A new transfer RNA fragment reaction: Tp psi pCpGp bound to a ribosome-messenger RNA complex induces the synthesis of guanosine tetra- and pentaphosphates.

The tetranucleotide TpPsipCpGp, when bound to Escherichia coli 50S ribosomal subunits, can replace intact tRNA in the stringent factor-directed synthesis of guanosine tetra- and pentaphosphates. The TpPsipCpGp-dependent fragment reaction has a strict requirement for the 50S and 30S ribosomal subunits and synthetic or natural messenger RNA.