硫酸化酪氨酸探針之設計

Abstract

蛋白酪氨酸硫酸化是一種轉譯後修飾，此修飾在生理上有重要的功能。但是被發現硫酸化的蛋白量很少。目前磷酸化的酪氨酸已經有商品化的探針可以辨識被，但硫酸化的酪氨酸沒有。因此我們參考可辨識被磷酸化酪氨酸的探針，利用它結合磷酸的策略設計硫酸化酪氨酸的探針，以研究硫酸化蛋白質體。本實驗使用磷酸探針，一個磷酸探針類似物，次氮基三乙酸以及3-（（2-氨基苯基）氨基甲醯基）苯甲酸與錳，鈷，鎳，銅，鋅，鈣，鍶及鋇的二價離子形成錯合物，然後測試這些錯合物與苯基磷酸或4-硝基苯基硫酸的結合力。實驗結果顯示，次氮基三乙酸/鍶或鋇可以與4-硝基苯基硫酸有結合能力，且次氮基三乙酸/鋇有較好的選擇性。根據這些結果可知鋇離子具有成為磷酸探針中心離子的潛力。因此，未來將專注在次氮基三乙酸的修飾以增加硫酸化酪氨酸探針的效能。

Protein tyrosine O-sulfation is a post-translational modification (PTM) which was first observed in 1954. Tyrosine-sulfated proteins play the important roles in many biological processes. However, few sulfated proteins have been found by proteomics. Nowadays, protein tyrosine phosphorylation can be recognized by a commercial probe called Phos-tag but no sulf-tag was discovered and applied to sulfoproteomics. Therefore, the specific aim of this study is to design a series of sulf-tags similar to Phos-tag for the enrichment of sulfotyrosine peptides for sulfoproteomics study. We used Phos-tag, a Phos-tag analog, nitrilotriacetic acid and 3-((2-Aminophenyl)carbamoyl)benzoic acid to form complexes with Mn2+, Co2+, Ni2+, Cu2+, Zn2+ ,Ca2+, Sr2+, Ba2+, and then measured the binding ability between complexes and phenyl phosphate and 4-nitrophenyl sulfate respectively. The results showed that nitrilotriacetic acid/Sr2+ and Ba2+ could bind to 4-nitrophenyl sulfate, and nitrilotriacetic acid/Ba2+ had higher selectivity than nitrilotriacetic acid/Sr2+. On the basis of these results, Ba2+ might be the best potential metal ion to build the ideal model for pho-stag. In the future, we will focus on the modification of nitrilotriacetic acid to improve the sulf-tag.