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

Conserved Binding Sites01:49

Conserved Binding Sites

5.2K
Many proteins’ biological role depends on their interactions with their ligands, small molecules that bind to specific locations on the protein known as ligand-binding sites. Ligand-binding sites are often conserved among homologous proteins as these sites are critical for protein function.
Binding sites are often located in large pockets, and if their location on a protein’s surface is unknown, it can be predicted using various approaches. The energetic method computationally...
5.2K
Cooperative Binding of Transcription Regulators02:13

Cooperative Binding of Transcription Regulators

7.4K
Transcriptional regulators bind to specific cis-regulatory sequences in the DNA to regulate gene transcription. These cis-regulatory sequences are very short, usually less than ten nucleotide pairs in length. The short length means that there is a high probability of the exact same sequence randomly occurring throughout the genome.  Since regulators can also bind to groups of similar sequences, this further increases the chances of random binding. Transcriptional regulators form...
7.4K
Ligand Binding and Linkage00:49

Ligand Binding and Linkage

5.7K
Allosteric proteins have more than one ligand binding site; the binding of a ligand to any of these sites influences the binding of ligands to the other sites. When a protein is allosteric, its binding sites are called coupled or linked.  In the case of enzymes, the site that binds to the substrate is known as the active site and the other site is known as the regulatory site. When a ligand binds to the regulatory site, this leads to conformational changes in the protein that can influence...
5.7K
Protein Folding Quality Check in the RER01:29

Protein Folding Quality Check in the RER

5.4K
ER is the primary site for the maturation and folding of soluble and transmembrane secretory proteins. The calnexin cycle is a specific chaperone system that folds and assesses the confirmation of N-glycosylated proteins before they can exit the ER lumen. The primary players of this quality check pipeline are the lectins, ER-resident chaperones, and a glucosyl transferase enzyme. In case the calnexin system in the lumen fails to salvage a misfolded protein, it is transported to the cytoplasm...
5.4K
Ligand Binding Sites02:40

Ligand Binding Sites

15.4K
Proteins are dynamic macromolecules that carry out a wide variety of essential processes; however, the activities of most proteins depend on their interactions with other molecules or ions, known as ligands.
Protein-ligand interactions are quite specific; even though numerous potential ligands surround a cellular protein at any given time, only a particular ligand can bind to that protein. Moreover, a ligand binds only to a dedicated area on the surface of the protein, known as the...
15.4K
Multi-pass Transmembrane Proteins and β-barrels01:09

Multi-pass Transmembrane Proteins and β-barrels

6.7K
In multi-pass transmembrane proteins, the polypeptide chain crosses the membrane more than once. The transmembrane polypeptide chain either forms an α-helix or β-strand structure. α-Helix containing multi-pass transmembrane proteins are ubiquitous, whereas β-strand containing ones are mainly found in gram-negative bacteria, mitochondria, and chloroplasts.
α-Helix containing multi-pass transmembrane proteins
Multi-pass transmembrane proteins such as...
6.7K

You might also read

Related Articles

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

Sort by
Same author

To the editor, response letter.

Clinical & translational oncology : official publication of the Federation of Spanish Oncology Societies and of the National Cancer Institute of Mexico·2021
Same author

Recommendations of the Spanish brachytherapy group (GEB) of Spanish Society of Radiation Oncology (SEOR) and the Spanish Society of Medical Physics (SEFM) for high-dose rate (HDR) non melanoma skin cancer brachytherapy.

Clinical & translational oncology : official publication of the Federation of Spanish Oncology Societies and of the National Cancer Institute of Mexico·2017
Same author

Fetal dose measurements and shielding efficiency assessment in a custom setup of (192)Ir brachytherapy for a pregnant woman with breast cancer.

Physica medica : PM : an international journal devoted to the applications of physics to medicine and biology : official journal of the Italian Association of Biomedical Physics (AIFB)·2015
Same author

European doctorate in biotechnology: Added value for european academia and industry.

Biochemistry and molecular biology education : a bimonthly publication of the International Union of Biochemistry and Molecular Biology·2011
Same author

The anti-DNA story.

Lupus·2010
Same author

A systematic approach to vaccine complexity using an automaton model of the cellular and humoral immune system. I. Viral characteristics and polarized responses.

Vaccine·2000
Same journal

Aromatic Cage-Directed Azide-Methyllysine Photochemistry for Profiling Nonhistone Interacting Partners of the MeCP2 Methyl-CpG-Binding Domain.

Biochemistry·2026
Same journal

Differential Hydroxypyruvate Processing by <i>E. coli</i> and <i>P. aeruginosa</i> DXP Synthases Reveals Preferential Xylulose 5-Phosphate Formation by the <i>P. aeruginosa</i> Enzyme.

Biochemistry·2026
Same journal

Structural and Functional Characterization of Heterologous Nitrogenase Complexes.

Biochemistry·2026
Same journal

Discovery of Bacterial Unspecific Peroxygenases.

Biochemistry·2026
Same journal

Lactate Biology: Subcellular Routing and Chemical Form Define Function.

Biochemistry·2026
Same journal

Nature's Anaerobic Toolkit: Glycyl Radical Enzymes and Their Expanding Functional and Mechanistic Diversity.

Biochemistry·2026
See all related articles

Related Experiment Video

Updated: Feb 28, 2026

Author Spotlight: Exploring Cellular Processes by Modeling Ligands in Cryo-EM Maps
09:30

Author Spotlight: Exploring Cellular Processes by Modeling Ligands in Cryo-EM Maps

Published on: July 19, 2024

2.2K

A dimer--dimer binding region in beta-galactosidase

F Celada, I Zabin

    Biochemistry
    |February 6, 1979
    PubMed
    Summary
    This summary is machine-generated.

    Alpha complementation restores beta-galactosidase activity using the alpha donor fragment (CNBr2). This study identifies a dimer-dimer binding region within the enzyme, crucial for its tetrameric structure and function.

    More Related Videos

    Author Spotlight: Unveiling the Structural and Dynamic Aspects of Glycan Molecular Recognition
    07:40

    Author Spotlight: Unveiling the Structural and Dynamic Aspects of Glycan Molecular Recognition

    Published on: May 17, 2024

    2.0K
    Transmembrane Domain Oligomerization Propensity determined by ToxR Assay
    06:45

    Transmembrane Domain Oligomerization Propensity determined by ToxR Assay

    Published on: May 26, 2011

    15.7K

    Related Experiment Videos

    Last Updated: Feb 28, 2026

    Author Spotlight: Exploring Cellular Processes by Modeling Ligands in Cryo-EM Maps
    09:30

    Author Spotlight: Exploring Cellular Processes by Modeling Ligands in Cryo-EM Maps

    Published on: July 19, 2024

    2.2K
    Author Spotlight: Unveiling the Structural and Dynamic Aspects of Glycan Molecular Recognition
    07:40

    Author Spotlight: Unveiling the Structural and Dynamic Aspects of Glycan Molecular Recognition

    Published on: May 17, 2024

    2.0K
    Transmembrane Domain Oligomerization Propensity determined by ToxR Assay
    06:45

    Transmembrane Domain Oligomerization Propensity determined by ToxR Assay

    Published on: May 26, 2011

    15.7K

    Area of Science:

    • Biochemistry
    • Molecular Biology
    • Enzymology

    Background:

    • Alpha complementation is a method to restore activity to inactive M15 beta-galactosidase protein.
    • The M15 protein is a dimer lacking specific residues and requires an alpha donor fragment for activity.

    Purpose of the Study:

    • To identify the dimer-dimer binding region involved in beta-galactosidase alpha complementation.
    • To investigate the structural basis of enzyme activity restoration.

    Main Methods:

    • Proteolytic digestion of native and denatured beta-galactosidase using trypsin.
    • Cyanogen bromide cleavage to generate peptide fragments.
    • Immunological studies using antibodies against specific peptide fragments (CNBr2, T8, CNBr3).
    • Assay of alpha complementation activity.

    Main Results:

    • Intact CNBr2 (residues 3-92) was obtained from native beta-galactosidase, indicating this segment is buried in the folded protein.
    • Antibodies against CNBr2 and T8 bound to the M15 protein dimer, suggesting this region is exposed.
    • Anti-CNBr2 antibodies inhibited alpha-complemented enzyme formation, implicating CNBr2 in dimer-dimer interactions.

    Conclusions:

    • The alpha donor fragment (CNBr2) is involved in the dimer-dimer interactions necessary for forming the active tetrameric beta-galactosidase.
    • Structural studies using proteolysis and immunology reveal key regions for protein assembly and function.