Table 1. Model parameters used in simulations.

	Symbol	value	unit	Comment
First-order rate constant for ADP-ribosylation	k cat	0.0045	s−1	assumed1
Total EF2 in the system	[EF2]t	0.6	µM/cell	[36]
Total ribosomes engaging in mRNA translation	[R]t	0.5	µM/cell	[37] 2
EF1-initiated peptidyl insertion rate constant	k 0,max	4	s−1	[38]
Association rate constant between E GTP and R •	k 1	96	µM−1 s−1	[8], [9] 3
Dissociation rate constant for		0.3	s−1	assumed
Translocation rate constant for	k 2	35	s−1	[8], [9]
EF2•GDP release rate constant for	k 3	5	s−1	[8], [9] 4
GTP exchange rate constant for E GDP	k 4	12.8	µM s−1	[39]
EF2•GDP dissociation constant	K d,GDP	0.5	µM	[24]
EF2•GTP dissociation constant	K d,GTP	2.68	µM	[24]
Free GTP concentration	[GTP]	400	µM	[35]
Free GDP concentration	[GDP]	40	µM	assumed5
Polysomal density	m	10	# ORF−1	assumed
Threshold for dead-end translocation block in f	f c	0.09		[17]
Basal fraction of translocation-active ribosomes		0.29		modeled
Basal stalling coefficient		0.14		modeled

The rate constant is set equal to k ₃ throughout the work, whereas , and may differ from their native counterparts.

¹Calculated from λ _cat [T], using λ _cat = 1.7×10⁹ M⁻¹ min⁻¹ [34] and [T] = 0.16 nM (equivalent to 250 toxin molecules in the cytosol of a cell, with a cell cytosol volume equal to 2.6 pL [35].

²Obtained by the ratio of [EF2]_t : [R]_t = 1.2∶ 1 [37] using the estimated [EF2]_t.

³Calculated as k ₁ = k _a k _GTP/(k _d+k _GTP) = 150*250/(140+250) = 96 s⁻¹.

⁴Taken as the rate constant for relocking [8], [9].

⁵Based on [GTP]:[GDP] = 10∶1 [32].