Poly -programmed cell-free systems

Information on archaeal translation is essentially based on poly(U)- and poly(UG)-programmed cell-free systems and on peptidyltransferase assay systems. Poly(U)-directed systems have been used to monitor the reconstruction of archaeal ribosomal subunits and the susceptibility of archaea to protein synthesis inhibitors. 

A Poly(U)-programmed cell-free system from H. cutirubrum requiring saturating salt concentrations was developed by Bayley and Griffiths [117] ten years before extreme halophiles were assigned to the newly discovered archaea. Poly(U)- and poly(UG)-directed systems using purified ribosomes and post-ribosomal supernatant fractions have been subsequently developed from most known archaea. 

Fig. 4. Kinetics of polyphenylalanine synthesis at different temperatures, and Arrhenius plots of poly(phe) synthesis in S. solfataricus and E. coli poly-U programmed cell-free systems. Rates of polyphenylalanine synthesis were calculated from the initial slopes of the incorporation kinetics at different temperatures [Cammarano, P, unpublished results].

Cell-free systems for methanogen ribosomes are based on the poly(U)- and poly(UG)-programmed system originally developed by Elhardt and Bock [121] for M vannielii. Aside from the tedious procedures involved in carrying out the initial cell fractionations under anaerobic conditions, the methanogen systems do not differ substantially from the classical E. coli cell-free system in their ionic requirements (10 mM Mg ", 10 mM and... 

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