Protein Ligand Registration
Protein Ligand Registration - Related Videos
13:57
Bio-layer Interferometry for Measuring Kinetics of Protein-protein Interactions and Allosteric Ligand Effects
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Cited by 117 •
2014
The protocols here describe kinetic assays of protein-protein interactions with Bio-layer Interferometry. F-type ATP synthase, which is involved in cellular energy metabolism, can be inhibited by its ε subunit in bacteria. We have adapted Bio-layer Interferometry to study interactions of the catalytic complex with ε’s inhibitory C-terminal domain.
03:23
Mobility Shift Affinity Capillary Electrophoresis: A Method to Analyze Sample-Ligand Interactions Depending on Differential Migration of Protein-Ligand Complexes
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2025
This video describes the method to analyze protein-ligand interaction by mobility-shift affinity capillary electrophoresis. This method can be used for characterizing the binding behavior of a protein with various charged ligands.
04:33
Quantitative In-Cell Hydrogen NMR Spectroscopy to Monitor Protein-Ligand Interactions
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2025
In this video, we demonstrate the in-cell nuclear magnetic resonance spectroscopy technique to study protein-ligand interactions between unlabeled overexpressed proteins and small molecules. The successful ligand-protein interaction is confirmed visually by the appearance of an additional set of peaks in the spectral region of interest that gradually replaces the original peaks.
02:40
Ligand Binding Sites
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2020
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...
10:24
Detection of Ligand-activated G Protein-coupled Receptor Internalization by Confocal Microscopy
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Cited by 2 •
2017
This protocol describes confocal microscopy detection of G protein-coupled receptor (GPCR) internalization in mammalian cells. It includes the basic cell culture, transfection, and confocal microscopy procedure and provides an efficient and easily interpretable method to detect the subcellular localization and internalization of fusion-expressed GPCR.
FAQs
Electron-density fitting anchors the ligand model to experimental observations rather than treating its placement as purely nominal. Researchers adjust the ligand’s position and chemical interpretation to match the density, then use geometry restraints during refinement to preserve chemically appropriate relationships. Subsequent validation of protein–ligand contacts helps determine whether the modeled binding site is credible.
Each assignment describes a different aspect of the ligand’s chemical identity. Atom names distinguish individual positions, bond orders represent connections between atoms, and stereochemistry specifies the three-dimensional arrangement of groups. Recording these features explicitly allows the chemical model to correspond consistently with the fitted structure, supporting accurate interpretation of interactions and comparison among complexes.
Chemical descriptors provide a formal representation of the ligand that can be linked to its structural model. Geometry restraints then guide refinement by encoding the expected relationships among atoms, such as the modeled chemical geometry. Together, they reduce ambiguity when experimental density is interpreted and help produce structures that can be evaluated consistently across protein–ligand studies.
The workflow begins by examining the experimental electron density and fitting the small molecule within the protein model. Researchers then assign atom names, bond orders, stereochemistry, and chemical descriptors, followed by generation of geometry restraints. Refinement uses those restraints, while validation checks the resulting protein–ligand contacts before the complex is interpreted or deposited.
Errors in chemical assignment or geometric modeling can make the fitted ligand inconsistent with the experimental density and distort the apparent protein–ligand contacts. Because binding-site interpretation depends on both ligand placement and chemical identity, careful validation is necessary before drawing conclusions from the structure. This is particularly important when structures support affinity studies or drug design.
The process is valuable whenever researchers need to compare, interpret, or reuse protein–ligand structures. Registered ligands support analysis of binding sites, provide a consistent basis for affinity-related structural studies, and contribute to structure-based drug design. Formal encoding also improves deposition and retrieval in structural databases, making complexes easier to compare and helping strengthen reproducibility.