Table 1. Spontaneous [Het-s] prion formation rate for alanine mutants of HET-s.

Strain	[Het-s]/total tested	% of prion formation	p-value (significance of difference to wt)**
WT	13/600	2.1%	-
F286A	0*	n.a
W287A	0*	n.a
R234A R274A	0*	n.a
N226A	3/500	0.6%	<0.05
Q240A	1/400	0.3%	<0.02
E272A	15/400	3.7%	n.s.
K284A	0/700	0	<0.0001
D288A	21/500	4.2%	<0.05
E234A R236A E265A	6/500	1.2%	n.s.
T233A S273A	24/500	4.8%	<0.02

*these mutants are unable to propagate [Het-s] even after infection by wt [Het-s].

**p-value is calculated in a two-tailed Fisher's test, n.s. non significant.