1BH4

CIRCULIN A FROM CHASSALIA PARVIFLORA, NMR, 12 STRUCTURES

1BH4 の概要

• エントリーDOI: 10.2210/pdb1bh4/pdb
• 関連するBIRD辞書のPRD_ID: PRD_000752
• 分子名称: CIRCULIN A (1 entity in total)
• 機能のキーワード: cyclic peptide, cystine knot, anti-hiv activity
• 由来する生物種: Chassalia parviflora
• タンパク質・核酸の鎖数: 1
• 化学式量合計: 3178.80

構造登録者

Daly, N.L.,Koltay, A.,Craik, D.J. (登録日: 1998-06-12, 公開日: 1999-06-15, 最終更新日: 2024-10-23)

主引用文献

Daly, N.L.,Koltay, A.,Gustafson, K.R.,Boyd, M.R.,Casas-Finet, J.R.,Craik, D.J.
Solution structure by NMR of circulin A: a macrocyclic knotted peptide having anti-HIV activity.
J.Mol.Biol., 285:333-345, 1999

PubMed Abstract: The three-dimensional solution structure of circulin A, a 30 residue polypeptide from the African plant Chassalia parvifolia, has been determined using two-dimensional 1H-NMR spectroscopy. Circulin A was originally identified based upon its inhibition of the cytopathic effects and replication of the human immunodeficiency virus. Structural restraints consisting of 369 interproton distances inferred from nuclear Overhauser effects, and 21 backbone dihedral and nine chi1 angle restraints from spin-spin coupling constants were used as input for simulated annealing calculations and energy minimisation in the program X-PLOR. The final set of 12 structures had mean pairwise rms differences over the whole molecule of 0.91 A for the backbone atom, and 1.68 A for all heavy atoms. For the well-defined region encompassing residues 2-12 and 18-27, the corresponding values were 0.71 and 1.66 A, respectively. Circulin A adopts a compact structure consisting of beta-turns and a distorted segment of triple-stranded beta-sheet. Fluorescence spectroscopy provided additional evidence for a solvent-exposed Trp residue. The molecule is stabilised by three disulfide bonds, two of which form an embedded loop completed by the backbone fragments connecting the cysteine residues. A third disulfide bond threads through the centre of this loop to form a "cystine-knot" motif. This motif is present in a range of other biologically active proteins, including omega-contoxin GVIA and Cucurbita maxima trypsin inhibitor. Circulin A belongs to a novel class of macrocyclic peptides which have been isolated from plants in the Rubiaceae family. The global fold of circulin A is similar to kalata B1, the only member of this class for which a structure has previously been determined.

PubMed: 9878410
DOI: 10.1006/jmbi.1998.2276

実験手法

SOLUTION NMR