LOCALIZATION OF BETAINE HOMOCYSTEINE METHYLTRANSFERASE (BHMT) GENE IN Pseudomonas aeruginosa GENOME

JAVIER FERNANDO MARISCOTTI; ANDRES LIFFOURRENA; GLORIA LUCCHESI; ANGELA T. LISA

Tafí del Valle, Tucumán

Jornada; XVIII Jornadas Científicas de la Asociación de Biología de Tucumán; 2001

Asociación de Biología de Tucumán

P. aeruginosa is able to utilize betaine as sole carbon and nitrogen sources, and under hyperosmotic condition it is used as an osmoprotector agent. In view of the dual role of betaine in this bacterium we focussed the study of genetic organization of the BHMT, the enzyme responsible to convert betaine to dimethylglycine. A Tn5-751 mutant deficient in BHMT activity was obtained. The physical presence of the transposon in the chromosome was determined and the genomic fragment was cloned into a pBlueScript. The nucleotide sequence of the DNA insert shows an homology of 98% with the gene PA3081, of the genome sequence of P. aeruginosa PAO1, published in 2000 (www.pseudomonas.com). The determinations of SalI sites in the physical map of the cloned fragment allow us to localize the real Tn5-751 insertion site in the mutant chromosome. Then, it had occurred in PA3082, described as the gene that codes a hypothetical protein. By Blastp search of Gene Bank revealed that this protein shared homology to transferases. The most striking finding of this work is the different localization of genes involved in osmoprotection and in the DMG synthesis. Supported by SECyT - UNRC and Agencia Córdoba Ciencia.