Related Experiment Video
Updated: Jul 14, 2026
10:01
Structure-Guided Design and Development of Novel Cyclophilin A Inhibitors and Ganoderiol-F Derivatives: An In-Silico Approach
Published on: June 23, 2026
Transient ligand docking sites in Cerebratulus lacteus mini-hemoglobin
Pengchi Deng1, Karin Nienhaus, Pasquale Palladino
1Institute of Biophysics, University of Ulm, Albert-Einstein-Allee 11, D-89081 Ulm, Germany.
Gene
|May 29, 2007
Summary
The Cerebratulus lacteus hemoglobin (CerHb) uses a unique apolar channel for oxygen transport. Ligand migration through this channel to a primary docking site is the slowest step in oxygen binding.
Area of Science:
- Biochemistry
- Structural Biology
- Biophysics
Background:
- Monomeric hemoglobin from Cerebratulus lacteus (CerHb) acts as an oxygen storage protein, crucial for maintaining neural function during hypoxia.
- CerHb possesses a large, apolar matrix tunnel, hypothesized to be a pathway for ligand migration to the heme pocket.
Purpose of the Study:
- To investigate the mechanisms of ligand migration and binding within the distal heme pocket of CerHb.
- To elucidate the role of the apolar matrix tunnel in ligand access and transport.
Main Methods:
- Fourier Transform Infrared Spectroscopy with Temperature-Dependent Desorption (FTIR/TDS) at cryogenic temperatures to identify ligand docking sites.
- Flash photolysis experiments at ambient temperatures to determine the kinetics of ligand binding.
Main Results:
- Three transient ligand docking sites (B, C, and D) were identified within the distal heme pocket.
- Site C, adjacent to the heme pocket and connected to the apolar tunnel, is proposed as the primary entry/exit point for ligands.
- Ligand migration through the apolar channel to site C is the rate-limiting step for binding in CerHb.
Conclusions:
- The apolar tunnel and distal heme pocket docking sites play critical roles in the oxygen storage and transport function of CerHb.
- Ligand entry and initial binding are governed by migration through the apolar channel, while subsequent steps to the heme iron are rapid.
Related Concept Videos
00:49Ligand Binding and Linkage
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...
01:49Conserved Binding Sites
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 analyses the...
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 analyses the...
01:49Conserved Binding Sites
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 analyses the...
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 analyses the...
02:40Ligand Binding Sites
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...
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...
02:40Ligand Binding Sites
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...
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...
01:19Allosteric Proteins-ATCase
Binding sites linkages can regulate a protein's function. For example, enzyme activity is often regulated through a feedback mechanism where the end product of the biochemical process serves as an inhibitor.
Aspartate transcarbamoylase (ATCase) is a cytosolic enzyme that catalyzes the condensation of L-aspartate and carbamoyl phosphate to N-carbamoyl-L-aspartate. This reaction is the first step in pyrimidine biosynthesis. UTP and CTP, the end products of the pyrimidine synthesis pathway,...
Aspartate transcarbamoylase (ATCase) is a cytosolic enzyme that catalyzes the condensation of L-aspartate and carbamoyl phosphate to N-carbamoyl-L-aspartate. This reaction is the first step in pyrimidine biosynthesis. UTP and CTP, the end products of the pyrimidine synthesis pathway,...