. Author manuscript; available in PMC: 2021 Jul 13.

Published in final edited form as: J Biol Chem. 2007 Dec 28;283(9):5567–76. doi: 10.1074/jbc.M708620200

Table 3. ATPase activities ofthree E. coli DEAD box proteins, and site-directed variants in the presence and absence of RNA and RNase E-(696–762).

Protein	Activity without RNA^a	Activity with RNA^a
WT RhlB	≤0.5^b	≤0.5^b
WT RhlE	2.9 (0.8)	32.5 (7.1)
WT SrmB	9.3 (0.7)	34.1(2.3)
H320D RhlB	ND^c	ND^c
D310H RhlE	7.6 (1.1)	37.5 (4.0)
D313H SrmB	10.4 (2.3)	36.1 (3.5)
WT RhlB/RNase E-(696–762)^d	≤0.5^b	5.2 (0.5)
RhlBΔ1–397/RNase E-(696–762)^d	≤0.5^b	≤0.5^b
H320D RhlB/RNase E-(696–762)^d	ND^c	ND^c
S381A RhlB	≤0.5^b	≤0.5^b
S381A RhlB + RNase E-(696–762)^d	≤0.5^b	9.4 (2.2)
Y383A RhlB	ND^c	ND^c
Y383A RhlB + RNase E-(696–762)^e	ND^c	ND^c

^a The activities are expressed in moles of inorganic phosphate released per minute per mol of protein (mol/Pi/min/mol protein). The errors given in parentheses are the mean ± S.D.

^b An upper estimate of activity for proteins that display activity on theborderline for the sensitivity of the assay.

^c Activity not detectable after 10 min.

^d Co-expressed.

^e Added stoichiometrically.