Genetic determinants involved in Cr(VI) resistance IN Streptomyces sp. MC1

POLTI, MARTA ALEJANDRA; ATJIÁN, MARIANA CRISTINA; AMOROSO, MARÍA JULIA; ABATE; CARLOS MAURICIO

Tucumán

Congreso; XLV Reunión Anual de la Sociedad Argentina de Investigación en Bioquímica y Biología Molecular; 2009

SAIB

Biological transformation of Cr(VI) to Cr(III) provide environmentally friendly approach to remediation. Streptomyces sp. MC1 showed ability to reduce Cr(VI). Our aim was the evaluation of genetic determinants involved in this mechanism. Streptomyces sp. MC1 was screened for of plasmids by alkaline lysis and pulsed field gel electrophoresis. Chromate reductase gene was investigated, a pair of primers was designed using sequences of database, and used in PCR reactions. The amplicon was sequenced and compared with the databases. Phylogenetic trees were plotted. The techniques used did not allow plasmid isolation, however an amplicon of 222 bp was obtained. It showed similarity to proteins of aldehyde-dehydrogenase NAD-dependent family. Also, it showed similarity with actinomycetes proteins: putative aldehydedehydrogenases, ferredoxin reductase and proteins involved in heavy metals resistance. The amplicon translated sequence showed a 23.7% of similarity with the chromate reductase of T. scotoductus LTD-01. It is remarkable that the published chromate reductase protean sequences show a average similarity of only 27.3%. This putative chromate reductase gene was localized at chromosomal level. A fragment amplified from Streptomyces sp. MC1 was related to FMN oxidoreductases, suggesting that Cr(VI) resistance and reduction by Streptomyces sp. MC1 could be related to this protein family.