Dimerization: Difference between revisions

Browse history interactively ← Previous edit Next edit →Content deleted Content addedVisual WikitextInline

Revision as of 16:44, 24 July 2006 editPi.1415926535 (talk \| contribs)Autopatrolled, Extended confirmed users, New page reviewers49,079 editsm added chemistry stub← Previous edit		Revision as of 02:42, 25 July 2006 edit undoCacycle (talk \| contribs)Extended confirmed users21,982 edits biology section newNext edit →
Line 1:		Line 1:
	], or common table sugar, is composed of glucose and fructose.]]		], or common table sugar, is composed of glucose and fructose.]]

	==Chemistry==		== Chemistry ==

	In ], a '''dimer''' refers to a ] composed of two similar subunits or monomers linked together. It is a special case of a ]. It can refer to halide chemistry, involving halogen bonding. Its more common usage refers to dimers as certain types of ]: ], for example, is a dimer of a ] molecule and a ] molecule.		In ], a '''dimer''' refers to a ] composed of two similar subunits or monomers linked together. It is a special case of a ]. It can refer to halide chemistry, involving halogen bonding. Its more common usage refers to dimers as certain types of ]: ], for example, is a dimer of a ] molecule and a ] molecule.

	A '''physical dimer''' is a term that designates the case where intermolecular interaction brings two identical molecules closer together than other molecules. There are no ]s between the physical dimer molecules. ] is such a case where ]s provide the interaction.		A '''physical dimer''' is a term that designates the case where intermolecular interaction brings two identical molecules closer together than other molecules. There are no ]s between the physical dimer molecules. ] is such a case where ]s provide the interaction.

	==~~Biology~~==		== Biochemistry ==
	] which has folded back upon itself is an example of a homodimer]]
	In ], particularly molecular and cellular biology, dimers are most often observed in signaling. They are crucial to understanding chemical reactions in biochemistry as well. In this case, a dimer is a ] complex made up of two subunits that are not necessarily ] linked. In fact, they may initially be ] proteins. These monomers will dimerize, or join together, usually upon the binding of a signal to the receptor of each monomer. These signals can be a growth factor, a phosphate group from ] (usually through a kinase protein), or a ].

			In ] and ], dimers of ]s like ]s and ]s are often observed. The dimerization of identical subunits is called '''homodimerization''', the dimerization of different subunits or unrelated ]s is called '''heterodimerization'''. Most dimers in biochemistry are not connected by ]s with the exception of ]s.
	An example of this dimerizing activity involves the RAS-independent receptor tyrosine ] that activates Phospholipase C-gamma. When a growth factor binds to two monomeric Epithelial Growth Factor (EGF) receptor (or Platelet-Derived Growth Factor (PDGF) receptor), the receptors will dimerize and phosphorylate each other at the SH2 binding domains on the cytoplasmic portion of the receptor. The Phospholipase C-gamma isoform has SH2 domains that bind to the newly phosphorylated SH2 binding domain of the dimerized growth factor receptors. Upon binding, the Phospholipase C-gamma will be activated, and will be close to the membrane phospholipid that it is designed to cleave.

			=== Examples ===
	In a '''homodimer''' the two subunits are identical, and in a '''heterodimer''' they differ (though they are often still very similar in structure).

			* ]s:
			** ]
			* ]s
			** ]
			** ]s
			*** ]s
			** ]s
			*** ] motif proteins
			*** ]s
			** ]s
			** ]s
			** ] βγ-subunit dimer
			** ]
			** ] (TIM)
			** ]
			** ]
			** ]
			** ]
			** ]

	== See also ==		== See also ==

			* ]
			* ]
	* ]		* ]
	* ]		* ]
Line 28:		Line 50:

	{{biochem-stub}}		{{biochem-stub}}

	{{Cell-biology-stub}}		{{Cell-biology-stub}}

	{{Chemistry-stub}}		{{Chemistry-stub}}

Revision as of 02:42, 25 July 2006

Sucrose, or common table sugar, is composed of glucose and fructose.

Chemistry

In chemistry, a dimer refers to a molecule composed of two similar subunits or monomers linked together. It is a special case of a polymer. It can refer to halide chemistry, involving halogen bonding. Its more common usage refers to dimers as certain types of sugar: sucrose, for example, is a dimer of a glucose molecule and a fructose molecule.

A physical dimer is a term that designates the case where intermolecular interaction brings two identical molecules closer together than other molecules. There are no covalent bonds between the physical dimer molecules. Acetic acid is such a case where hydrogen bonds provide the interaction.

Biochemistry

In biochemistry and molecular biology, dimers of macromolecules like proteins and nucleic acids are often observed. The dimerization of identical subunits is called homodimerization, the dimerization of different subunits or unrelated monomers is called heterodimerization. Most dimers in biochemistry are not connected by covalent bonds with the exception of disulfide bridges.

Examples

Nucleic acids:
- DNA
Proteins
- Antibodies
- Protein kinases
  - Receptor tyrosine kinases
- Transcription factors
  - Leucine zipper motif proteins
  - Nuclear receptors
- 14-3-3 proteins
- G protein-coupled receptors
- G protein βγ-subunit dimer
- Kinesin
- Triosephosphateisomerase (TIM)
- Alcohol dehydrogenase
- Factor XI
- Factor XIII
- Toll-like receptor
- Fibrinogen

Revision as of 02:42, 25 July 2006

Chemistry

Biochemistry

Examples

See also