TABLE 1.

Experimental restraints used to guide docking of PP with hY₄R

hY4R residue	PP residue	Low resolution restraint	High resolution restraint	Proposed interaction	Steps imposed	Experimental evidence
Tyr2.64	Tyr27	C-β atoms within 8 Å	None	Unknown	hPP helix placement	Table 2 (Tyr2.64 and Tyr27 single mutants)
Asp6.59	Arg35	C-β atoms within 8 Å	Asp6.59 O-δ and Arg35 NH within 4 Å	Salt bridge	hPP C-terminal folding (low resolution), hY4R loop building (low resolution), final relaxation (high resolution)	Ref. 20 (Asp6.59 and Arg35 single mutants)
Asn7.32	Arg33	C-β atoms within 8 Å	Asn7.32 O-δ and Arg33 NH within 4 Å	Hydrogen bond	hPP C-terminal folding (low resolution), hY4R loop building (low resolution), final relaxation (high resolution)	Table 5, Fig. 5B (Asp7.32 and Arg33 single mutants)
Phe7.35	Arg33	C-β atoms within 8 Å	None	π-cation stacking	hPP C-terminal folding (low resolution), hY4R loop building (low resolution), final relaxation (high resolution)	Ref. 50, Table 4 (Phe7.35 and Arg33 single mutants)
Phe7.35	Tyr36	None	Phe7.35 CZ and Tyr36 CZ within 4 Å	Unknown	Final relaxation (high resolution)	Table 6, Fig. 6 (Phe7.35 and Tyr36 single mutants)