Table 1.

Binding constants and specificity of selected and control peptides

Name	BoxBR (2AP-2), nM	GNRA (2AP-2), nM	P22 (2AP-2), nM
λ N (1-22)	1.0  ± 0.2	9.0  ± 0.7	41  ± 3
Selection 2
λ N (1-22; E14R15)	8.5  ± 2	800  ± 150*	580  ± 20
Selection 3
12-50 (1-22)	0.4  ± 0.1†	9  ± 2	14  ± 1
12-39 (1-22)	0.5  ± 0.1†	6.5  ± 0.7	8.4  ± 0.8
11-10 (1-22)	1.9  ± 0.5†	93  ± 9	140  ± 10
11-36 (1-22)	3.0  ± 0.2†	288  ± 7	246  ± 7
12-47 (1-22)	3.4  ± 0.1	81  ± 2	60  ± 3
Controls
λ N (1-11)	1,290  ± 20	19,000  ± 800	63,000  ± 7,200
λ N (1-15; E14R15)	303  ± 8	7,500  ± 300	12,300  ± 200
11-36 (1-22) scrambled	210  ± 25	3,400  ± 200	10,700  ± 200
12-47 (1-22) scrambled	140  ± 12	2,000  ± 80	5,200  ± 100

Binding constants were determined by fluorescence titration at 20°C, 50 mM KOAc/20 mM Tris⋅Oac, pH 7.5. All peptides contain a free amino and carboxyl terminus. λ N (1-11), λ N (1-15, E₁₄R₁₅), 11-36 (1-22) scrambled, and 12-47 (1-22) scrambled contain a C-terminal GY sequence to facilitate quantitation. 2AP-2 denotes a 2′-methoxy 2-aminopurine residue inserted at the second loop position. Error estimates indicate the precision of individual fits. Data for ERV from selection 2 indicates the binding is similar to λ N (1-22, E₁₄R₁₅; unpublished observation). 

^*Contains high uncertainty due to a small fluorescence change upon peptide addition. 

^† Indicates values determined by extrapolation from higher salt.