title: A new arsenate reductase involved in arsenic detoxification in Anabaena sp. PCC7120.
abstract: In silico analysis followed by experimental validation leads us to propose that the predicted protein All0195 of Anabaena sp. PCC7120 showing enhanced expression under sodium arsenate (Na2HAsO4) stress belongs to the thioredoxin superfamily with structural similarity to bacterial arsenate reductase. The All0195 protein demonstrated C-X-TC-X-K, NTSG-X2-YR, and D-X2-L-X-KRP as functional motifs that show similarity to seven known bacterial arsenate reductase family protein homologs with Cys, Arg, and Pro as conserved residues. In view of physicochemical properties, such as aliphatic index, ratio of Glu + Lys to Gln + His, and secondary structure, it was evident that All0195 was also a thermostable protein. The predicted three-dimensional structure on molecular docking with arsenate oxyanion ([Formula: see text]) revealed its interaction with conserved Cys residue as also known for other bacterial arsenate reductase. In silico derived properties were experimentally attested by cloning and heterologous expression of all0195. Furthermore, this protein functionally complemented the arsenate reductase-deficient sodium arsenate-hypersensitive phenotype of Escherichia coli strainWC3110 (ΔarsC) and depicted arsenate reductase activity on purification. In view of the above properties, All0195 appears to be a new arsenate reductase involved in arsenic detoxification in Anabaena sp. PCC7120.
authors.affiliation: Molecular Biology Section, Laboratory of Algal Biology, Center of Advanced Study in Botany, Banaras Hindu University, Varanasi 221005, India.
authors.forename: Sarita
authors.initials: S
authors.lastname: Pandey
authors.forename: A K
authors.initials: AK
authors.lastname: Shrivastava
authors.forename: V K
authors.initials: VK
authors.lastname: Singh
authors.forename: R
authors.initials: R
authors.lastname: Rai
authors.forename: P K
authors.initials: PK
authors.lastname: Singh
authors.forename: S
authors.initials: S
authors.lastname: Rai
authors.forename: L C
authors.initials: LC
authors.lastname: Rai
mesh_terms: D020816:Amino Acid Motifs; D000595:Amino Acid Sequence; D017033:Anabaena / Q000201:enzymology* / Q000235:genetics; D053502:Arsenate Reductases / Q000737:chemistry / Q000235:genetics / Q000378:metabolism*; D001149:Arsenates / Q000633:toxicity*; D001426:Bacterial Proteins / Q000737:chemistry / Q000235:genetics / Q000378:metabolism*; D020134:Catalytic Domain; D017124:Conserved Sequence; D008958:Models, Molecular; D008969:Molecular Sequence Data; D009154:Mutation; D017434:Protein Structure, Tertiary
chemical_list: D001149:Arsenates; D001426:Bacterial Proteins; D053502:Arsenate Reductases