Radiation Damage and Racemic Protein Crystallography Reveal the Unique Structure of the GASA/Snakin Protein Superfamily.
Radiation Damage and Racemic Protein Crystallography Reveal the Unique Structure of the GASA/Snakin Protein Superfamily.
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DOI：
10.1002/anie.201602719
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发表时间：
2016-07
影响因子：
--
通讯作者：
Ho-Lun Yeung;C. Squire;Y. Yosaatmadja;S. Panjikar;G. López;A. Molina;E. Baker;P. Harris;M. Brim
中科院分区：
文献类型：
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作者：
Ho-Lun Yeung;C. Squire;Y. Yosaatmadja;S. Panjikar;G. López;A. Molina;E. Baker;P. Harris;M. Brim
Gasa/Snakin超家族蛋白在植物蛋白质组中很常见，具有多种功能，包括激素串扰、发育和防御。Snakin-1是这个家族的63个残基之一，是一种来自土豆的抗菌蛋白，以前曾以完全活性的形式通过化学合成过。本文报道了由外消旋蛋白质结晶和辐射损伤诱导定相(RIP)相结合确定的Snakin-1的1.5？结构。以化学合成的d-和L-蛋白为原料，制备了蛇毒蛋白-1外消旋晶体和含有非天然4-碘苯丙氨酸残基的准外消旋晶体。准外消旋晶体中C-I键的断裂有利于RIP结构的确定。晶体结构显示了一个独特的具有六个二硫键交联键的蛋白质折叠，呈现出一个独特的静电表面，可能会将蛋白质靶向微生物细胞表面。
Proteins from the GASA/snakin superfamily are common in plant proteomes and have diverse functions, including hormonal crosstalk, development, and defense. One 63-residue member of this family, snakin-1, an antimicrobial protein from potatoes, has previously been chemically synthesized in a fully active form. Herein the 1.5 Å structure of snakin-1, determined by a novel combination of racemic protein crystallization and radiation-damage-induced phasing (RIP), is reported. Racemic crystals of snakin-1 and quasi-racemic crystals incorporating an unnatural 4-iodophenylalanine residue were prepared from chemically synthesized d- and l-proteins. Breakage of the C-I bonds in the quasi-racemic crystals facilitated structure determination by RIP. The crystal structure reveals a unique protein fold with six disulfide crosslinks, presenting a distinct electrostatic surface that may target the protein to microbial cell surfaces.