Table 2.

Examples of application of mutagenesis in design of peptide binders.

Starting point	Target	Results
The structure of the APY hairpin bound to the receptor	EphA4 receptor	Kd as low as 30 nM [47]
C-terminal binding domain of the peptide	C5a Receptor	Series of agonists with a range of ki values as low as 1 μM [48]
Structure of CDK2-cyclin	Cyclin	IC50 values as low as 2.1 $\pm$ 0.4 μM [39]
Helix segment from HIV-1 gp41 structure	gp41	Ki values < 0.2 nM after mutating to new a/B AA [49]
pDI inhibitor discovered through phage display [50], binding motif from p53	MDM2/MDMX	KD of 0.91 nM for MDM2 and 2.31 nM for MDMX after mutagenesis including ncAAs and crosslinking [51], $4\pm 8$ nM and $50\pm 16$ nM against MDM2 and MDMX after adding a res that binds in a newly identified pocket [46]
Helical motif of SARS-COV2 bound to Human ACE-2	ACE-2	Showed better computational energies for designed binder [44]
Short helical segment from TRF1TRFH-Fbx4G structure	ubiquitin E3 ligase SCFFbx4	kD as low as 23.3 ± 12.8 μM and IC50 of 31.3 μM after mutagenesis [52]