Functional and structural features of γ‐zeathionins, a new class of sodium channel blockers

FEBS Letters

Santos Cruz, Jáder¹  de Souza Castro, Mariana²  Kushmerick, Christopher⁴  Beirão, Paulo S.L.¹  Bloch, Carlos³ 

[1] Departamento de Bioquı́mica e Imunologia/ICB, UFMG, Belo Horizonte, MG, Brazil;Departamento de Ciências Fisiológicas/IB, Universidade de Brası́lia, 70910-900 Brası́lia, DF, Brazil;Departamento de Quı́mica/IE, Universidade de Brası́lia, 90910-900 Brası́lia, DF, Brazil;Departamento de Farmacologia/ICB, UFMG, Belo Horizonte, MG, Brazil

关键词: Plant defensin;    γ-Thionin;    Sodium channel;    μ-Conotoxin;    Patch clamp;    GH3 cell line;    γ1-Z and γ2-Z;    γ1- and γ2-zeathionins;    2D NMR;    two-dimensional nuclear magnetic resonance spectroscopy;    RP-HPLC;    reverse-phase high-performance liquid chromatography;    TTX;    tetrodotoxin;    STX;    saxitoxin;   

DOI  :  10.1016/S0014-5793(98)01480-X

学科分类：生物化学/生物物理

来源: John Wiley & Sons Ltd.

【 摘 要 】

γ1- and γ2-zeathionins (γ1-Z and γ2-Z) are members of a family of small and basic peptides involved in plant protection. These plant defensins exhibit remarkable structural similarity to scorpion neurotoxins and insect defensins. In the present report, we used the whole-cell patch clamp technique to investigate the inhibition of the sodium current (I _Na) by γ1-Z and γ2-Z in the GH3 cell line. Both γ1-Z and γ2-Z rapidly and reversibly inhibited I _Na without changing the kinetics or voltage dependence of activation or inactivation. To our knowledge, this is the first example of a plant protein that inhibits the sodium channel. From structural comparisons with the μ-conotoxins, a family of peptides that block the sodium channel, we detected some similar features that could provide the basis of inhibition of sodium channels by γ-zeathionins.

【 授权许可】

Unknown