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Solution conformation on bovine growth hormone releasing factor by 1 H NMR and molecular modeling
Author(s) -
Kweon Jeehye,
Lee Ho-Jin,
Kim Young-Man,
Choi Young-Sang,
Lee Kang-Bong
Publication year - 1999
Publication title -
febs letters
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.593
H-Index - 257
eISSN - 1873-3468
pISSN - 0014-5793
DOI - 10.1016/s0014-5793(99)00976-x
Subject(s) - chemistry , nuclear overhauser effect , two dimensional nuclear magnetic resonance spectroscopy , crystallography , nuclear magnetic resonance spectroscopy , circular dichroism , spectroscopy , protein secondary structure , stereochemistry , protein structure , physics , biochemistry , quantum mechanics
The structure of bovine growth hormone releasing factor (bGHRF) consisting of 44 amino acids has been studied in CD and 1 H nuclear magnetic resonance (NMR) spectroscopy in conjunction with molecular modeling. Since bGHRF does not have an ordered structure in water alone, a 30% 2,2,2‐trifluoroethanol (TFE) aqueous solvent was used to induce considerable α‐helical structures, which corresponds to a helical content of ∼62% as determined by circular dichroism (CD). The secondary structure was obtained from nuclear Overhauser enhancement and 3 J HNα coupling constant in 30% TFE solution. Three‐dimensional structures consistent with NMR data were generated by using distance geometry calculation. A set of 267 interproton distances derived from nuclear Overhauser effect correlation spectroscopy (NOESY) experiments and coupling constants were used. From the initial random conformations, 50 distance geometry structures with minimal violations were selected for further refinement. The 14 best structures were obtained after simulated annealing calculation with energy minimization. The structure of bGHRF in 30% TFE solution was characterized by one α‐helix (residues 8–19), two poorly constrained helices (residues 23–27 and residues 31–34) and a β I(III)‐turn fragment (residues 20–23; φ i+1 =−53.1°, Ψ i+1 =−19.6°, φ i+2 =−59.9°, Ψ i+2 =−20.6°) connected by the segments of less defined structures in N‐terminal and Ω‐shaped flexible C‐terminal determined from NOESY cross peaks between helical segment (residues 14–18) and tail fragment (residues 42–44). The obtained structure will play an important role toward the understanding of the structural and functional role of the GHRF.