Table 1. Binding Affinities of the Cyclic DINNN-PepNats for the hSPSB2 Protein Determined by SPR.

entry	compound	structurea	KD (nM)b
1	D10-major	[I-FDINNNDap ]G	72 ± 16
2	D9-major	[I-FDINNNDab ]G	66 ± 8
3	D8-major	[I-FDINNNOrn ]G	282 ± 93
4	D1-major	[I-FDINNNK ]G	33 ± 15
5	D15-major	[I-fDINNNK ]G	>10000
6	D12-major	[I-LDINNNK ]G	10 ± 4
7	D12-minor	[I-LDINNNK ]G	127 ± 9
8	D2-major	[II-FDINNNK ]G	231 ± 43
9	D3-major	[III-FDINNNK ]G	309 ± 39
10	D17-major	[II-FDINNNDap ]G	1080 ± 76
11	D13-major	[I-VDINNNK ]G	15 ± 2
12	D13-minor	[I-VDINNNK ]G	78 ± 19
13	D18-major	[II-VDINNNK ]G	2.2 ± 0.3
14	D18-minor	[II-VDINNNK ]G	139 ± 76
15	D7-major	[VII-FDINNNK ]G	3.8 ± 0.5
16	D4-major	[IV-FDINNNK ]G	18 ± 7
17	D4-minor	[IV-FDINNNK ]G	>10000
18	22(53)	Ac-KEEKDINNNVKKT	7.1 ± 1.5
19	23(9)	Ac-DINNN	237 ± 34
20	24(9)	[CVDINNNC]	16 ± 4
21	25(66)	[WDINNNβA]	79 ± 10
22	26(14)	[VIII-DINNN]	175 ± 6
23	27	[IX-FDINNNK]	87 ± 2

^a[ ] indicates cyclic structure. Dap = diaminopropanoic acid; Dab = diaminobutanoic acid; Orn = ornithine. Lowercase letters indicate d-amino acids; bold residues are N-methylated.

^bK_D values are presented in nanomolar (nM) concentration as mean ± standard error of the mean (SEM) of three independent experiments using surface plasmon resonance (SPR) (for selected sensorgrams, see Supplementary Figure S8).