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

Multi-Step Reactions02:31

Multi-Step Reactions

7.5K
Chemical reactions often occur in a stepwise fashion involving two or more distinct reactions taking place in a sequence. A balanced equation indicates the reacting species and the product species, but it reveals no details about how the reaction occurs at the molecular level. The reaction mechanism (or reaction path) provides details regarding the precise, step-by-step process by which a reaction occurs. Each of the steps in a reaction mechanism is called an elementary reaction. These...
7.5K
ATP Synthase: Mechanism01:48

ATP Synthase: Mechanism

16.0K
In animals, the mitochondrial F1F0 ATP synthase is the key protein that synthesizes ATP molecules through a complex catalytic mechanism. While the nuclear genome encodes the majority of ATP synthase subunits, the mitochondrial genome encodes some of the enzyme's most critical components. The formation of this multi-subunit enzyme is a complex multi-step process regulated at the level of transcription, translation, and assembly. Defects in one or more of these steps can result in decreased...
16.0K
Cooperative Allosteric Transitions01:58

Cooperative Allosteric Transitions

1.8K
1.8K
Cooperative Allosteric Transitions01:58

Cooperative Allosteric Transitions

2.3K
2.3K
Cooperative Allosteric Transitions01:58

Cooperative Allosteric Transitions

7.4K
Cooperative allosteric transitions can occur in multimeric proteins, where each subunit of the protein has its own ligand-binding site. When a ligand binds to any of these subunits, it triggers a conformational change that affects the binding sites in the other subunits; this can change the affinity of the other sites for their respective ligands. The ability of the protein to change the shape of its binding site is attributed to the presence of a mix of flexible and stable segments in the...
7.4K
Step-Growth Polymerization: Overview01:03

Step-Growth Polymerization: Overview

3.6K
Step-growth or condensation polymerization is a stepwise reaction of bi or multifunctional monomers to form long-chain polymers. As all the monomers are reactive, most of the monomers are consumed at the early stages of the reaction to form small chains of reactive oligomers, which then combine to form long polymer chains in the late stages. Hence, the reaction has to proceed for a long time to achieve high molecular weight polymers.
Many natural and synthetic polymers are produced by...
3.6K

You might also read

Related Articles

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

Sort by
Same author

Solution-state nuclear magnetic resonance studies of the <i>Salmonella typhimurium</i> tryptophan synthase complex.

Biochemistry and biophysics reports·2026
Same author

Structure, Function and Inhibition of Helicases Involved in Virus Infection.

Biomolecules·2026
Same author

Multivalent Interactions Between the Picornavirus 3C(D) Main Protease and RNA Oligonucleotides Induce Liquid-Liquid Phase Separation.

Viruses·2025
Same author

Molecular determinants of picornavirus 3C protease binding to phosphoinositide-enriched lipid membranes.

The Journal of biological chemistry·2025
Same author

Editorial: Allosteric functions and inhibitions: structural insights.

Frontiers in molecular biosciences·2024
Same author

Picornavirus 3C Proteins Intervene in Host Cell Processes through Proteolysis and Interactions with RNA.

Viruses·2023

Related Experiment Video

Updated: May 4, 2026

Steady-state, Pre-steady-state, and Single-turnover Kinetic Measurement for DNA Glycosylase Activity
14:27

Steady-state, Pre-steady-state, and Single-turnover Kinetic Measurement for DNA Glycosylase Activity

Published on: August 19, 2013

18.8K

Loop-loop interactions govern multiple steps in indole-3-glycerol phosphate synthase catalysis.

Margot J Zaccardi1, Kathleen F O'Rourke, Eric M Yezdimer

  • 1Department of Chemistry, The Pennsylvania State University, University Park, Pennsylvania, 16802.

Protein Science : a Publication of the Protein Society
|January 10, 2014
PubMed
Summary

Mutations in key residues of indole-3-glycerol phosphate synthase (IGPS) alter enzyme dynamics and catalysis. This research highlights the critical role of the β1α1 loop

Keywords:
amino acid networksenzyme kineticsenzyme mechanismsmetabolismnuclear magnetic resonanceprotein dynamicsprotein engineeringstatistical coupling analysis

More Related Videos

Studying DNA Looping by Single-Molecule FRET
11:27

Studying DNA Looping by Single-Molecule FRET

Published on: June 28, 2014

14.8K
Light-Controlled Fermentations for Microbial Chemical and Protein Production
08:37

Light-Controlled Fermentations for Microbial Chemical and Protein Production

Published on: March 22, 2022

3.8K

Related Experiment Videos

Last Updated: May 4, 2026

Steady-state, Pre-steady-state, and Single-turnover Kinetic Measurement for DNA Glycosylase Activity
14:27

Steady-state, Pre-steady-state, and Single-turnover Kinetic Measurement for DNA Glycosylase Activity

Published on: August 19, 2013

18.8K
Studying DNA Looping by Single-Molecule FRET
11:27

Studying DNA Looping by Single-Molecule FRET

Published on: June 28, 2014

14.8K
Light-Controlled Fermentations for Microbial Chemical and Protein Production
08:37

Light-Controlled Fermentations for Microbial Chemical and Protein Production

Published on: March 22, 2022

3.8K

Area of Science:

  • Biochemistry and Molecular Biology
  • Enzyme kinetics and mechanism
  • Protein dynamics and structure-function relationships

Background:

  • Indole-3-glycerol phosphate synthase (IGPS) is crucial for tryptophan biosynthesis.
  • The catalytic function of IGPS depends on the dynamic movement of its active-site β1α1 loop.
  • Covarying residues in the β1α1 and β2α2 loops (Arg54 and Asn90) were predicted to coordinate loop motions.

Purpose of the Study:

  • To investigate the functional and dynamic roles of covarying residues (Arg54 and Asn90) in IGPS.
  • To test the hypothesis that these residues coordinate functional motions of the β1α1 and β2α2 loops.

Main Methods:

  • Site-directed mutagenesis of Arg54 and Asn90 in Sulfolobus sulfataricus IGPS (ssIGPS).
  • Characterization of catalytic function using steady-state kinetics, solvent viscosity, and kinetic isotope effects.
  • Analysis of protein stability and structural dynamics using nuclear magnetic resonance (NMR) spectroscopy.

Main Results:

  • Mutations showed modest changes in steady-state kinetics but altered the rate-determining step.
  • The N90A substitution significantly impacted general acid/base catalysis, affecting the pH rate profile.
  • NMR studies revealed quenching of ps-ns and µs-ms timescale motions in the β1α1 loop upon mutation.

Conclusions:

  • The study provides structural, dynamic, and functional evidence for the coevolution of β1α1 and β2α2 loop residues.
  • Mutations in covarying residues disrupt the coordinated dynamics essential for IGPS catalysis.
  • The β1α1 loop plays multiple roles in IGPS catalysis, regulated by interactions with other structural elements.