Table III.

NBD fluorescence lifetimes of free and membrane-bound RNCsa

NBD-labeled speciesb Membranes Probe-PTC separationc NBD location τ1 f1d τ2 f2d χ2 <τ>e 
    ns  ns   ns 
pPL90 + 15 Tunnel 0.7 ± 0.1 0.90 8.8 ± 0.2 0.10 4 1.5 ± 0.1 
111p90 + 15 Tunnel 2.1 ± 0.2 0.61 8.6 ± 0.2 0.39 2 4.6 ± 0.2 
111p130 + 55 Translocon 2.3 ± 0.4 0.61 7.9 ± 0.5 0.39 1 4.5 ± 0.4 
111p130 − 55 Solvent 0.8 ± 0.1 0.75 9.2 ± 0.1 0.25 4 2.9 ± 0.1 
2TML12K2122 + 18 Tunnel 2.5 ± 0.6 0.50 7.8 ± 0.3 0.50 3 5.2 ± 0.5 
2TML12K2130 + 26 Tunnel 2.8 ± 0.1 0.61 9.4 ± 0.1 0.39 7 5.4 ± 0.1 
2TML12K2148 + 44 Translocon 2.6 ± 0.2 0.55 9.5 ± 0.2 0.45 3 5.7 ± 0.2 
2TML12K2160 + 56 Translocon 2.4 ± 0.3 0.54 9.3 ± 0.3 0.46 4 5.6 ± 0.3 
2TML12K2180 − 76 Solvent 1.3 ± 0.3 0.65 8.0 ± 0.3 0.35 1 3.6 ± 0.3 
NBD-labeled speciesb Membranes Probe-PTC separationc NBD location τ1 f1d τ2 f2d χ2 <τ>e 
    ns  ns   ns 
pPL90 + 15 Tunnel 0.7 ± 0.1 0.90 8.8 ± 0.2 0.10 4 1.5 ± 0.1 
111p90 + 15 Tunnel 2.1 ± 0.2 0.61 8.6 ± 0.2 0.39 2 4.6 ± 0.2 
111p130 + 55 Translocon 2.3 ± 0.4 0.61 7.9 ± 0.5 0.39 1 4.5 ± 0.4 
111p130 − 55 Solvent 0.8 ± 0.1 0.75 9.2 ± 0.1 0.25 4 2.9 ± 0.1 
2TML12K2122 + 18 Tunnel 2.5 ± 0.6 0.50 7.8 ± 0.3 0.50 3 5.2 ± 0.5 
2TML12K2130 + 26 Tunnel 2.8 ± 0.1 0.61 9.4 ± 0.1 0.39 7 5.4 ± 0.1 
2TML12K2148 + 44 Translocon 2.6 ± 0.2 0.55 9.5 ± 0.2 0.45 3 5.7 ± 0.2 
2TML12K2160 + 56 Translocon 2.4 ± 0.3 0.54 9.3 ± 0.3 0.46 4 5.6 ± 0.3 
2TML12K2180 − 76 Solvent 1.3 ± 0.3 0.65 8.0 ± 0.3 0.35 1 3.6 ± 0.3 
a

For each RTC, data from three or more independent experiments were combined and analyzed together as described in Materials and methods.

b

NBD is located at residue 104 of 2TML12K2 in these experiments.

c

Nascent chain residues between nascent chain εNBD-Lys and the PTC.

d

Molar fraction.

e

Average lifetime from molar fractions.

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