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phosphate/phosphite/phosphonate ABC transporter, periplasmic binding protein Phosphonates are a varied class of phosphorus-containing organic compound in which a direct C-P bond is found, rather than a C-O-P linkage of the phosphorus through an oxygen atom. They may be toxic but also may be used as sources of phosphorus and energy by various bacteria. Phosphonate utilization systems typically are encoded in 14 or more genes, including a three gene ABC transporter. This family includes the periplasmic binding protein component of ABC transporters for phosphonates as well as other, related binding components for closely related substances such as phosphate and phosphite. A number of members of this family are found in genomic contexts with components of selenium metabolic processes suggestive of a role in selenate or other selenium-compound transport. A subset of this model in which nearly all members exhibit genomic context with elements of phosphonate metabolism, particularly the C-P lyase system (GenProp0232) has been built (TIGR03431) as an equivalog. Nevertheless, there are members of this subfamily (TIGR01098) which show up sporadically on a phylogenetic tree that also show phosphonate context and are most likely competent to transport phosphonates. [Transport and binding proteins, Anions]
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