ligand

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Related to Fas ligand: Fas protein, CD95, Fas receptor, Granzyme B

ligand

(lĭg`ənd), charged or uncharged molecule with one or more unshared pairs of electrons that can attach to a central metallic atomatom
[Gr.,=uncuttable (indivisible)], basic unit of matter; more properly, the smallest unit of a chemical element having the properties of that element. Structure of the Atom
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 or ionion,
atom or group of atoms having a net electric charge. Positive and Negative Electric Charges

A neutral atom or group of atoms becomes an ion by gaining or losing one or more electrons or protons.
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 to form an aggregate known as a complex ion (see chemical bondchemical bond,
mechanism whereby atoms combine to form molecules. There is a chemical bond between two atoms or groups of atoms when the forces acting between them are strong enough to lead to the formation of an aggregate with sufficient stability to be regarded as an
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). Some ligands that share electrons with metals form very stable complexes. Some common bases that act as ligands are water and ammonia molecules and halide, hydroxide, acetate, cyanide, thiocyanate, and nitrite anionsanion
, atom or group of atoms carrying a negative charge. The charge results because there are more electrons than protons in the anion. Anions can be formed from nonmetals by reduction (see oxidation and reduction) or from neutral acids (see acids and bases) or polar compounds
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. These ligands are monofunctional, i.e., they are attached by one unshared pair of electrons during complexing. Polyfunctional ligands, which bind to the metal ion with two or more pairs of electrons, are called chelates (see chelating agentschelating agents
. Certain organic compounds are capable of forming coordinate bonds (see chemical bond) with metals through two or more atoms of the organic compound; such organic compounds are called chelating agents.
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). Ethylenediamine-tetraacetate, a commonly used chelating compound, has six pairs of electrons to bind to metal ions. Electron-donating functional groups containing nitrogen, oxygen, sulfur, phosphorous, or carbon may act as ligands in complex biological systems. For example, in enzymes that need complexed metal ions to function, mercapto (sulfur-containing) groups and amino (nitrogen-containing) groups act as chelating agents; these groups fix the metal ion in a specific position. Other biologically important molecules, such as chlorophyll, vitamin B12, and heme, also have nitrogen-containing groups that donate electrons and have a chelating function.

ligand

[′lī·gənd]
(chemistry)
The molecule, ion, or group bound to the central atom in a chelate or a coordination compound; an example is the ammonia molecules in [Co(NH3)6]3+.
References in periodicals archive ?
Different GSK-3[beta] inhibitor doses did not affect the death receptor Fas or its ligand, and the Western blot changes in the Fas and Fas ligand did not mirror the strength of their interaction.
Neutrophils induce apoptosis of lung epithelial cells via release of soluble Fas ligand. Am J Physiol Lung Cell Mol Physiol 2001; 280:L298-305.
of Fas and Fas ligand system-associated apoptosis in gastric cancer.
Interpretation & conclusions: The high levels of sFas antigen and Fas ligand seen in HIV infected individuals suggest increased activation and apoptosis of T cells, due to constant stimulation of the immune system by inter-current infections of HIV infected individuals in south India.
Therapeutic approaches for prevention of lymphocyte apoptosis in murine models of sepsis Strategy Intervention Reference Prevent triggering of Blockade of Fas ligand by using (27) extrinsic pathway Fas fusion protein Prevent triggering of Prevent Fas expression by using (28) extrinsic pathway siRNA Prevent initiation Anti-CD40 agonist antibodies (29) Prevent initiation Treatment with Bcl-2 agonist (30) peptides Prevent triggering of Antiretroviral protease (31) intrinsic pathway inhibitors Prevent execution phase Anticaspase-8 siRNA (28) Prevent execution phase Treatment with caspase (32, 33) inhibitors
Binding of Fas ligand (FasL) to Fas results in caspase 8 activation, which in turn activates and cleaves B cell chronic lymphocytic leukemia/lymphoma 2 (Bcl-2) interacting domain (Bid), a member of the Bcl-2 family.
It inhibits apoptosis and affects Fas ligand expression, essentially instructing tumor cells to tell natural killer cells, "You're supposed to die.
Another element linked to hepatocyte apoptosis is a system consisting of two molecules, Fas and Fas ligand. Fas, also known as CD95, is a type of receptor found on hepatocytes and is similar to one of the receptors for the cytokine TNF-[alpha] (also discussed in the next section).
Earlier research suggested that the interaction between proteins called Fas and Fas ligand (FasL) keeps potentially dangerous maternal immune cells safely away from the embryo (SN: 6/14/97, p.
Furthermore, we could identify Fas ligand (FasL) to be a key player in the cytotoxic and proapoptotic function of [DX5.sup.+]NKT cell potentials.
Nagata, "Human fas ligand: gene structure, chromosomal location and species specificity," International Immunology, vol.
Background: Decoy receptor 3 (DcR3) binds to Fas ligand (FasL) and inhibits FasL-induced apoptosis.