The dominant PNM2(super -) mutation which eliminates the Psi factor of Saccharomyces cerevisiae is the result of a missense mutation in the SUP35 gene

Structural change caused by the mutation of PNM2 phenotype in S. cerevisiae transforms the affinity of SUP35 for PSi protein, leading to eventual elimination of Psi element. SUF12 mutation in the N-domain of SUP-35 results in frameshift suppression, which does not cause termination. The C-terminal domain imposes chain termination fidelity. The two terminals of SUP35 act in an antagonistic manner. Comparative levels of N- and C- terminal domains of SUP35p at the ribosome can modulate translation fidelity.