Reactive peptide labeling
Provided herein are sulfo n-hydroxysuccimidyl ester (sulfo-SE) linked peptides, methods of synthesis thereof, and methods of using such peptides for labeling of biomolecules. In particular, peptides comprising non-alkyl group such as serine, threonine, cysteine, tyrosine, glutamic acid, and aspartic acid are stably modified (e.g., without autoreactivity) with a sulfo-SE group and used to label or otherwise modify biomolecules.
1. A composition comprising a peptide linked to a sulfo n-hydroxysuccimidyl ester (sulfo-SE) group, wherein the peptide does not comprise a cysteine or lysine residue.
2. The composition of claim 1 , wherein the sulfo-SE group is linked to the N-terminus, C-terminus, or an amino acid sidechain of the peptide.
3. The composition of claim 1 , wherein the peptide comprises at least one non-alkyl amino acid selected from serine, threonine, tyrosine, glutamic acid, arginine, histidine, tryptophan and aspartic acid.
4. The composition of claim 3 , wherein the at least one reactive non-alkyl amino acid is an arginine or tyrosine.
5. The composition of claim 1 , wherein the sulfo-SE group is linked to the peptide by a non-peptide linker group.
6. The composition of claim 1 , wherein the peptide is 4-50 amino acids in length.
7. The composition of claim 1 , wherein the peptides comprise a fluorophore or chromophore conjugate.
8. The composition of claim 1 , wherein the peptide is a component of a biomolecular complex.
9. The composition of claim 1 , wherein the peptide comprises an amino acid sequence having 5 or fewer amino acid substitutions relative to SmBiT (SEQ ID NO: 10) SEQ ID NO: 10 (SmBiT).
10. The composition of claim 1 , wherein the peptide comprises Pep691 (SEQ ID NO: 23) or SmBiT (SEQ ID NO: 10).
11. A method of labeling a biomolecule with a peptide comprising contacting the biomolecule with a composition of claim 1 , under conditions such that the sulfo-SE group reacts with an amine on the biomolecule.
12. The method of claim 11 , wherein the amine is a primary amine.
13. The method of claim 11 , wherein the biomolecule is selected from the group consisting of an antigen, an antibody, an antibody fragment, a nanobody, a darpin, a non-antibody protein, a receptor, a ligand, a toxin, a cytokine, a nucleic acid, a nucleoprotein complex, a peptide, an amino acid, a sugar, a drug, and streptavidin.
14. A composition comprising a biomolecule labeled with a peptide of claim 1 .
15. A method comprising:
(a) contacting the composition of claim 14 with an analyte, wherein the analyte is linked to a complementary polypeptide capable of forming a bioluminescent complex with the peptide on the biomolecule;
(b) contacting the bioluminescent complex with a substrate for the bioluminescent complex; and
(c) detecting luminescence.
16. The method of claim 15 , wherein the analyte is selected from the group consisting of an antigen, an antibody, an antibody fragment, a nanobody, a darpin, a non-antibody protein, a receptor, a ligand, a toxin, a cytokine, a nucleic acid, a nucleoprotein complex, a peptide, an amino acid, a sugar, a drug, and streptavidin.
17. A composition comprising an analyte labeled with a peptide of claim 1 .
18. A method comprising:
(a) contacting the composition of claim 17 with a biomolecule, wherein the biomolecule is linked to a complementary polypeptide capable of forming a bioluminescent complex with the peptide on the analyte;
(b) contacting the bioluminescent complex with a substrate for the bioluminescent complex; and
(c) detecting luminescence, fluorescence, and/or bioluminescence resonance energy transfer (BRET).
19. A composition comprising an analyte labeled with a first peptide linked to a first sulfo n-hydroxysuccimidyl ester (sulfo-SE) group, wherein the first peptide does not comprise a cysteine or lysine residue and a biomolecule labelled with a second peptide linked to a second sulfo n-hydroxysuccimidyl ester (sulfo-SE) group, wherein the second peptide does not comprise a cysteine or lysine residue, wherein the first and second peptides are capable of forming a bioluminescent complex in the presence of a complementary polypeptide.
20. A method comprising:
(a) contacting the analyte and biomolecule of claim 19 with the complementary polypeptide and forming the bioluminescent complex;
(b) contacting the bioluminescent complex with a substrate for the bioluminescent complex; and
(c) detecting luminescence.
21. The method of claim 20 , wherein the first peptide or the second peptide is a fluorophore or chromophore-conjugated peptide and further comprising detecting fluorescence/light and/or BRET from the bioluminescent complex to the fluorophore or chromophore.