Arr Genes from Arsenate-Reducing Low G+C Gram Positive Bacteria Bacillus selenitireducens strain MLS10 and Clostridium sp. strain OhILAs

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Ranganathan, Mrunalini
arrB gene; arsenic; Bacillus selenitireducens strain MLS10; Clostridium sp. strain OhILAs; respiratory arsenate reductase
article description
The gene encoding the small subunit of the respiratory arsenate reductase (arrB) from the haloalkaliphilic low G+C Gram positive bacterium Bacillus selenitireducens strain MLS-10 was amplified by PCR, cloned and sequenced. The amplicon was larger (~ 1.2 kb) than predicted indicating that the degenerate reverse primer hybridized to a region further down stream. The amplicon contained all of arrB and the 5'end of another open reading frame. The arrB (693 bp) predicts a 26.3 kDa protein of 230 amino acids with a pI of 5.5 and four iron-sulfur binding domains. The protein shares a 50% identity and 66% similarity with ArrB from Shewanella sp. strain ANA-3. arrA and arrB were also successfully amplified from the freshwater low G+C Gram positive Clostridium sp. strain OhILAs using newly designed degenerate PCR primers. Interestingly, the Clostridial ArrA appears to be more closely related to Chrysiogenes arsenatis while its ArrB is more closely related to Shewanella sp. ANA-3. These results underscore the diversity in the arr operon.