Table 1.

Sequences and properties of synthesized peptides.

Code	Sequencea	Predicted helical content%b	Predicted antigenicity (AD)c	Experimental helical content%d	% Inhibition of SARSCoV-2 replication at 10 μMe	SARSCoV-2 virus titer at 1 μM (PFU mL−1) on Calu-3f	IC50 (nM)g Calu-3	KDh (nM)
P1	STIEE QAKTF LDKFN HEAED LFYQS SL-NH2	6	0	7	9	–	–	–
P1scr	AHLFS YLTTK EEQDN DAIFL QEFSK ES-NH2	1	0	8	7	–	–	–
Ppen	IEE QAKTF LDKFN HEAED LFYQS-NH2	1	0	10	14	–	–	–
P2	SALEE QLKTF LDKFL HELED LLYQL SL-NH2	64	1	70	16	–	–	–
P3	SALEE QLKTF LDKFL HELED LLYQL AL-NH2	78	1	64	4	–	–	–
P4	Ac-SALEE QLKTF LDKFL HELED LLYQL AL-NH2	66	1	70	24	–	–	–
P5	SALEE QLKTF LDKFL HELED PLYQL AL-NH2	34	1	17	27	–	–	–
P6	SALEE QLKTF LDKFL HELED LLYQL ALAL-NH2	88	1	80	6,5	–	–	–
P7	SALEE QYKTF LDKFL HELED LLYQL ALAL-NH2	n.a.	n.a.	63	54	–	–	–
P8	SALEE QLKTF LDKFM HELED LLYQL AL-NH2	68	0	70	91	0	46	24 ± 11
P9	SALEE QYKTF LDKFM HELED LLYQL SL-NH2	n.a.	n.a.	53	93	0	53	0.09 ± 0.08
P10	SALEE QYKTF LDKFM HELED LLYQL AL-NH2	n.a.	n.a.	56	95	0	42	0.03 ± 0.01

^aThe homotyrosine residue is depicted with the underlined letter Y in peptides P7, P9, and P10.

^bPredicted helical content using Agadir program available at https://agadir.crg.es; n.a., not applicable (for hTyr containing sequences).

^cPredicted antigenicity calculated at http://imed.med.ucm.es/Tools/antigenic.pl; n.a., not applicable (for hTyr containing sequences).

^dExperimental helical content determined by circular dichroism (see Fig. 2).

^eMean percentage of inhibition on Vero-E6 cells of at least three independent experiments (see Fig. 3a and Supplementary Fig. 3).

^fMean viral titration on Calu-3 cells (see Fig. 3d (Fig. 3b for Vero-E6 cells)).

^ggIC₅₀ determined on Calu-3 cells only for peptides able to inhibit SARSCoV-2 cell infection.

^hDissociation constants with SARS-Cov-2 RBD-SD1 measured by BLI for peptides with IC₅₀ in the nM range. K_D values are the mean of three independent determinations (P9 and P10).