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Molecular cloning of rhodanese gene from soil metagenome of cold desert of North-West Himalayas: sequence and structural features of the rhodanese enzyme
- Bhat, Archana, Riyaz-Ul-Hassan, Syed, Srivastava, Nidhi, Johri, Sarojini
- 3 Biotech 2015 v.5 no.4 pp. 513-521
- Cyanobacterium (genus), Synechococcus, Wolinella succinogenes, active sites, cyanides, cysteine, genes, genomic libraries, metagenomics, microorganisms, models, molecular cloning, open reading frames, polypeptides, screening, sequence analysis, soil, thiosulfate sulfurtransferase, Himalayan region, India
- Rhodanese is a multifunctional, sulfur transferase that catalyzes the detoxification of cyanide by sulphuration in a double displacement (ping pong) mechanistic reaction. In the present study, small-insert metagenomic library from soil sample collected from Ladakh (3,000–3,600 m.a.s.l) in northwestern Himalayas, India was constructed. Function-driven screening of ~8,500 colonies led to the isolation of one esterase-positive clone (clone-est) harboring 2.43 kb insert. Sequence analysis of the insert identified two ORF’s, phosM encoding phosphoesterase and rodM encoding rhodanese. The 800 bp rodM gene encoded a polypeptide of 227 amino acids (RodM). The RodM showed maximum homology with the rhodanese-like protein from Cyanobacterium synechococcus species with a score identity of only 51 %. Putative 3D structure of RodM developed by homology modeling resembles to homodimeric protein of SUD sulfur transferase of Wolinella succinogenes with properly structured active-site cysteine (Cys) residue. Rhodanese has been reported from few culturable microorganisms.