TABLE 1.

Effects of αSer-347 and α Gly-351 mutation on cell growth and ATPase activity

Mutationa	Growth on succinateb	Growth yield in limiting glucose	ATPase activityc
		%	μmol/min/mg
Wild type	++++	100	28
Null	–	46	0
βY331W	++++	95	26
αS347Q	±	55	0.20
αS347A	+	65	2.18
αG351Q	±	54	0.25

^aWild type, pBWU13.4/DK8; Null, pUC118/DK8, αS347Q/DK8, αG351Q/DK8, and αS347A/AN888. Both αS347Q and αG351Q mutants were expressed with the βY331W mutation also present, which does not significantly affect growth. The data are the means of four to six experiments each

^bGrowth on succinate plates after 3 days estimated by eye. ++++, heavy growth; +, partial growth; ±, very light growth; –, no growth

^cATPase activity was measured at 37°C and expressed as μmol of ATP hydrolyzed/min/mg of membrane protein. Each individual experimental point is itself the mean of duplicate assay tubes. The data are derived from two separate membrane preparations. The results from separate membrane preparations were in excellent agreement within ± 10%