Table 4.

Thermal stability and antigen-binding affinity of anti-HER2 variants are comparable to the parent molecules. The T_m values for anti-HER2 variants as Fab fragments were estimated by differential scanning calorimetry at pH 7.4 (Fig. S6). The K_D values for the anti-HER2 variants as IgG₁ were estimated by surface plasmon resonance at pH 7.4.

Anti-HER2 variant				Tm	HER2
VH	CH1	VL	CL	(˚C)	KD (nM)
Parent	Parent	Parent	Parent	81.9	0.63
Q39E	S183K	Q38K	V133E	77.9	0.75
Q39K	S183E	Q38E	V133K	78.2	0.46
Q39E	yt65	Q38K	yt65	81.4	0.72