- Membrane topology
In biochemistry, the membrane topology of an transmembrane protein describes which portions of the amino-acid sequence of the protein lie within the plane of the surrounding lipid bilayer and which portions protrude into the watery environment on either side. More succinctly, the membrane topology describes which regions of the polypeptide chain span the membrane.
Because biochemists know the hydrophobicity of amino acids individually, the membrane topology of a protein (and indeed whether or not it is an integral membrane protein in the first place) often may be predicted accurately on the basis of a protein's sequence alone (which of course in turn may be predicted solely from the nucleotide sequence of a gene). Such predictions are most reliably based on the assumption that the lipid bilayer-spanning portions of a transmembrane protein will assume an alpha-helical secondary structure.
Since membrane topology is frequently the first available structural information about a protein after sequencing, integral membrane proteins are often classified or grouped according to this feature. In classifying proteins in this way, biologists look at the number of times the peptide chain is predicted to cross the membrane and may in fact name a class on this basis (e.g. "7TM receptors").
Membrane topology predictions also can be invaluable for developing antibodies, drugs or other reagents that will bind and/or affect the function of the protein.
Wikimedia Foundation. 2010.
Look at other dictionaries:
Virulence-related outer membrane protein family — Virulence related OMP Identifiers Symbol Ail Lom Pfam PF06316 … Wikipedia
Complement membrane attack complex — A membrane attack complex attached to a pathogenic cell. The membrane attack complex (MAC) is typically formed on the surface of intruding pathogenic bacterial cells as a result of the activation of the alternative pathway of the complement… … Wikipedia
Bacterial outer membrane — Structure of gram negative cell envelope The bacterial outer membrane is found in Gram negative bacteria. Its composition is distinct from that of the cytoplasmic membrane among other things, the outer leaflet of the membrane includes a complex… … Wikipedia
MARCH6 — Membrane associated ring finger (C3HC4) 6, also known as MARCH6, is a human gene.cite web | title = Entrez Gene: MARCH6 membrane associated ring finger (C3HC4) 6| url = http://www.ncbi.nlm.nih.gov/sites/entrez?Db=gene Cmd=ShowDetailView… … Wikipedia
Magnesium transporter — This page links directly from the magnesium in biological systems page. Magnesium transporters are proteins that transport magnesium across the cell membrane. All forms of life require magnesium, yet the molecular mechanisms of Mg2+ uptake from… … Wikipedia
Magnesium transporters — This page links directly from the magnesium in biological systems page. All forms of life require magnesium, and yet the molecular mechanisms of Mg2+ uptake from the environment and the distribution (transport) of this vital element within the… … Wikipedia
Dopamine transporter — Solute carrier family 6 (neurotransmitter transporter, dopamine), member 3 Identifiers Symbols … Wikipedia
Transmembrane protein — A transmembrane protein is a protein that spans the entire biological membrane. Transmembrane proteins aggregate and precipitate in water. They require detergents or nonpolar solvents for extraction, although some of them (beta barrels) can be… … Wikipedia
List of biochemistry topics — This page aims to list articles on Wikipedia that are related to biochemistry. This is so that those interested in the subject can monitor changes to the pages by clicking on .This list is not necessarily complete or up to date if you see an… … Wikipedia
Myelin proteolipid protein — (PLP or lipophilin) Identifiers Symbol Myelin PLP Pfam PF01275 InterPro … Wikipedia