Table 2. Signal Peptide K_d values and Energy Transfer efficiencies measured with signal peptides bound.

FRET pair	With SP22a		With SP41b
	EFRETc	Kd (μM)	EFRETa	Kd (μM)
340AF488-340AF568	0.64 ± 0.06	1.1 ± 0.4	0.23 ± 0.02	6.2 ± 4.3
458AF488-458AF568	0.45 ± 0.05	3.0 ± 1.7	0.45 ± 0.05	4.8 ± 0.6
506AF568-506AF647	0.67 ± 0.07	1.5 ± 0.7	0.69 ± 0.07	6.3 ± 1.0
696AF568-696AF647	0.42 ± 0.04	2.5 ± 0.2	0.41 ± 0.04	7.5 ± 1.3

^aA 22 residue peptide labeled with IAN at residue 22.

^bA 41 residue peptide labeled with IAN at position 2.

^cFRET efficiency (E_FRET) was measured as described in Table 1.