Table 1. Affinities of PDZ, PTB, FERM, SH2, and ATG8 domains as well as AP2 μ2 for the ACE2 C-terminal peptide as determined by FP.

Equilibrium dissociation constant (K_D) values of the tested domains for FITC-labeled ACE2 C-terminal peptides. Indicated errors are the errors of the mean (SEM); n = 3 replicates. N.B., no or low affinity (K_D >100 μM).

Peptide sequence	Name	Modification	KD ± SEM (μM)
ACE2796-805* FITC-QNTDDVQTSF-COO−	MAGI1 PDZ1	Unphos.	N.B.
	NHERF3 PDZ1		13.9 ± 0.3
	NHERF3 PDZ3		N.B.
	SCRIB PDZ1		N.B.
	SHANK1 PDZ		8.3 ± 0.2
	SNTA1 PDZ		N.B.
	SNX27 PDZ		4.7 ± 0.3
	TAX1BP3 PDZ		N.B.
ACE2787–798 FITC-SKGENNPGFQNT-NH2	DOK1 PTB	Unphos.	N.B.
	FRS2 PTB		N.B.
	IRS1 PTB		N.B.
	TLN1 PTB		N.B.
	TLN2 PTB		N.B.
	SNX17 FERM		(100)†
ACE2775–790 FITC-RSGENPYASIDISKGE-NH2	AP2 μ2	Unphos.	(60)†
		pTyr781	N.B.
		pSer783	(30)†
	FYN SH2	Unphos.	N.B.
		pTyr781	7.0 ± 0.5
		pSer783	N.B.
	NCK1 SH2	Unphos.	N.B.
		pTyr781	N.B.
		pSer783	N.B.
	LYN SH2	Unphos.	N.B.
		pTyr781	(60)
		pSer783	N.B.
	MAP1LC3A ATG8	Unphos.	N.B.
		pTyr781	N.B.
		pSer783	N.B.
	MAP1LC3B ATG8	Unphos.	N.B.
		pTyr781	N.B.
		pSer783	N.B.
	GABARAP ATG8	Unphos.	N.B.
		pTyr781	N.B.
		pSer783	N.B.
	GABARAPL2 ATG8	Unphos.	N.B.
		pTyr781	N.B.
		pSer783	N.B.

*MBP was tested as a control for binding (N.B.) due to the PDZ domains being MBP-tagged. †Values in brackets indicate estimated affinities due to incomplete saturation curves.