Jove
Visualize
Contact Us
JoVE
x logofacebook logolinkedin logoyoutube logo
ABOUT JoVE
OverviewLeadershipBlogJoVE Help Center
AUTHORS
Publishing ProcessEditorial BoardScope & PoliciesPeer ReviewFAQSubmit
LIBRARIANS
TestimonialsSubscriptionsAccessResourcesLibrary Advisory BoardFAQ
RESEARCH
JoVE JournalMethods CollectionsJoVE Encyclopedia of ExperimentsArchive
EDUCATION
JoVE CoreJoVE BusinessJoVE Science EducationJoVE Lab ManualFaculty Resource CenterFaculty Site
Terms & Conditions of Use
Privacy Policy
Policies

Related Concept Videos

Structures of Solids02:22

Structures of Solids

17.5K
Solids in which the atoms, ions, or molecules are arranged in a definite repeating pattern are known as crystalline solids. Metals and ionic compounds typically form ordered, crystalline solids. A crystalline solid has a precise melting temperature because each atom or molecule of the same type is held in place with the same forces or energy. Amorphous solids or non-crystalline solids (or, sometimes, glasses) which lack an ordered internal structure and are randomly arranged. Substances that...
17.5K
RNA Structure01:23

RNA Structure

78.9K
Overview
The basic structure of RNA consists of a five-carbon sugar and one of four nitrogenous bases. Although most RNA is single-stranded, it can form complex secondary and tertiary structures. Such structures play essential roles in the regulation of transcription and translation.
Different Types of RNA Have the Same Basic Structure
There are three main types of ribonucleic acid (RNA): messenger RNA (mRNA), transfer RNA (tRNA), and ribosomal RNA (rRNA). All three RNA types consist of a...
78.9K
Structural Isomerism02:34

Structural Isomerism

21.5K
Isomerism in Complexes
Isomers are different chemical species that have the same chemical formula. Structural isomerism of coordination compounds can be divided into two subcategories, the linkage isomers and coordination-sphere isomers.
Linkage isomers occur when the coordination compound contains a ligand that can bind to the transition metal center through two different atoms. For example, the CN− ligand can bind through the carbon atom or through the nitrogen atom. Similarly, SCN− can...
21.5K
Structure of Lipids03:38

Structure of Lipids

98.4K
Lipids include a diverse group of compounds that are largely nonpolar in nature. This is because they are hydrocarbons that include mostly nonpolar carbon-carbon or carbon-hydrogen bonds. Non-polar molecules are hydrophobic (“water fearing”), or insoluble in water. Lipids perform many different functions in a cell. Cells store energy for long-term use in the form of fats. Lipids also provide insulation from the environment for plants and animals. For example, they help keep aquatic...
98.4K
Viral Structure00:56

Viral Structure

74.0K
Viruses are extraordinarily diverse in shape and size, but they all have several structural features in common. All viruses have a core that contains a DNA- or RNA-based genome. The core is surrounded by a protective coat of proteins called the capsid. The capsid is composed of subunits called capsomeres. The capsid and genome-containing core are together known as the nucleocapsid.
74.0K
Antibody Structure01:10

Antibody Structure

65.4K
Overview
Antibodies, also known as immunoglobulins (Ig), are essential players of the adaptive immune system. These antigen-binding proteins are produced by B cells and make up 20 percent of the total blood plasma by weight. In mammals, antibodies fall into five different classes, which each elicits a different biological response upon antigen binding.
The Y-Shaped Structure of Antibodies Consists of Four Polypeptide Chains
Antibodies consist of four polypeptide chains: two identical heavy...
65.4K

You might also read

Related Articles

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

Sort by
Same author

Structural insights into transcription regulation of the global OmpR/PhoB family regulator PhoP from Mycobacterium tuberculosis.

Nature communications·2025
Same author

Structural insights into transcription activation of the <i>Streptomyces</i> antibiotic regulatory protein, AfsR.

iScience·2024
Same author

Structural and functional insights into transcription activation of the essential LysR-type transcriptional regulators.

Protein science : a publication of the Protein Society·2024
Same author

Structural basis of λCII-dependent transcription activation.

Structure (London, England : 1993)·2023
Same author

Structural insights into the transcription activation mechanism of the global regulator GlnR from actinobacteria.

Proceedings of the National Academy of Sciences of the United States of America·2023
Same author

Structural basis for intrinsic transcription termination.

Nature·2023
Same journal

Correction to 'scSuperAnnotator: A platform for benchmarking comparison and visualizing automated cellular annotation methods for scRNA-seq data'.

Nucleic acids research·2026
Same journal

Correction to 'Differentiable partition function calculation for RNA'.

Nucleic acids research·2026
Same journal

Deployment of non-canonical splicing in tunicate genomes is mediated by divergent U2AF function and changing m6A modification in U1 and U6 snRNA.

Nucleic acids research·2026
Same journal

Bacillus subtilis DnaB forms multiple protein-protein interactions essential for DNA replication initiation.

Nucleic acids research·2026
Same journal

Multiple forms of protein-protein and DNA binding are exhibited by BrxC from the BREX phage restriction system.

Nucleic acids research·2026
Same journal

Biosynthesis of glycosylated 5-hydroxycytosine in the DNA of diverse viruses.

Nucleic acids research·2026
See all related articles

Related Experiment Video

Updated: Jan 21, 2026

X-ray Diffraction of Intact Murine Skeletal Muscle as a Tool for Studying the Structural Basis of Muscle Disease
08:26

X-ray Diffraction of Intact Murine Skeletal Muscle as a Tool for Studying the Structural Basis of Muscle Disease

Published on: July 18, 2019

7.8K

Structural basis of σ appropriation.

Jing Shi1, Aijia Wen1, Minxing Zhao2

  • 1Department of Biophysics, and Department of Pathology of Sir Run Run Shaw Hospital, Zhejiang University School of Medicine, Hangzhou 310058, China.

Nucleic Acids Research
|August 9, 2019
PubMed
Summary
This summary is machine-generated.

Bacteriophage T4 uses AsiA and MotA transcription factors to activate middle promoters. A cryo-EM structure reveals AsiA remodels sigma region 4, taking over its function and anchoring DNA for transcription.

More Related Videos

Studying the Neural Basis of Adaptive Locomotor Behavior in Insects
10:19

Studying the Neural Basis of Adaptive Locomotor Behavior in Insects

Published on: April 13, 2011

13.3K
Crystallizing Membrane Proteins for Structure Determination using Lipidic Mesophases
22:00

Crystallizing Membrane Proteins for Structure Determination using Lipidic Mesophases

Published on: November 21, 2010

30.6K

Related Experiment Videos

Last Updated: Jan 21, 2026

X-ray Diffraction of Intact Murine Skeletal Muscle as a Tool for Studying the Structural Basis of Muscle Disease
08:26

X-ray Diffraction of Intact Murine Skeletal Muscle as a Tool for Studying the Structural Basis of Muscle Disease

Published on: July 18, 2019

7.8K
Studying the Neural Basis of Adaptive Locomotor Behavior in Insects
10:19

Studying the Neural Basis of Adaptive Locomotor Behavior in Insects

Published on: April 13, 2011

13.3K
Crystallizing Membrane Proteins for Structure Determination using Lipidic Mesophases
22:00

Crystallizing Membrane Proteins for Structure Determination using Lipidic Mesophases

Published on: November 21, 2010

30.6K

Area of Science:

  • Molecular Biology
  • Structural Biology
  • Microbiology

Background:

  • Bacteriophage T4 middle promoter activation involves AsiA and MotA transcription factors.
  • Understanding the sigma appropriation complex structure is crucial for deciphering transcription activation.

Purpose of the Study:

  • To determine the structure of the intact sigma appropriation complex.
  • To elucidate the mechanism of T4 middle promoter activation.

Main Methods:

  • Single-particle cryo-electron microscopy (cryo-EM) was used.
  • The complex included AsiA, MotA, Escherichia coli RNA polymerase (RNAP), σ70, and a T4 middle promoter.

Main Results:

  • The cryo-EM structure of the intact sigma appropriation complex was determined.
  • AsiA binds and remodels σ70 region 4, preventing host promoter interaction.
  • AsiA undergoes a conformational change, anchors upstream DNA, and replaces σ70 region 4's function.

Conclusions:

  • The structure provides a foundation for understanding sigma appropriation and transcription activation.
  • The findings suggest conserved mechanisms for transcription factor-mediated promoter specificity across bacteria.