Table 1.

Synthetic foldon variants

Foldon variant		X-ray	Fold *
	Wild-type	no	yes
FV-1	[ΔGly1, Nal2, d-Ala10, Hot17═Tap18]	1.06 Å	yes
FV-2	[d-Ala10, d-Phe17]	0.98 Å	yes
FV-3	[d-Ala10, Hot17═Tap18]	1.50 Å	yes
FV-4	[d-Ala10]	no	yes
FV-5	[d-Ala10, d-Phe17, Pro18]	no	yes
FV-6	[Hot17═Tap18]	no	yes
FV-7	[d-Ala10, Btd17,18]	no	yes
FV-8	[Glu9, Hot17═Tap18]	no	no
FV-9	[Hot6═Tap7, d-Ala10, Hot17═Tap18]	no	no
FV-10	[d-Ala10, Hot17═Tap18, Hot23═Tap24]	no	no
FV-11	[d-Ala10, Hot17═Tap18,Hot25═Tap26]	no	no

¹H NMR spectra are shown in SI Text.

^*Determined by ¹H NMR.