Table 1.

Summary of the properties of the designed PLoop proteins

		General properties			Structural properties			Binding properties
PLoop	Ideal fold	MW (kDa)	Symmetry (%)	pI	Oligomerization	CD	Well-resolved NMR	ELISA	SPR	MST
A-PLoop	II	11.12	50.9	9.5	d/m	β/α	−	+	+	+
B-PLoop	II	11.24	43.4	8.0	d/m	β/α	−	+	+	+
C-PLoop	II	11.13	38.2	9.7	d/m	β/α	+	−	+	ND
D-PLoop	II	11.22	42.9	9.7	d/m	β/α	−	+	+	ND
E-PLoop	II	10.82	50.0	4.4	m	β/α	−	+	+	ND
F-PLoop	IV	12.35	30.4	4.6	m	β/α + random coil	−	−	ND	ND
3N3Z (15)	II	10.23	28.3	9.2	m	β/α	+	−	−	−
2LVB (15)	IV	11.58	17.5	6.6	m	β/α	+	−	ND	ND

The second column shows the ideal fold used as a scaffold (15); the third, fourth, and fifth columns indicate the MW (excluding the His-tag), internal sequence symmetry, and the theoretical isoelectric point. The oligomerization state was determined by native MS and SDS/PAGE (d, dimer; m, monomer). Binding properties: ELISA detected binding of the PLoop designs to immobilized ssDNA via anti–His-tag antibodies; MST, microscale thermofluoresis with soluble fluorescently labeled ssDNA; ND, not determined; SPR, surface plasmon resonance detection of binding to immobilized ssDNA or RNA oligos.