小柯机器人

科学家解析人TG结构
2020-02-12 14:17

英国MRC分子生物学实验室Jan Lwe和斯洛文尼亚蛋白质化学和生物学综合方法卓越中心Dušan Turk课题组合作解析了人类甲状腺球蛋白(TG)的结构。该研究202025日在线发表于国际学术期刊《自然》。

他们用冷冻电镜确定了全长人TG结构,其分辨率约为3.5Å。他们确定了结构中所有的激素酪氨酸对,并使用定点诱变和体外激素生成测定法(使用在HEK293T细胞中表达的人TG)验证了它们。他们的分析表明,酪氨酸的亲和力、柔韧性和溶剂暴露是激素生成位点的关键特征。他们将TG的反应位点转移到无关的细菌麦芽糖结合蛋白(MBP)中的工程化酪氨酸供体-受体对上,从而产生了与TG相当的激素产生。他们的研究为进一步了解甲状腺激素的产生和调节提供了框架。

据了解,甲状腺球蛋白(TG)是甲状腺激素的蛋白质前体,对脊椎动物的生长、发育和代谢控制至关重要。TG的激素合成是通过碘化和酪氨酸对的偶合在甲状腺中发生的,并被TG蛋白水解酶水解后完成。TG中酪氨酸的接近被认为可以实现偶联反应,但激素生成的酪氨酸还未被鉴定,缺乏TG三维结构阻碍了对机制的理解。

附:英文原文

Title: The structure of human thyroglobulin

Author: Francesca Coscia, Ajda Taler-Veri, Veronica T. Chang, Ludwig Sinn, Francis J. OReilly, Thierry Izor, Miha Renko, Imre Berger, Juri Rappsilber, Duan Turk, Jan Lwe

Issue&Volume: 2020-02-05

Abstract: Thyroglobulin (TG) is the protein precursor of thyroid hormones, which are essential for growth, development and the control of metabolism in vertebrates1,2. Hormone synthesis from TG occurs in the thyroid gland via the iodination and coupling of pairs of tyrosines, and is completed by TG proteolysis3. Tyrosine proximity within TG is thought to enable the coupling reaction but hormonogenic tyrosines have not been clearly identified, and the lack of a three-dimensional structure of TG has prevented mechanistic understanding4. Here we present the structure of full-length human thyroglobulin at a resolution of approximately 3.5 , determined by cryo-electron microscopy. We identified all of the hormonogenic tyrosine pairs in the structure, and verified them using site-directed mutagenesis and in vitro hormone-production assays using human TG expressed in HEK293T cells. Our analysis revealed that the proximity, flexibility and solvent exposure of the tyrosines are the key characteristics of hormonogenic sites. We transferred the reaction sites from TG to an engineered tyrosine donor–acceptor pair in the unrelated bacterial maltose-binding protein (MBP), which yielded hormone production with an efficiency comparable to that of TG. Our study provides a framework to further understand the production and regulation of thyroid hormones.

DOI: 10.1038/s41586-020-1995-4

Source: https://www.nature.com/articles/s41586-020-1995-4

Nature:《自然》,创刊于1869年。隶属于施普林格·自然出版集团,最新IF:43.07
官方网址:http://www.nature.com/
投稿链接:http://www.nature.com/authors/submit_manuscript.html


本期文章:《自然》:Online/在线发表

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