Related Experiment Video

Updated: Oct 23, 2026

Studies of Chaperone-Cochaperone Interactions using Homogenous Bead-Based Assay
06:51

Studies of Chaperone-Cochaperone Interactions using Homogenous Bead-Based Assay

Published on: July 21, 2021

A steric mechanism for inhibition of CO binding to heme proteins

G S Kachalova1, A N Popov, H D Bartunik

  • 1Max-Planck-Arbeitsgruppen für Strukturelle Molekularbiologie, Arbeitsgruppe Proteindynamik, Notkestrabetae 85, 22603 Hamburg, Germany.

Science (New York, N.Y.)
|April 16, 1999
PubMed

Insights

Myoglobin

Area of Science:

  • Biochemistry
  • Structural Biology
  • Biophysics

Background:

  • Myoglobin is a protein that stores oxygen in muscles.
  • Carbon monoxide is a toxic gas that can bind to myoglobin.
  • Understanding how myoglobin binds ligands is important for various biological and medical applications.

Purpose of the Study:

  • To elucidate the structural mechanisms of carbon monoxide binding to myoglobin.
  • To understand how myoglobin reduces its affinity for carbon monoxide.

Main Methods:

  • X-ray crystallography was used to determine the crystal structures of myoglobin.
  • High-resolution (1.15 angstroms) structures were obtained for both deoxy- and carbon monoxide-ligated states.
  • Analysis of structural changes upon ligand binding.

Main Results:

  • Carbon monoxide binding to myoglobin at ambient temperatures requires coordinated movements of the heme, iron atom, and E and F helices.
  • These movements relieve steric hindrance, facilitating ligand binding.
  • This mechanism is crucial for modulating the heme group's affinity for carbon monoxide.

Conclusions:

  • The study reveals the dynamic structural basis for carbon monoxide binding in myoglobin.
  • Heme protein conformational changes play a key role in regulating ligand affinity.
  • These findings provide insights into the interaction of heme proteins with toxic ligands.

More Related Videos

Measurement of Heme Synthesis Levels in Mammalian Cells09:43

Measurement of Heme Synthesis Levels in Mammalian Cells

Published on: July 9, 2015

Structure and Coordination Determination of Peptide-metal Complexes Using 1D and 2D 1H NMR14:44

Structure and Coordination Determination of Peptide-metal Complexes Using 1D and 2D 1H NMR

Published on: December 16, 2013

Related Concept Videos

Enzyme Inhibition01:30

Enzyme Inhibition

Inhibitors are molecules that reduce enzyme activity by binding to the enzyme. In a normally functioning cell, enzymes are regulated by a variety of inhibitors. Drugs and other toxins can also inhibit enzymes. Some inhibitors bind to the enzyme’s active site, while others inhibit enzymatic activity by binding to other sites on the protein structure.
Cooperative Allosteric Transitions01:58

Cooperative Allosteric Transitions

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...
Cooperative Allosteric Transitions01:58

Cooperative Allosteric Transitions

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...
Cooperative Allosteric Transitions01:58

Cooperative Allosteric Transitions

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...
Feedback Inhibition00:46

Feedback Inhibition

Biochemical reactions are occurring constantly in cells, converting starting substances to different products, usually with the help of enzymes that speed the reactions. Without enzymes, it would take far too long for most reactions to occur to be useful to the cell!
Indirect-Acting Cholinergic Agonists: Mechanism of Action01:18

Indirect-Acting Cholinergic Agonists: Mechanism of Action

Indirect-acting cholinergic agonists work by interacting with an enzyme called acetylcholinesterase (AChE) in the synaptic cleft. They can be reversible or irreversible inhibitors and have different effects on the enzyme.
Reversible inhibitors like edrophonium bind to a specific part of the enzyme called the anionic catalytic site. They form noncovalent bonds, which means they are not strongly attached to the enzyme. This creates a temporary and less stable enzyme–inhibitor complex, leading to...