SuppressorssuaC 109 andsuaA 101 ofAspergillus nidulans alter the ribosomal phenotypein vitro

A new homologous, cell-free system for protein synthesis has been devised for use with ribosomes and elongation factors fromAspergillus nidulans. Ribosome preparations from strains with either the suaAlO1 orsuaCl09 mutations have a higher misreading ratio (non-cognate:cognate amino acid incorporation) in the presence of hygromycin than controls. They can be classed as fidelity mutants. These results also prove that the mutations must be in genes coding for ribosomal proteins or enzymes which modify ribosomal proteins post-translationally. Alternatively, the genes could code for translation factors.