FIG. 5.

Eng2 catalytic activity is required for ascus endolysis. (A) Schematic representation of Eng2. The gray rectangle indicates the common region present in GH81 proteins that contains the putative catalytic domain of the protein (black rectangle). The white circle marks the position of the two perfectly conserved Glu residues, which have been proposed to act as putative nucleophiles (asterisks). E537 was mutated to Ala. (B) Quantification of ascospore release from the asci in sporulated cultures. At the indicated time intervals, the percentages of free ascospores were determined by light microscopy. At least 150 cells were counted for each time point. The crosses were OL176/OL177 (WT), OL759/OL773 (eng2Δ), OL759/OL773 carrying pJED12 (eng2Δ/peng2⁺), and OL759/OL773 carrying pJED13 [eng2Δ/peng2(E537A)].