Table 1. Effects of mutations in PaExoY or VnExoY on toxicity in S. cerevisiae and in vitro activity.

Construct			Glucose (repressed)	Raffinose (background induction)	Galactose (highly induced)	In vitro activity [%]
vector		1	++	++	++	n.a.
PaExoY	wt	2	++	+	-	100
	K81M	3	++	++	+	0.01–0. 1
	K88I	4	++	++	-	n.t.
	K81M/K88I	5	++	++	++	n.d.
VnExoY	wt	6	++	+	-	100
	K117M	7	++	++	++	0.01–0. 1
	K124I	8	++	++	-	n.t.
	K117M/K124I	9	++	++	++	0.0005–0.005

S. cerevisiae MH272-3fα cells carrying a vector control (YEpGal555) or expressing the indicated proteins were grown on minimal agar plates at 30°C. Cell suspensions were normalized to an OD600 of 1.0 and serial dilutions (5-fold) were applied as 3 μl drops on agar plates containing 2% galactose (for high induction of P_Gal), 2% raffinose (background induction levels of P_Gal) or 2% glucose (for repression of P_Gal).

++: unaffected growth comparable to the vector control

+: intermediate growth

-: absence of growth

wt: wild type; n.a.: not applicable; n.d.: non detectable; n.t.: not tested. Original data are shown in S2 Fig.