Reading-frame shift in Saccharomyces glucoamylases restores catalytic base, extends sequence and improves alignment with other glucoamylases. 
A recent article [Coutinho and Reilly (1994) Protein Engng, 7, 749-760] presented the alignment of 14 glucoamylases by hydrophobic cluster analysis.  The catalytic bases of two of these glucoamylases, from Saccharomyces cerevisiae and Saccharomyces diastaticus, were not conserved, opening the possibility of a reading-frame shift error in a segment coding for amino acids near the apparent C-termini of the mature proteins.  Indeed, an addition of one nucleotide restores the catalytic base, extends the sequence by 39 residues and greatly improves the amino acid alignment in this region.