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Structure-Function Studies of Analogues of Parathyroid Hormone (PTH)-1-34 Containing beta-Amino Acid Residues in Positions 11-13
- Source :
- Biochemistry (Easton) 41 (2002): 8162–8175., info:cnr-pdr/source/autori:Peggion E., Mammi S., Schievano E., Silvestri L., Scheibler L., Bisello A., Rosenblatt M., Chorev M./titolo:Structure-Function Studies of Analogues of Parathyroid Hormone (PTH)-1-34 Containing beta-Amino Acid Residues in Positions 11-13/doi:/rivista:Biochemistry (Easton)/anno:2002/pagina_da:8162/pagina_a:8175/intervallo_pagine:8162–8175/volume:41
- Publication Year :
- 2002
- Publisher :
- American Chemical Society., [Easton, Pa.], Stati Uniti d'America, 2002.
-
Abstract
- The 1-34 N-terminal fragments of human parathyroid hormone (PTH) and PTH-related protein (PTHrP) elicit the full spectrum of bone-relevant activities characteristic of the intact hormones. The structural elements believed to be required for receptor binding and biological activity are two helical segments, one N-terminal and one C-terminal, connected by hinges or flexible points located around positions 12 and 19. To test this hypothesis, we synthesized and characterized the following analogues of PTH-(1-34), each containing single or double substitutions with beta-amino acid residues around the putative hinge located at position 12: I. [Nle(8,18),beta-Ala(11,12),Nal(23),Tyr(34)]bPTH-(1-34)NH(2); II. [Nle(8,18),beta-Ala(12,13),Nal(23),Tyr(34)]bPTH-(1-34)NH(2); III. [Nle(8,18),beta-Ala(11),Nal(23),Tyr(34)]bPTH-(1-34)NH(2); IV. [Nle(8,18),beta-hLeu(11),Nal(23),Tyr(34)]bPTH-(1-34)NH(2); V. [Nle(8,18),beta-Ala(12), Nal(23),Tyr(34)]bPTH-(1-34)NH(2); VI. [Nle(8,18),beta-Ala(13), Nal(23),Tyr(34)]bPTH-(1-34)NH(2) (beta-hLeu = beta-homo-leucine; beta-Ala = beta-alanine; Nal = L-2-naphthyl-alanine; Nle = norleucine). Analogues I and III exhibit very low binding affinity and are devoid of adenylyl cyclase activity. Analogue II, despite its very low binding capacity is an agonist. Biological activity and binding capacity are partially restored in analogue IV, and completely restored in analogues V and VI. The conformational properties of the analogues were investigated in aqueous solution containing dodecylphosphocholine (DPC) micelles as a membrane-mimetic environment using CD, 2D-NMR, and molecular dynamics calculations. All peptides fold partially into the alpha-helical conformation in the presence of DPC micelles, with a maximum helix content in the range of 30-35%. NMR analysis reveals the presence of two helical segments, one N-terminal and one C-terminal, as a common structural motif in all analogues. Incorporation of beta-Ala dyads at positions 11,12 and 12,13 in analogues I and II, respectively, enhances the conformational disorder in this portion of the sequence but also destabilizes the N-terminal helix. This could be one of the possible reasons for the lack of biological activity in these analogues. The partial recovery of binding affinity and biological activity in analogue IV, compared to the structurally similar analogue III, is clearly the consequence of the reintroduction of Leu side-chain of the native sequence. In the fully active analogues V and VI, the helix stability at the N-terminus is further increased. Taken together, these results stress the functional importance of the conformational stability of the helical activation domain in PTH-(1-34). Contrary to expectation, insertion of a single beta-amino acid residue in positions 11, 12, or 13 in analogues III-VI does not favor a disordered structure in this portion of the sequence.
- Subjects :
- Circular dichroism
Protein Conformation
Stereochemistry
Molecular Sequence Data
Norleucine
Ligands
Biochemistry
Protein Structure, Secondary
Cell Line
Structure-Activity Relationship
chemistry.chemical_compound
Protein structure
Leucine
Cyclic AMP
Humans
Structure–activity relationship
Amino Acid Sequence
Structural motif
Nuclear Magnetic Resonance, Biomolecular
Peptide sequence
Circular Dichroism
Parathyroid Hormone-Related Protein
Proteins
Biological activity
Peptide Fragments
Amino Acid Substitution
chemistry
Parathyroid Hormone
Helix
beta-Alanine
Receptors, Parathyroid Hormone
Thermodynamics
Protons
Subjects
Details
- Database :
- OpenAIRE
- Journal :
- Biochemistry (Easton) 41 (2002): 8162–8175., info:cnr-pdr/source/autori:Peggion E., Mammi S., Schievano E., Silvestri L., Scheibler L., Bisello A., Rosenblatt M., Chorev M./titolo:Structure-Function Studies of Analogues of Parathyroid Hormone (PTH)-1-34 Containing beta-Amino Acid Residues in Positions 11-13/doi:/rivista:Biochemistry (Easton)/anno:2002/pagina_da:8162/pagina_a:8175/intervallo_pagine:8162–8175/volume:41
- Accession number :
- edsair.doi.dedup.....faf0f9d419eb7943b38c03cbbbabdbbd