1RYV

Three dimensional solution structure of the K27A MUTANT of sodium channels inhibitor HAINANTOXIN-IV BY 2D 1H-NMR

1RYV の概要

• エントリーDOI: 10.2210/pdb1ryv/pdb
• 関連するPDBエントリー: 1NIY 1RYG
• NMR情報: BMRB: 6066
• 分子名称: Hainantoxin-IV (1 entity in total)
• 機能のキーワード: neurotoxin, inhibitor cystine knot motif, toxin
• タンパク質・核酸の鎖数: 1
• 化学式量合計: 3941.53

構造登録者

Li, D.,Lu, S.,Gu, X.,Liang, S. (登録日: 2003-12-22, 公開日: 2004-01-13, 最終更新日: 2024-10-30)

主引用文献

Li, D.,Xiao, Y.,Xu, X.,Xiong, X.,Lu, S.,Liu, Z.,Zhu, Q.,Wang, M.,Gu, X.,Liang, S.
Structure--activity relationships of hainantoxin-IV and structure determination of active and inactive sodium channel blockers
J.Biol.Chem., 279:37734-37740, 2004

PubMed Abstract: Hainantoxin-IV (HNTX-IV) can specifically inhibit the neuronal tetrodotoxin-sensitive sodium channels and defines a new class of depressant spider toxin. The sequence of native HNTX-IV is ECLGFGKGCNPSNDQCCKSSNLVCSRKHRWCKYEI-NH(2). In the present study, to obtain further insight into the primary and tertiary structural requirements of neuronal sodium channel blockers, we determined the solution structure of HNTX-IV as a typical inhibitor cystine knot motif and synthesized four mutants designed based on the predicted sites followed by structural elucidation of two inactive mutants. Pharmacological studies indicated that the S12A and R26A mutants had activities near that of native HNTX-IV, while K27A and R29A demonstrated activities reduced by 2 orders of magnitude. (1)H MR analysis showed the similar molecular conformations for native HNTX-IV and four synthetic mutants. Furthermore, in the determined structures of K27A and R29A, the side chains of residues 27 and 29 were located in the identical spatial position to those of native HNTX-IV. These results suggested that residues Ser(12), Arg(26), Lys(27), and Arg(29) were not responsible for stabilizing the distinct conformation of HNTX-IV, but Lys(27) and Arg(29) were critical for the bioactivities. The potency reductions produced by Ala substitutions were primarily due to the direct interaction of the essential residues Lys(27) and Arg(29) with sodium channels rather than to a conformational change. After comparison of these structures and activities with correlated toxins, we hypothesized that residues Lys(27), Arg(29), His(28), Lys(32), Phe(5), and Trp(30) clustered on one face of HNTX-IV were responsible for ligand binding.

PubMed: 15201273
DOI: 10.1074/jbc.M405765200

実験手法

SOLUTION NMR