Non-specific DNAases from the rumen bacterium Prevotella bryantii
2001
Accetto, T. | Avgustin, G. (University of Ljubljana, Domzale (Slovenia). Zootechnical Dept.)
Extracellular non-specific nucleases were observed in some strains belonging to the ruminal species of the genus Prevotella, mostly P. brevis and P. bryantii. The nuclease from P. bryantii appeared to be extracellular; it mediates the degradation of the supercoiled plasmid DNA via an open circle intermediate. The cleavage is not site specific although a preference for certain cleavage sites does seem exist. Our attempts to clone the wild-type P. bryantii B14 nuclease in E. coli strain ER 1992 that reports on the DNA damage sustained, were unsuccessful probably due to excessive intracellular nuclease activity that killed the cells bearing the gene for the nuclease. On the other hand, the nuclease from a related strain TC1-1, which has a less active enzyme of the same type, was successfully cloned.
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