Cystine knot scaffold platform

Abstract

Provided are non-naturally occurring cystine knot peptides (CKPs) that bind to VEGF-A. Additionally, provided are methods of using non-naturally occurring CKPs that bind to VEGF-A, including diagnostic and therapeutic compositions and methods. Non-naturally CKPs that bind low density lipoprotein receptor-related protein 6 (LRP6) are also provided.

1 . A non-naturally occurring cystine knot peptide (CKP) that binds to vascular endothelial growth factor A (VEGF-A), wherein the CKP comprises the cystine scaffold structure:
   Z 1 C 1 L1C 2 L2C 3 L3C 4 L4C 5 L5C 6 Z 2      
       wherein:
 Z 1  and Z 2  are any amino acid or an unnatural amino acid; 
 L1 is Loop 1 and has a structure selected from the group consisting of: X 1 X 2 X 3 X 4 X 5 X 6  (SEQ ID NO: 2), X 1 X 2 X 3 X 4 X 5 X 6 X 7  (SEQ ID NO: 3), X 1 X 2 X 3 X 4 X 5 X 6 X 7 X 8  (SEQ ID NO: 4), X 1 X 2 X 3 X 4 X 5 X 6 X 7 X 8 X 9  (SEQ ID NO: 5), and X 1 X 2 X 3 X 4 X 5 X 6 X 7 X 8 X 9 X 10  (SEQ ID NO: 6), wherein each of X 1 -X 10  is any amino acid or an unnatural amino acid; 
 L2 is Loop 2 and has the structure: X 1 X 2 X 3 X 4 X 5  (SEQ ID NO: 7), wherein each of X 1 -X 5  is any amino acid or an unnatural amino acid; 
 L3 is Loop 3 and has the structure: X 1 X 2 X 3  wherein each of X 1 -X 3  is any amino acid or an unnatural amino acid; 
 L4 is Loop 4 and has the structure: X 1 , wherein X 1  is any amino acid or an unnatural amino acid; 
 L5 is Loop 5 and has the structure: X 1 X 2 X 3 X 4 X 5  (SEQ ID NO: 7), wherein each of X 1 -X 5  is any amino acid or an unnatural amino acid; 
 wherein the unnatural amino acid is selected from the group consisting of L-propargylglycine-PEG 6 -, L-sulfotyrosine, L-norleucine, L-1-naphthylalanine, L-2-naphthylalanine, L-2-chlorotryptophan, L-3-fluorotyrosine, L-4-fluorophenylalanine, gamma-benzyl-L-proline, gamma-(4-fluoro-benzyl)-L-proline, 4-OH-L-proline, 4-fluoro-L-proline, 4-[4-(trifluoromethyl)-benzyl]-L-proline, 3,4-difluoro-L-phenylalanine, 3,4-dichloro-L-phenylalanine, 4-chloro-L-phenylalanine, 3-F,4-Cl-L-phenylalanine, 2-pyridone(NH para)-L-alanine, pyridone(NH meta)-L-alanine, 3-(1-N-methyl indole)-L-alanine, 3-(1-N-ethyl indole)-L-alanine, 3-(1-N-isopropyl indole)-L-alanine, 3-(5-aza-indole)-L-alanine, 4-methyl-L-phenylalanine, 2-naphthyl-L-alanine, L-4,4′-biphenylalanine, 3-(3-quinolinyl)-L-alanine, 3-(2-quinolinyl)-L-alanine, 3-(2-quinoxalinyl)-L-alanine, 4-methyl-2-pyridyl-alanine, 4-ethyl-2-pyridyl-L-alanine, benzothiazole-L-alanine, benzothiophene-L-alanine, 3-isoquinolinyl-L-alanine, t-butyl-L-alanine (also known as L-Nepentyl glycine), 3-cyclobutyl-L-alanine, cyclopentyl-L-alanine, 5,5,5-Trifluoro-L-leucine, t-butyl-L-glycine (also known as L-tert-Leucine), L-cyclopentylglycine, L-cyclobutylglycine, 3,4-hydroxy-L-phenylalanine, 3,4-fluoro-L-phenylalanine, 3-fluoro,4-OH-L-phenylalanine, 2-chloro-L-tyrosine, 2-methyl-L-tyrosine, 2-ethyl-L-tyrosine, 4-(naphthalen-1-ol)-L-alanine, D-serine, L-beta-homoserine, L-beta-alanine, N-alpha-methyl glycine, glycine amide, glycine ester of glycerol, glycine ester of glycol, glycine ester of oxetane-3-yl, and glycine morpholine amide;
 wherein the CKP binds to VEGF-A with an affinity of 500 pM or better. 
 
 
     
     
         2 - 24 . (canceled)