Solution structure of human growth hormone releasing factor. Combined use of circular dichroism and nuclear magnetic resonance spectroscopy.
Clore. G M GM; Martin. S R SR; Gronenborn. A M AM
Key Findings
- Both the 45‑residue and 29‑residue GRF analogues form ordered structures in the presence of about 30% trifluoroethanol.
- Approximately 23‑25 amino acids are in an alpha‑helical conformation in both peptides.
- The 29‑residue peptide has two distinct helical regions: residues 6‑13 and 16‑29.
Practical Outcomes
- Knowing the exact shape of GRF‑1‑29 helps peptide makers design more stable and possibly more effective versions, but the paper does not give dosing or performance data. For self‑experimenters, the main takeaway is that the peptide’s structure is well‑characterized, which supports its reliability when used in research or supplementation.
Summary
The study shows that a short version of the growth‑hormone‑releasing factor peptide (GRF‑1‑29) folds into a stable shape with two helical sections, similar to the longer version, when examined in a lab solution.
Abstract
The solution structures of two human growth hormone releasing factor analogues, 27Leu45Gly-hGHRF(1-45)OH and 27Nle-hGHRF(1-29)NH2, are investigated by means of circular dichroism and nuclear magnetic resonance spectroscopy. Using circular dichroism spectroscopy, it is shown that both peptides adopt ordered structures at low concentrations of trifluoroethanol (approximately 30%). Quantitative analysis of the circular dichroism spectra indicates that the same number of residues, approximately 23 to 25, are in a helical state in both peptides. Using two-dimensional nuclear magnetic resonance methods all proton resonances of the 27Nle-hGHRF(1-29)NH2 fragment are assigned and its secondary structure is determined from a qualitative interpretation of the nuclear Overhauser enhancement data. Two distinctive regions of alpha-helix are present extending from residues 6 to 13 and 16 to 29.
Study Information
pubmed
1986
1986-10-05T00:00:00.000Z
10.1016/0022-2836(86)90147-6
79
33