Protein synthesis in the thermoacidophilic archaeon Sulfolobus solfataricus (Ss) was inhibited by polynucleotide: adenosine glycosylase activity of some type 1 ribosome-inactivating proteins (RIP). The target of RIP was S. solfataricus rRNA that was depurinated thus producing inactive ribosomes. The amount of RIP required to half-inactivated Ss-ribosomes was comparable to that needed for eubacterial ribosomes, but two orders of magnitude higher than that required for mammalian ribosomes. In addition, RIP treated Ss-ribosomes were also less efficient in stimulating the ribosome dependent GTPase activity of the S. solfataricus elongation factor 2 (SsEF-2) thus suggesting that the inhibition of protein synthesis was probably due to the lack of the interaction between depurinated Ss-ribosomes and SsEF-2. Since SsEF-2 protects Ss-ribosomes against RIP activity it can be hypothesised that also on Ss-ribosomes the sites of interaction for the translocation factor 2 and the RIP are topographically close.

The effect of ribosome-inactivating proteins on the ribosome from the hyperthermophilic archaeon Sulfolobus solfataricus

MASULLO, Mariorosario;
1998

Abstract

Protein synthesis in the thermoacidophilic archaeon Sulfolobus solfataricus (Ss) was inhibited by polynucleotide: adenosine glycosylase activity of some type 1 ribosome-inactivating proteins (RIP). The target of RIP was S. solfataricus rRNA that was depurinated thus producing inactive ribosomes. The amount of RIP required to half-inactivated Ss-ribosomes was comparable to that needed for eubacterial ribosomes, but two orders of magnitude higher than that required for mammalian ribosomes. In addition, RIP treated Ss-ribosomes were also less efficient in stimulating the ribosome dependent GTPase activity of the S. solfataricus elongation factor 2 (SsEF-2) thus suggesting that the inhibition of protein synthesis was probably due to the lack of the interaction between depurinated Ss-ribosomes and SsEF-2. Since SsEF-2 protects Ss-ribosomes against RIP activity it can be hypothesised that also on Ss-ribosomes the sites of interaction for the translocation factor 2 and the RIP are topographically close.
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Utilizza questo identificativo per citare o creare un link a questo documento: http://hdl.handle.net/11367/28844
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