1SRB

CONFORMATIONAL STUDIES ON SRTB, A NON-SELECTIVE ENDOTHELIN RECEPTOR AGONIST, AND ON IRL 1620, AN ETB RECEPTOR SPECIFIC AGONIST

1SRB の概要

• エントリーDOI: 10.2210/pdb1srb/pdb
• 分子名称: Sarafotoxins precursor (1 entity in total)
• 機能のキーワード: toxin
• 由来する生物種: Atractaspis microlepidota andersoni
• 細胞内の位置: Secreted: P13208
• タンパク質・核酸の鎖数: 1
• 化学式量合計: 2570.98

構造登録者

Smith, R.,Atkins, A.R. (登録日: 1994-09-06, 公開日: 1994-11-01, 最終更新日: 2024-10-23)

主引用文献

Atkins, A.R.,Martin, R.C.,Smith, R.
1H NMR studies of sarafotoxin SRTb, a nonselective endothelin receptor agonist, and IRL 1620, an ETB receptor-specific agonist.
Biochemistry, 34:2026-2033, 1995

PubMed Abstract: 1H NMR studies on the nonselective endothelin receptor agonist sarafotoxin SRTb have identified a helix between residues Asp 8 and His 16, and a beta-turn involving residues Cys 3 to Met 6; however, the biologically important C-terminal five residues were found to be conformationally variable. The average RMSD, measured for the final 43 refined structures to the average structure over residues 1-16, was 0.78 +/- 0.18 A for the backbone atoms and 1.39 +/- 0.22 A for all atoms. The torsion angles Cys 3 psi/Lys 4 theta, Thr 7 psi/Asp 8 theta and Gln 17 theta were identified as sites of conformational variability. Differences were found between the structures in the bicyclic loop region for SRTb and those published for ET1, another nonselective receptor agonist, which may explain the observed differences in potency of these peptides. The conformation of an ETB receptor-specific agonist, IRL 1620, which lacks the N-terminal seven residues and the two intrachain disulfides, was found by NMR and circular dichroism spectroscopy to be predominantly random coil, despite the fact that its affinity for the ETB receptor almost equals that of ET1. However, close analysis of the NMR results indicated the presence of turn-like structures, or a nascent helix, in the part of the sequence corresponding to the helical region in the parent peptides. These results suggest that the helical conformation may be required for ligand binding to the ETB receptor as well as to the ETA receptor.

PubMed: 7849060
DOI: 10.1021/bi00006a024

実験手法

SOLUTION NMR