Arsenite-antimonite transporters are
membrane transporter
A membrane transport protein is a membrane protein involved in the movement of ions, small molecules, and macromolecules, such as another protein, across a biological membrane. Transport proteins are integral transmembrane proteins; that is they e ...
s that pump
arsenite
In chemistry, an arsenite is a chemical compound containing an arsenic oxyanion where arsenic has oxidation state +3. Note that in fields that commonly deal with groundwater chemistry, arsenite is used generically to identify soluble AsIII anions ...
or
antimonite
In chemistry, antimonite refers to a salt of antimony(III), such as NaSb(OH)4 and NaSbO2 (meta-antimonite), which can be prepared by reacting alkali with antimony trioxide, Sb2O3.Egon Wiberg, Arnold Frederick Holleman (2001) ''Inorganic Chemistry' ...
out of a cell. Antimonite is the salt of antimony (Sb(III)) and has been found to significantly impact the toxicity of arsenite. The similar structure of As(III) and Sb(III) makes it plausible that certain transporters function in the efflux of both substrates. Arsenic efflux transporters exist in almost every organism and serve to remove this toxic compound from the cell.
Subfamilies
As of early 2016, there are at least three known families of proteins known to participate in arsenite and antimonite efflux.
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ArsB familyTC# 2.A.45
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ArsAB FamilyTC# 3.A.4
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Arsenical resistance-3 (ARC3) familyTC#2.A.59
The membrane transporter ArsB can function as a secondary carrier or as a primary active transporter, in which case ArsA, an ATPase, must be superimposed onto ArsB. Arsenite and antimonite can also be pumped out of the cell by members of the ARC3 family, a member of the
BART superfamily, which can participate in both secondary transport or primary active transport. Based on operon analyses, Arc3 homologues may similarly function either as secondary carriers or as primary active transporters. In the latter case
ATP hydrolysis
ATP hydrolysis is the catabolic reaction process by which chemical energy that has been stored in the high-energy phosphoanhydride bonds in adenosine triphosphate (ATP) is released after splitting these bonds, for example in muscles, by produ ...
again energizes transport.
See also
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Arsenic toxicity
Arsenic poisoning (or arsenicosis) is a medical condition that occurs due to elevated levels of arsenic in the body. If arsenic poisoning occurs over a brief period of time, symptoms may include vomiting, abdominal pain, encephalopathy, and wat ...
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Arsenite-transporting ATPase
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Solute carrier family
The solute carrier (SLC) group of membrane transport proteins include over 400 members organized into 66 families. Most members of the SLC group are located in the cell membrane. The SLC gene nomenclature system was originally proposed by the HUGO ...
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Active transport
In cellular biology, active transport is the movement of molecules or ions across a cell membrane from a region of lower concentration to a region of higher concentration—against the concentration gradient. Active transport requires cellula ...
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ATP-binding cassette transporter
The ABC transporters, ATP synthase (ATP)-binding cassette transporters are a transport system superfamily that is one of the largest and possibly one of the oldest gene family, gene families. It is represented in all extant taxon, extant Phyl ...
References
Protein families
Solute carrier family
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