Preparation, optimization and characterization of a polyphenylalanine synthetizing system from Agrobacterium tumefaciens.

A very active cell-free translation system was prepared from Agrobacterium tumefaciens, a bacterium broadly used to transfect plant cells to introduce foreign genes and one that produces tumours in plants. Once optimized for Mg2+, NH4+, high speed supernatant S 370, purified ribosomes and time, the system translates polyuridylic acid very efficiently. A. tumefaciens purified ribosomes were inhibited in vitro by several well-known translational inhibitors including some ribosome-inactivating proteins. Treatment of A. tumefaciens purified ribosomes with type 1-RIP crotin 2 lead to the depurination of the 23S rRNA which, upon treatment with acid aniline, released a diagnostic RNA fragment of about 235 nucleotides.