RESUMO
The 6645-bp mercury resistance transposon of the chemolithotrophic bacterium Thiobacillus ferrooxidans was cloned and sequenced. This transposon, named Tn5037, belongs to the Tn21 branch of the Tn21 subgroup, many members of which have been isolated from clinical sources. Having the minimum set of the genes (merRTPA), the mercury resistance operon of Tn5037 is organized similarly to most of the Gram-negative bacteria mer operons and is closest to that of Thiobacillus 3.2. The operator-promoter region of the mer operon of Tn5037 also has the common (Tn21/Tn501-like) structure. However, its inverted, presumably MerR protein binding repeats in the operator/promoter element are two base pairs shorter than in Tn21/Tn501. In the merA region, this transposon shares 77.4, 79.1, 83.2 and 87.8% identical bases with Tn21, Tn501, T. ferrooxidance E-15, and Thiobacillus 3.2, respectively. No inducibility of the Tn5037 mer operon was detected in the in vivo experiments. The transposition system (terminal repeats plus gene tnpA) of Tn5037 was inactive in Escherichia coli K12, in contrast to its resolution system (res site plus gene tnpR). However, transposition of Tn5037 in this host was provided by the tnpA gene of Tn5036, a member of the Tn21 subgroup. Sequence analysis of the Tn5037 res site suggested its recombinant nature.
Assuntos
Elementos de DNA Transponíveis , Resistência Microbiana a Medicamentos/genética , Mercúrio/toxicidade , Thiobacillus/genética , Sequência de Bases , Clonagem Molecular , DNA Bacteriano , Dados de Sequência Molecular , Homologia de Sequência do Ácido NucleicoRESUMO
A program package "SAMSON" for the computer analysis of biopolymer primary structures is described. All possible modes of sequence investigation are considered. The programs for sequence comparison are described in some details. The general principles of a program package organisation and of its user interface are also mentioned. For more complete information see Vernoslov S.E. et al. "Program package "SAMSON" for the analysis of the polymer primary structures", parts 1 and 2, Poustchino, ONTI NCBI, 1989.
