Table 1.

S-peptide analogues used in this study^†

Name	Sequence	ΔΔASAnp, Å2‡	Percent of helix§
Pep-1F¶	ac-YETAAAK′FERQHMDS-NH2	0	21∥
Helix backbone series
A6G	ac-YETAAGK′FERQHMDS-NH2	−28	4
A6P	ac-YETAAPK′FERQHMDS-NH2	35	3
Q11P	ac-YETAAAK′FERPHMDS-NH2	16	10
Side chain series
F8A	ac-YETAAAK′AERQHMDS-NH2	−166	42
H12A	ac-YETAAAK′FERQAMDS-NH2	−64	34
M13A	ac-YETAAAK′FERQHADS-NH2	−103	25
H12A/M13MS⩵O‡‡	ac-YETAAAK′FERQAMS⩵ODS-NH2

^†K′, 5-carboxyfluoresceinyl ^ɛN lysine. 

^‡The predicted effects of mutations on the change in accessible nonpolar surface area associated with forming RNaseS* from isolated S-peptide analogues and native S-protein (see Materials and Methods). 

^§The fractional helicities for the mutant peptides calculated from the Lifson-Roig model with Pep-1F as a reference (see Materials and Methods), unless noted. 

^¶The suffix “1F,” which indicates the presence of 5-carboxyfluorescein, is dropped from the names of the mutants. 

∥ From ref. 11. 

^‡‡M^S⩵O is methionine sulfoxide.