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| | === Arsenate Reductase === | | === Arsenate Reductase === |
| − | Prokaryotes and eukaryotes use arsenate reductases of distinct folds. E. coli uses ArsC within ars operon located either on plasmids and chromosome. The ArsC belongs to [[Superfamily_Cys-based_III|Superfamily Cys-based III], the same as [[Phosphatase_Family_LMWPTP|LMWPTP]] and [[Phosphatase_Family_SSU72|SSU72]]. | + | Prokaryotes and eukaryotes use arsenate reductases of distinct folds. E. coli uses ArsC, which belongs to [[Superfamily_Cys-based_III|Superfamily Cys-based III]], the same as [[Phosphatase_Family_LMWPTP|LMWPTP]] and [[Phosphatase_Family_SSU72|SSU72]]. In eukaryotes, particularly fungi, plants and protists, ACR2 exhibit arsenate reductase activity <cite>yeo09</cite> |
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| − | Arsenical resistance in bacteria is conferred by the operons located either on plasmids or on chromosomes.1 The conjugative R-factor R773 isolated from Escherichia coli contains one such operon responsible for the antimonite, arsenite, and arsenate resistance.2, 3 Among the five genes of this ars operon, the ArsC protein exhibited arsenate reductase activity by catalyzing the conversion of arsenate to arsenite, which is then excreted from the cells.4 Another ars operon, containing only the arsR, arsB, and arsC genes, was also identified on E. coli chromosome.5, 6 The sequences homologous to the ars operon are ubiquitous in enterobacterial species,7 indicating that the chromosomal ars operon plays an important role in prokaryotes.
| + | === Reference === |
| − | | + | <biblio> |
| − | Compared with extensive studies carried out on bacterial systems, considerably less work has been done on the eukaryotic counterparts. In Saccharomyces cerevisiae, a budding yeast, a cluster of three novel genes ACR1, ACR2, and ACR3 have been found to confer resistance to arsenic compounds.7 The hypothetical product of the ACR1 gene is similar to the transcriptional regulatory proteins and that of the ACR3 gene is a transmembrane protein. The ACR2 gene encodes a polypeptide of 130 amino acid residues with a predicted molecular mass of 14.9 kDa. The presence of the ACR2 gene is indispensable for arsenate but not for arsenite resistance.7 Its gene product overexpressed in E. coli was shown to exhibit arsenate reductase activity and complement the arsenate-sensitive phenotype of an arsC deletion in E. coli.8, 9
| + | #yeo09 pmid=19382206 |
| | + | </biblio> |
Revision as of 15:28, 27 May 2014
Phosphatase Classification: Superfamily Cys-based II: Family CDC25: Subfamily Acr2
Arsenate Reductase
Prokaryotes and eukaryotes use arsenate reductases of distinct folds. E. coli uses ArsC, which belongs to Superfamily Cys-based III, the same as LMWPTP and SSU72. In eukaryotes, particularly fungi, plants and protists, ACR2 exhibit arsenate reductase activity [1]
Reference
- Yeo HK and Lee JY. Crystal structure of Saccharomyces cerevisiae Ygr203w, a homolog of single-domain rhodanese and Cdc25 phosphatase catalytic domain. Proteins. 2009 Aug 1;76(2):520-4. DOI:10.1002/prot.22420 | PubMed ID:19382206 | HubMed [yeo09]
