An internally cross-linked polypeptide comprising the amino acid sequence A 0 B 0 C 0 D 0 E 0 F 0 G 0 A 1 B 1 C 1 D 1 E 1 F 1 G 1 A 2 B 2 (SEQ ID NO:1) wherein: A 0 is F or a conservative amino acid substitution; B 0 is F or a conservative amino acid substitution; C 0 is G or a conservative amino acid substitution; D 0 is I or a conservative amino acid substitution; E 0 is Y or a conservative amino acid substitution; F 0 is L or a conservative amino acid substitution; G 0 is T or a conservative amino acid substitution; A 1 is N or a conservative amino acid substitution; B 1 is I or a conservative amino acid substitution; C 1 is L, or a conservative amino acid substitution; D 1 is K, or a conservative amino acid substitution; E 1 is T or a conservative amino acid substitution; F 1 is E or a conservative amino acid substitution; G 1 is E, or a conservative amino acid substitution; or C 1 is K or K substituted with guanine nucleoside or guanine nucleoside analog and D 1 is R; or G 1 is K or K substituted with guanine nucleoside or guanine nucleoside analog and D 1 is R; A 2 is G or a conservative amino acid substitution; B 2 is N or a conservative amino acid substitution; wherein the side chains of two amino acids separated by two, three, or six amino acids are replaced by an internal hydrocarbon staple; the side chains of three amino acids are replaced by internal hydrocarbon staples and/or an internal hydrocarbon stitch; the side chains of four amino acids are replaced by internal hydrocarbon staples, internal hydrocarbon stiches, or a combination of internal hydrocarbon staples and stiches; or the side chains of at least four amino acids are replaced by internal hydrocarbon staples, internal hydrocarbon stiches, or a combination of internal hydrocarbon staples and stiches, the cross-linked polypeptide binds KRAS; and the conservative amino acid substitution is the replacement of an amino acid with another amino acid residue having a similar side chain, wherein K, R and H have a similar side chain; D and E have a similar side chain; G, N, Q, S, T, Y, C have a similar side chain; A, V, L, I, P, F, M, W have a similar side chain; T, V and I have a similar side chain; and Y, F, W and H have a similar side chain. A 0 is F or a conservative amino acid substitution; B 0 is F or a conservative amino acid substitution; C 0 is G or a conservative amino acid substitution; D 0 is I or a conservative amino acid substitution; E 0 is Y or a conservative amino acid substitution; F 0 is L or a conservative amino acid substitution; G 0 is T or a conservative amino acid substitution; A 1 is N or a conservative amino acid substitution; B 1 is I or a conservative amino acid substitution; C 1 is L, or a conservative amino acid substitution; D 1 is K, or a conservative amino acid substitution; E 1 is T or a conservative amino acid substitution; F 1 is E or a conservative amino acid substitution; G 1 is E, or a conservative amino acid substitution; or C 1 is K or K substituted with guanine nucleoside or guanine nucleoside analog and D 1 is R; or G 1 is K or K substituted with guanine nucleoside or guanine nucleoside analog and D 1 is R; A 2 is G or a conservative amino acid substitution; B 2 is N or a conservative amino acid substitution; wherein the side chains of two amino acids separated by two, three, or six amino acids are replaced by an internal hydrocarbon staple; the side chains of three amino acids are replaced by internal hydrocarbon staples and/or an internal hydrocarbon stitch; the side chains of four amino acids are replaced by internal hydrocarbon staples, internal hydrocarbon stiches, or a combination of internal hydrocarbon staples and stiches; or the side chains of at least four amino acids are replaced by internal hydrocarbon staples, internal hydrocarbon stiches, or a combination of internal hydrocarbon staples and stiches, the cross-linked polypeptide binds KRAS; and the conservative amino acid substitution is the replacement of an amino acid with another amino acid residue having a similar side chain, wherein K, R and H have a similar side chain; D and E have a similar side chain; G, N, Q, S, T, Y, C have a similar side chain; A, V, L, I, P, F, M, W have a similar side chain; T, V and I have a similar side chain; and Y, F, W and H have a similar side chain.