Protein ligand
In biochemistry, a protein ligand is an atom, a molecule or an ion which can bind to a specific site (the binding site) on a protein. Alternative names used to mean a protein ligand are affinity reagents or protein binders. To date, antibodies are the most widely used protein ligands in life-science investigations, however, other molecules such as protein scaffolds, nucleic acids, peptides are also being used.
Main methods to study protein–ligand interactions are principal hydrodynamic and calorimetric techniques, and principal spectroscopic and structural methods such as
Other techniques include: fluorescence intensity, bimolecular fluorescence complementation, FRET (fluorescent resonance energy transfer) / FRET quenching surface plasmon resonance, Bio-Layer Interferometry, Coimmunopreciptation indirect ELIS, equilibrium dialysis, gel electrophoresis, far western blot, fluorescence polarization anisotropy, electron paramagnetic resonance, Microscale Thermophoresis
Ligand
In coordination chemistry, a ligand is an ion or molecule (functional group) that binds to a central metal atom to form a coordination complex. The bonding between metal and ligand generally involves formal donation of one or more of the ligand's electron pairs. The nature of metal-ligand bonding can range from covalent to ionic. Furthermore, the metal-ligand bond order can range from one to three. Ligands are viewed as Lewis bases, although rare cases are known to involve Lewis acidic "ligand."
Metals and metalloids are bound to ligands in virtually all circumstances, although gaseous "naked" metal ions can be generated in high vacuum. Ligands in a complex dictate the reactivity of the central atom, including ligand substitution rates, the reactivity of the ligands themselves, and redox. Ligand selection is a critical consideration in many practical areas, including bioinorganic and medicinal chemistry, homogeneous catalysis, and environmental chemistry.
Ligands are classified in many ways, including: charge, size (bulk), the identity of the coordinating atom(s), and the number of electrons donated to the metal (denticity or hapticity). The size of a ligand is indicated by its cone angle.
Podcasts:
