Table 1.

Characteristics of mutants that display an impaired growth phenotype

Mutant	Growth phenotype	Relative quantity of immunoprecipitated			Photolabeling of Ost1p	Relative labeling of Ost1p	OT activity
		Ost1p	Wbp1p	Swp1p
64-66AAA (30°C)	Normal	0.761	0.773	0.498	ND	ND	1.051
64-66AAA (37°C)	t.s.	0.617	0.508	0.161	ND	ND	0.305
324-326AAA	Lethal	1.000	0	0	0	0	ND
327-329AAA	Lethal	1.026	0	0	0	0	ND
330-333AAAA	Lethal	0.923	0	0	0	0	ND
Control	Normal	1.000	1.000	1.000	1.000	1.000	1.000
D306A (25°C)	t.s.	1.431	0.251	0.317	1.264	0.883	0.649
D306A (30°C)	t.s.	1.196	0.198	0.238	1.043	0.872	0.505
D306K	Lethal	0.563	0	0	0	0	ND
R326A (30°C)	Normal	1.354	0.783	0.860	1.135	0.838	0.826
R326A (37°C)	t.s.	1.402	0.727	0.969	0.901	0.643	0.366
Control	Normal	1.000	1.000	1.000	1.000	1.000	1.000

^*Growth phenotype was determined by 5-fluroorotic acid selection. t.s., temperature sensitive.

^† Relative quantity of immunoprecipitated Ost1p, Wbp1p, and Swp1p was determined by mild detergent immunoprecipitation followed by Western blot analysis. Quantitation was performed as described in Materials and Methods.

^‡ Photolabeling of Ost1p was performed as described in Materials and Methods and quantitation was based on densitometry of the autoradiograms. ND, not determined.

^§ Relative labeling of Ost1p was determined by dividing the amount of photolabeled Ost1p by the relative quantity of immunoprecipitated ost1p. ND, not determined.

^¶ OT activity was carried out as described in Roos et al. (25). ND, not determined.