TABLE 4.

Effect of point mutants in Hot₁₂θ and θ₁₁Hot chimeric proteins on the mutability of dnaQ49, dnaQ923, and dnaQ930 mutants^a

Proteinb	No. of Rifr mutants per 106 cells
	dnaQ49		dnaQ923	dnaQ930
	32°C	35°C
None (ΔholE)	65	55	27	0.33
θ	0.69	13	0.33	0.29
Hot	0.4	2.0	0.30	13
Hot12θ	0.72	12	2.4	44
Hot12θ (Y2Η)	0.5	34	37	50
Hot12θ (Α7Τ)	12	55	0.42	0.59
Hot12θ (N17H)	0.66	20	38	40
Hot12θ (W51C)	71	27	28	3.2
θ11Hot	0.52	1.7	0.11	1.4
θ11Hot (D9Y)	0.78	8.8	0.17	0.96
θ11Hot (V17I)	0.39		0.12	0.64
θ11Hot (F53S)	63	92	7.5	0.87

^aResults are the averages of two or three determinations. The dnaQ49 experiments were performed at 32° and 35°C; the dnaQ923 and dnaQ930 experiments were performed at 30°C.

^bAmino acid numbers (in parentheses) refer to the original residue numbers in θ or Hot.