Table 2.

Protein-dependent annealing and strand displacement rate constants and melting temperatures of RNAs in the absence and presence of protein Annealing rates k_ann of all RNA substrates in the absence of protein were between 0.005 and 0.008 s⁻¹

Protein	RNA	Annealing and strand displacement assay		UV melting analysis
		+ Protein		RNA only	+ Protein
		kann [s−1]	kSD [s−1]	Tm [°C]	Tm [°C]
Hfqa	JM1	0.028 ± 0.004	0.028 ± 0.004	44.7 ± 0.3	36.6 ± 3.6
	JM1h	0.031 ± 0.004	0.027 ± 0.006	n.d.	n.d.
	JM2	0.033 ± 0.008	0.024 ± 0.004	52.5 ± 0.4	50.9 ± 0.7
	JM2h	0.029 ± 0.007	0.027 ± 0.002	n.d.	n.d.
	JM3	0.026 ± 0.006	No SD	56.2 ± 0.2	56.6 ± 0.2
	JM3h	0.030 ± 0.005	0.024 ± 0.003	n.d.	n.d.
	JM4	0.032 ± 0.006	No SD	64.8 ± 0.2	65.3 ± 0.3
	JM4h	0.033 ± 0.007	0.031 ± 0.009	65.0 ± 0.3b	64.4 ± 0.6b
	JM6	No ann acc	No SD	76.0 ± 0.1	76.4 ± 0.4
	JM6h	No ann acc	No SD	n.d.	n.d.
Tat(44-61)c	JM1	0.036 ± 0.096	No SD		n.d.
	21R	0.032 ± 0.004	No SD	58.3 ± 0.3	71.7 ± 0.3
Scr1	21R	0.022 ± 0.002	n.d.		68.4 ± 0.6
Scr2	21R	0.014 ± 0.003	n.d.		73.0 ± 0.4
Scr3	21R	0.016 ± 0.003	n.d.		69.6 ± 0.1

Strand displacement was not measureable in the absence of protein. Values are means ± standard deviations of at least three measurements.

No ann acc, no acceleration of annealing; No SD, no strand displacement; n.d., not determined.

^a100 nM Hfq (ann and SD assay), 750 nM Hfq (UV melting).

^bMelting transition of the 21 base-pair long helix.

^c1 µM Tat(44-61) (ann and SD assay with JM1), 300 nM Tat(44-61) and scr1-3 (ann and SD assay with 21R), 2 µM Tat(44-61) and scr1-3 (UV melting).