CONICET | Buscador de Institutos y Recursos Humanos

High altitude Andean wetlands are characterized by extreme environmental conditions such as high UV radiation, elevated heavy metal content and salinity. Bacteria isolated from these environments evolved to survive in the mentioned extreme conditions. Acinetobacter strain Ver3 isolated from Verde Lake (4000 meters OS) displayed high UV tolerance and resistence to pro-oxidants as peroxide and superoxide propagators. Interestingly, total catalase activity in Ver3 cell-free extracts was shown to be fifteen times higher than those of control collection strains, being associated to one of two activity bands observed after non-denaturing electrophoresis. After a genome pyrosequencing strategy and annotation (http://rast.nmpdr.org), two genes were identified corresponding to hydroperoxidases (HP) types I and II. Sequence alignment comparisons display subtle structural differences, but the resulting phylogenetic trees showed a unique HPI group present in the Acinetobacter genus and three different HPII clusters. Design of adequate primers allow PCR molecular cloning and expression of the HPII recombinant enzyme in transformed Escherichia coli cells using pET28 vector. Non-denaturing gel electrophoresis followed by activity staining enable final identification of the gene responsible of the high catalase activity previously observed in the multiresistent Acinetobacter Ver3 isolate.