3.17:

3.17: קשירת ליגנד והצמדה

Ligand Binding and Linkage

JoVE Core
Cell Biology

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JoVE Core Cell Biology

Ligand Binding and Linkage

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3.14: Turnover Number and Catalytic Efficiency

3.18: Cooperative Allosteric Transitions

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00:49 min

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April 30, 2023

Overview

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 the active site of the protein.

Binding site linkages can cause either positive or negative regulation of ligand binding to other sites. In cases where both ligands prefer to bind to the same conformation of a protein, binding at one site increases the affinity of the other site for its respective ligand. This is known as a positive linkage. On the other hand, if the ligands prefer binding to different conformations, binding of one ligand will make it difficult for the second ligand to bind to the protein. This is known as a negative linkage.

Transcript

Most proteins have multiple locations where ligands can associate, in addition to the site responsible for protein function. Binding of a molecule to any of these sites often results in conformational changes, altering the shape of the protein.

When this change affects the binding of another ligand, the two sites are described as coupled or linked. The binding site linkage can be positively or negatively regulated.

In a positive linkage, the binding of one ligand results in conformational changes that make another site more likely to bind to its respective ligand.

In a negative linkage, the binding of one ligand results in conformational changes that prevent another binding site from associating with its ligand.

Key Terms and definitions

Orthosteric Binding Site - The primary location where ligands bind on a protein.
Allosteric Regulation - Process of modulating proteins using effector molecules.
Linkages - Chemical bonds that hold molecules together in a complex.
En Ligand - A molecule that binds to another (typically larger) molecule.
Allosteric Proteins - Proteins with a secondary binding site affecting its activity.

Learning Objectives

Define Ligand - Explain its role in biological systems (e.g., binding to proteins).
Contrast Orthosteric vs Allosteric Binding - Highlight differences (e.g., binding location).
Explore Protein Regulation - Describe how allosteric regulation works (e.g., effector molecules).
Explain Linkages - Discuss their function in molecular structures.
Apply Concepts to Biological Context - Understand how these processes affect life forms.

Questions that this video will help you answer

What is a ligand and how does it interact with proteins?
How are orthosteric and allosteric binding different?
How does allosteric regulation control protein function?

This video is also useful for

Students - Understanding ligands and their function enhances knowledge in biology
Educators - Provides a clear concept, making it easier to teach biological processes
Researchers - Important for studies focusing on protein-binding and functions
Science Enthusiasts - Offers insights into biological mechanisms and their implications

Tags

להלן מילות המפתח מהטקסט הנתון: כריכת ליגנד הצמדה