Multi antimicrobial extrusion protein (MATE) also known as multidrug and toxin extrusion or multidrug and toxic compound extrusion is a family of protein

Protein

Proteins are biochemical compounds consisting of one or more polypeptides typically folded into a globular or fibrous form, facilitating a biological function. A polypeptide is a single linear polymer chain of amino acids bonded together by peptide bonds between the carboxyl and amino groups of...

s which function as drug/sodium or proton antiporter

Antiporter

An antiporter is an integral membrane protein involved in secondary active transport of two or more different molecules or ions across a phospholipid membrane such as the plasma membrane in opposite directions.In secondary active transport, one species of solute moves along its electrochemical...

s.

Function

The MATE proteins in bacteria

Bacteria

Bacteria are a large domain of prokaryotic microorganisms. Typically a few micrometres in length, bacteria have a wide range of shapes, ranging from spheres to rods and spirals...

, archaea

Archaea

The Archaea are a group of single-celled microorganisms. A single individual or species from this domain is called an archaeon...

 and eukaryote

Eukaryote

A eukaryote is an organism whose cells contain complex structures enclosed within membranes. Eukaryotes may more formally be referred to as the taxon Eukarya or Eukaryota. The defining membrane-bound structure that sets eukaryotic cells apart from prokaryotic cells is the nucleus, or nuclear...

s function as fundamental transporters of metabolic and xenobiotic organic cations.

Structure

These proteins are predicted to have 12 alpha-helical

Alpha helix

A common motif in the secondary structure of proteins, the alpha helix is a right-handed coiled or spiral conformation, in which every backbone N-H group donates a hydrogen bond to the backbone C=O group of the amino acid four residues earlier...

 transmembrane

Transmembrane protein

A transmembrane protein is a protein that goes from one side of a membrane through to the other side of the membrane. Many TPs function as gateways or "loading docks" to deny or permit the transport of specific substances across the biological membrane, to get into the cell, or out of the cell as...

 regions, some of the animal proteins may have an additional C-terminal helix. The X-ray structure of the NorM was determined to 3.65 Å, revealing an outward-facing conformation with two portals open to the outer leaflet of the membrane and a unique topology of the predicted 12 transmembrane helices distinct from any other known multidrug resistance transporter.

Discovery

The multidrug efflux transporter

Transporter

Transporter may refer to:* Transporter , types of vehicles designed to transport items* Volkswagen Transporter, a model of van- Film and television :...

 NorM from V. parahaemolyticus

Vibrio parahaemolyticus

Vibrio parahaemolyticus is a curved, rod-shaped, Gram-negative bacterium found in brackish saltwater, which, when ingested, causes gastrointestinal illness in humans. V. parahaemolyticus is oxidase positive, facultatively aerobic, and does not form spores...

which mediates resistance to multiple antimicrobial agents (norfloxacin

Norfloxacin

Norfloxacin is a synthetic chemotherapeutic antibacterial agent occasionally used to treat common as well as complicated urinary tract infections. It is sold under various brand names with the most common being Noroxin. In form of ophthalmic solutions it is known as Chibroxin...

, kanamycin

Kanamycin

Kanamycin sulfate is an aminoglycoside antibiotic, available in oral, intravenous, and intramuscular forms, and used to treat a wide variety of infections. Kanamycin is isolated from Streptomyces kanamyceticus.-Mechanism:...

, ethidium bromide

Ethidium bromide

Ethidium bromide is an intercalating agent commonly used as a fluorescent tag in molecular biology laboratories for techniques such as agarose gel electrophoresis. It is commonly abbreviated as "EtBr", which is also an abbreviation for bromoethane...

 etc) and its homologue from E. coli

Escherichia coli

Escherichia coli is a Gram-negative, rod-shaped bacterium that is commonly found in the lower intestine of warm-blooded organisms . Most E. coli strains are harmless, but some serotypes can cause serious food poisoning in humans, and are occasionally responsible for product recalls...

were identified in 1998. NorM seems to function as drug/sodium antiporter

Antiporter

An antiporter is an integral membrane protein involved in secondary active transport of two or more different molecules or ions across a phospholipid membrane such as the plasma membrane in opposite directions.In secondary active transport, one species of solute moves along its electrochemical...

 which is the first example of Na⁺-coupled multidrug efflux transporter discovered. NorM is a prototype of a new transporter

Transporter

Transporter may refer to:* Transporter , types of vehicles designed to transport items* Volkswagen Transporter, a model of van- Film and television :...

family and Brown et al. named it the multidrug and toxic compound extrusion family. NorM is nicknamed "Last of the multidrug transporters." because it is the last multidrug transporter discovered functionaly as well as structually