A compound represented by Formula A-1: T-L -X 5 -X 6 -X 7 -X 8 -X 9 -X 10 -X 11 -X 12 -X 13 -X 14 -X 15 -X 16 -X 17 -X 18 -X 19 -X 20 -X 21 -R 1; or a pharmaceutically acceptable salt thereof, wherein: L is a linking selected from: C, C, S 2, N(R 3)S*, N(R 3)S* 2, N(R 3)C*, N(R 3)C*, OC*, OC*, SC*, SC*, C(=NH), and N(R 3)C*(=NH); wherein L is bonded to the N terminal nitrogen of X 5 at the atom marked with an asterisk (*) and R 3 is selected from: H, D, (C 1 -C 6)alkyl, (C 2 -C 6)alkenyl, (C 2 -C 6)alkynyl, (C 1 -C 6)alkoxy, (C 3 -C 9)cycloalkyl, 5-10 membered heterocycloalkyl, aryl, aryloxy, heteroaryloxy, aralkyl, heteroaryl, and heteroaralkyl; wherein said alkyl, alkenyl, alkynyl, alkoxy, cycloalkyl, heterocycloalkyl, aryl, aryloxy, heteroaryloxy, aralkyl, heteroaryl, and heteroaralkyl are optionally and independently substituted; T is a lipophilic tether moiety that promotes penetration of the compound into the cell membrane and tethers the compound to the cell membrane and is bonded to L; and R 1 is OR 2 or N(R 2) 2, each R 2 is independently H or alkyl, and wherein: X 5 is a glycine residue, a methyl serine residue, a homoserine residue, a propargyl glycine residue or a cysteine residue, X 6 is a glycine residue, X 7 is a tyrosine residue, X 8 is a glutamine residue, X 9 is a lysine residue, X 10 is a lysine residue, X 11 is a leucine residue, a proline residue, a photoleucine, a histidine, or a d-leucine, X 12 is an arginine residue, X 13 is a serine residue, a d-proline residue, a proline residue, or a hydroxyproline residue, X 14 is an alanine residue, a homoserine residue, a histidine residue, a methyl serine residue, a proline residue, a Dpr residue, a methionine residue, a tryptophan residue, a hydroxyproline residue, or a d-proline residue, X 15 is a threonine residue or a histidine residue, X 16 is aspartic acid residue, or a threonine residue X 17 is a lysine residue, or an aspartic acid residue, X 18 is a tyrosine residue, a lysine residue or a phenylalanine residue, X 19 is an arginine residue or a tryptophan residue, X 20 is a leucine residue or an arginine residue, X 21 is a histidine residue or a leucine residue or absent. L is a linking selected from: C, C, S 2, N(R 3)S*, N(R 3)S* 2, N(R 3)C*, N(R 3)C*, OC*, OC*, SC*, SC*, C(=NH), and N(R 3)C*(=NH); wherein L is bonded to the N terminal nitrogen of X 5 at the atom marked with an asterisk (*) and R 3 is selected from: H, D, (C 1 -C 6)alkyl, (C 2 -C 6)alkenyl, (C 2 -C 6)alkynyl, (C 1 -C 6)alkoxy, (C 3 -C 9)cycloalkyl, 5-10 membered heterocycloalkyl, aryl, aryloxy, heteroaryloxy, aralkyl, heteroaryl, and heteroaralkyl; wherein said alkyl, alkenyl, alkynyl, alkoxy, cycloalkyl, heterocycloalkyl, aryl, aryloxy, heteroaryloxy, aralkyl, heteroaryl, and heteroaralkyl are optionally and independently substituted; T is a lipophilic tether moiety that promotes penetration of the compound into the cell membrane and tethers the compound to the cell membrane and is bonded to L; and R 1 is OR 2 or N(R 2) 2, each R 2 is independently H or alkyl, and wherein: X 5 is a glycine residue, a methyl serine residue, a homoserine residue, a propargyl glycine residue or a cysteine residue, X 6 is a glycine residue, X 7 is a tyrosine residue, X 8 is a glutamine residue, X 9 is a lysine residue, X 10 is a lysine residue, X 11 is a leucine residue, a proline residue, a photoleucine, a histidine, or a d-leucine, X 12 is an arginine residue, X 13 is a serine residue, a d-proline residue, a proline residue, or a hydroxyproline residue, X 14 is an alanine residue, a homoserine residue, a histidine residue, a methyl serine residue, a proline residue, a Dpr residue, a methionine residue, a tryptophan residue, a hydroxyproline residue, or a d-proline residue, X 15 is a threonine residue or a histidine residue, X 16 is aspartic acid residue, or a threonine residue X 17 is a lysine residue, or an aspartic acid residue, X 18 is a tyrosine residue, a lysine residue or a phenylalanine residue, X 19 is an arginine residue or a tryptophan residue, X 20 is a leucine residue or an arginine residue, X 21 is a histidine residue or a leucine residue or absent. X 5 is a glycine residue, a methyl serine residue, a homoserine residue, a propargyl glycine residue or a cysteine residue, X 6 is a glycine residue, X 7 is a tyrosine residue, X 8 is a glutamine residue, X 9 is a lysine residue, X 10 is a lysine residue, X 11 is a leucine residue, a proline residue, a photoleucine, a histidine, or a d-leucine, X 12 is an arginine residue, X 13 is a serine residue, a d-proline residue, a proline residue, or a hydroxyproline residue, X 14 is an alanine residue, a homoserine residue, a histidine residue, a methyl serine residue, a proline residue, a Dpr residue, a methionine residue, a tryptophan residue, a hydroxyproline residue, or a d-proline residue, X 15 is a threonine residue or a histidine residue, X 16 is aspartic acid residue, or a threonine residue X 17 is a lysine residue, or an aspartic acid residue, X 18 is a tyrosine residue, a lysine residue or a phenylalanine residue, X 19 is an arginine residue or a tryptophan residue, X 20 is a leucine residue or an arginine residue, X 21 is a histidine residue or a leucine residue or absent.