A tetramer is a protein with four subunits (tetrameric). There are homo-tetramers (all subunits are identical) such as glutathione S-transferase or single-strand binding protein, dimers of hetero-dimers such as haemoglobin (a dimer of an alpha/beta dimer), and hetero-tetramers, where each subunit is different.

In Immunology, MHC tetramers can be used to quantitate numbers of antigen-specific T cells (especially CD8+ T cells). MHC tetramers are based on recombinant class I molecules that, through the action of bacterial BirA, have been biotinylated. These molecules are folded with the peptide of interest and β2M and tetramerized by a fluorescently labeled streptavidin. (Streptavidin binds to four biotins per molecule.) This tetramer reagent will specifically label T cells that express T cell receptors that are specific for a given peptide-MHC complex. For example, a Kb/FAPGNYPAL tetramer will specifically bind to Sendai virus specific CTL in a C57BL/6 mouse. Antigen specific responses can be measured as CD8+, tetramer+ T cells as a fraction of all CD8+ lymphocytes.

The reason for using a tetramer, as opposed to a single labeled MHC class I molecule is that the tetrahedral tetramers can bind to three TCRs at once, allowing specific binding in spite of the low (10-6 molar) affinity of the typical class I-peptide-TCR interaction.MHC Class II tetramers can also be made although these are more difficult to work with practically.

Wikimedia Foundation. 2010.

Игры ⚽ Поможем написать реферат

Look at other dictionaries:

  • tetramer — tetramér adj. m., pl. tetraméri; f. sg. tetraméră, pl. tetramére Trimis de siveco, 10.08.2004. Sursa: Dicţionar ortografic  TETRAMÉR, Ă adj. Constituit din patru părţi; (biol.) care se divide în pa …   Dicționar Român

  • tetramer — oligomer o*lig o*mer, n. (Chem.) A molecule composed of a small number of linked monomer units; a short polymer; compounds called oligomers have less than one hundred monomer units and usually less than thirty. Oligomers of increasing length are… …   The Collaborative International Dictionary of English

  • tetramer — tetrameras statusas T sritis chemija apibrėžtis Keturių vienodų molekulių susijungimo produktas. atitikmenys: angl. tetramer rus. тетрамер …   Chemijos terminų aiškinamasis žodynas

  • Tetramer assay — A tetramer assay is used to detect the presence of antigen specific T cells. In order for a T cell to detect the peptide to which it is specific, it must both recognize the peptide AND the MHC complex at the surface of a cell it comes into… …   Wikipedia

  • tetramer — noun Date: 1929 a molecule (as an enzyme or a polymer) that consists of four structural subunits (as peptide chains or condensed monomers) • tetrameric adjective …   New Collegiate Dictionary

  • Tetramer — Das Suffix mer (griech. meros, Teil) findet vor allem in Chemie und Biochemie zur allgemeinen Benennung von Molekülen Verwendung. Bei einer Reihe von Molekülen, die sich aus einer überschaubaren Anzahl von Untereinheiten zusammensetzen, wird ein… …   Deutsch Wikipedia

  • tetramer — /te treuh meuhr/, n. 1. a molecule composed of four identical, simpler molecules. 2. a polymer derived from four identical monomers. Cf. oligomer. [1905 10; TETRA + MER] * * * …   Universalium

  • tetramer — noun An oligomer having four subunits …   Wiktionary

  • Tetramer — Te|t|ra|mer [↑ tetra (2) u. ↑ mer] ↑ Oligomer. * * * te|t|ra|mer <Adj.> [zu griech. méros = Teil] (Bot.): (von ↑ Wirteln 2) viergliederig. * * * te|tra|mer <Adj.> [zu griech. méros = Teil] (Bot.): (von Wirteln 2 …   Universal-Lexikon

  • tetramer — tet·ra·mer te trə mər n a molecule (as an enzyme or a polymer) that consists of four structural subunits (as peptide chains or condensed monomers) tet·ra·mer·ic .te trə mer ik adj * * * tet·ra·mer (tetґrə mur″) a compound composed of… …   Medical dictionary

Share the article and excerpts

Direct link
Do a right-click on the link above
and select “Copy Link”