Scope & Policies Peer Review FAQ Submit

LIBRARIANS

Testimonials Subscriptions Access Resources Library Advisory Board FAQ

RESEARCH

JoVE Journal Methods Collections JoVE Encyclopedia of Experiments Archive

EDUCATION

JoVE Core JoVE Business JoVE Science Education JoVE Lab Manual Faculty Resource Center Faculty Site

Terms & Conditions of Use

Related Concept Videos

Polymer Classification: Crystallinity

Polymer Classification: Crystallinity

Unlike ionic or small covalent molecules, polymers do not form crystalline solids due to the diffusion limitations of their long-chain structures. However, polymers contain microscopic crystalline domains separated by amorphous domains.
Crystalline domains are the regions where polymer chains are aligned in an orderly manner and held together in proximity by intermolecular forces. For example, chains in the crystalline domains of polyethylene and nylon are bound together by van der Waals...

Crystal Growth: Principles of Crystallization

Crystal Growth: Principles of Crystallization

Crystallization is a phase transformation process in which crystals are precipitated from a supersaturated solution or formed from other sources. During crystallization, atoms or molecules arrange themselves into a well-defined, rigid crystal lattice to minimize energy.
Initiating crystallization involves manipulating the concentration of the solute and the temperature of the solution. Since crystal growth occurs when the ratio of concentration and solubility of the solute in the solvent – the...

Determination of Crystal Structures

Determination of Crystal Structures

In the late 1800s, the revelation that light extended beyond visible wavelengths led to the discovery of X-rays by Wilhelm Roentgen. Recognized as high-energy electromagnetic radiation with short wavelengths, X-rays prompted exploration into their interaction with crystals. Max von Laue proposed in 1912 that the periodic arrangement of atoms, ions, or molecules in crystals would cause them to diffract X-rays, a hypothesis confirmed through experiments with copper sulfate and zinc sulfide...

$X-ray Diffraction of Biological Samples$ 01:10

X-ray Diffraction of Biological Samples

X-ray diffraction or XRD is an analytical tool that utilizes X-rays to study ordered structures such as crystalline organic and inorganic samples, polycrystalline materials, proteins, carbohydrates, and drugs.
According to Bragg's law, when X-rays strike the sample positioned on a stage, the rays are scattered by the electron clouds around the sample atoms. The X-ray diffraction or scattering is caused by constructive interference of the X-ray waves that reflect off the internal crystal...

X-ray Crystallography

X-ray Crystallography

The size of the unit cell and the arrangement of atoms in a crystal may be determined from measurements of the diffraction of X-rays by the crystal, termed X-ray crystallography.
Diffraction
Diffraction is the change in the direction of travel experienced by an electromagnetic wave when it encounters a physical barrier whose dimensions are comparable to those of the wavelength of the light. X-rays are electromagnetic radiation with wavelengths about as long as the distance between neighboring...

Recrystallization: Solid–Solution Equilibria

Recrystallization: Solid–Solution Equilibria

Recrystallization is a purification technique used to separate impurities from solid compounds. In this technique, no chemical reactions occur. Instead, it exploits physical properties only, specifically, the solubility differences between the desired compound and impurities, either at a single temperature or at different temperatures, and under other selected conditions. The solid-solution equilibrium (solubility equilibrium) of each component in the solution represents a binary phase...

You might also read

Related Articles

Articles linked to this work by shared authors, journal, and citation graph.

Sort by

Same author

Revised microbiology core knowledge objectives for modern undergraduate medical education.

Journal of microbiology & biology education·2026

Same author

Patient-perceived factors influencing physical activity sensor use in stroke prevention and rehabilitation: A thematic synthesis protocol.

PloS one·2024

Same author

A Moonlighting Enolase from Lactobacillus gasseri does not Require Enzymatic Activity to Inhibit Neisseria gonorrhoeae Adherence to Epithelial Cells.

Probiotics and antimicrobial proteins·2015

Same author

Crystal structure of an efficacious gonococcal adherence inhibitor: an enolase from Lactobacillus gasseri.

FEBS letters·2014

Same author

The 1.59Å resolution structure of the minor pseudopilin EpsH of Vibrio cholerae reveals a long flexible loop.

Biochimica et biophysica acta·2013

Same author

Expression, purification, crystallization and preliminary X-ray studies of Lactobacillus jensenii enolase.

Acta crystallographica. Section F, Structural biology and crystallization communications·2010

Search research articles

Related Experiment Video

Updated: Jun 13, 2026

An All-in-one Sample Holder for Macromolecular X-ray Crystallography with Minimal Background Scattering

An All-in-one Sample Holder for Macromolecular X-ray Crystallography with Minimal Background Scattering

Published on: July 6, 2019

Trial by fire: are the crystals macromolecules?

Kannan Raghunathan¹, Paul T Harris, Dennis N Arvidson

¹Michigan State University, Department of Microbiology and Molecular Genetics, USA.

Acta Crystallographica. Section F, Structural Biology and Crystallization Communications

|May 7, 2010

Summary

Distinguishing protein crystals from salt crystals is crucial in structural biology. A simple flame test effectively differentiates macromolecule crystals, which are destroyed, from salt crystals, which remain intact.

More Related Videos

Automated Protocols for Macromolecular Crystallization at the MRC Laboratory of Molecular Biology

Automated Protocols for Macromolecular Crystallization at the MRC Laboratory of Molecular Biology

Published on: January 24, 2018

Crystallization and Structural Determination of an Enzyme:Substrate Complex by Serial Crystallography in a Versatile Microfluidic Chip

Crystallization and Structural Determination of an Enzyme:Substrate Complex by Serial Crystallography in a Versatile Microfluidic Chip

Published on: March 20, 2021

Related Experiment Videos

Last Updated: Jun 13, 2026

An All-in-one Sample Holder for Macromolecular X-ray Crystallography with Minimal Background Scattering

An All-in-one Sample Holder for Macromolecular X-ray Crystallography with Minimal Background Scattering

Published on: July 6, 2019

Automated Protocols for Macromolecular Crystallization at the MRC Laboratory of Molecular Biology

Automated Protocols for Macromolecular Crystallization at the MRC Laboratory of Molecular Biology

Published on: January 24, 2018

Crystallization and Structural Determination of an Enzyme:Substrate Complex by Serial Crystallography in a Versatile Microfluidic Chip

Crystallization and Structural Determination of an Enzyme:Substrate Complex by Serial Crystallography in a Versatile Microfluidic Chip

Published on: March 20, 2021

Area of Science:

Structural biology
Biochemistry
Crystallography

Background:

Protein crystallization is essential for determining protein structure.
Crystallization screens often produce both protein and salt crystals, complicating analysis.
Differentiating between these crystal types is critical for successful structure determination.

Purpose of the Study:

To introduce a simple and rapid method for distinguishing protein crystals from salt crystals.
To provide a practical technique for researchers working with protein crystallization.

Main Methods:

A crystal or crystals from a crystallization drop are transferred to a glass coverslip.
The coverslip is then passed through the flame of a Bunsen burner.
Observation of crystal integrity after flame exposure determines its composition.

Main Results:

Macromolecule (protein) crystals are destroyed or significantly altered by the flame treatment.
Salt crystals generally remain intact after exposure to the flame.
This flame test is compatible with other standard crystal testing methods like crushing and staining.

Conclusions:

The flame test offers a straightforward and effective way to identify salt crystals in protein crystallization experiments.
This method aids in the rapid assessment of crystal identity, saving time and resources in structural biology research.