Table 1.

Estimated occupancy of rrn operons in WT and Δrrn strains as a function of growth rate

Strain	Medium	Doubling time (min)	NrRNAP per cella	oriC copies per cell	rrn copies per cell	NrRNAP per rrn	RNAP occupancy of each rrnb
WT	M9Glu	47	397	2.9	17.5	23	32%
Δ5	M9Glu	57	238	2.5	4.8	50	69%
Δ6	M9Glu	73	122	2.2	2.0	61	85%
WT	RDM	36	805	3.7	22.0	37	51%
Δ5	RDM	46	420	2.9	5.6	75	104%
Δ6	RDM	51	320	2.7	2.5	128	178%

For the methods used to obtain the estimates for growth at 37°C, see the Materials and Methods.

^aNumber of RNAP molecules transcribing rrn operons in the different strains.

^b100% occupancy is defined as the RNAP occupancy at the maximum growth rate (72 rRNAPs/rrn). Note that this occupancy is substantially lower than the maximal physical occupancy (see also the Discussion).