Ahlgren J A, Ordal G W
Biochem J. 1983 Sep 1;213(3):759-63. doi: 10.1042/bj2130759.
The amino acid residue modified in the reversible methylation of Bacillus subtilis methyl-accepting chemotaxis proteins was identified as glutamic acid; methylation results in the formation of glutamate 5-methyl ester. Identification was made by comparing the behaviour of a 3H-labelled compound isolated from proteolytically hydrolysed methyl-accepting chemotaxis proteins labelled in vivo with that of authentic methylated amino acids by chromatographic and electrophoretic techniques. Also, the isolated compound on mild alkaline hydrolysis shows behaviour identical with that of authentic glutamate 5-methyl ester. [3H]Methanol released by mild alkaline hydrolysis was made to react with 3,5-dinitrobenzyl chloride to form [3H]methyl 3,5-dinitrobenzoate, which was identified by reverse-phase high-pressure liquid chromatography.
在枯草芽孢杆菌甲基受体趋化蛋白可逆甲基化过程中被修饰的氨基酸残基被鉴定为谷氨酸;甲基化导致形成谷氨酸5 - 甲酯。通过用色谱和电泳技术比较从体内标记的经蛋白水解的甲基受体趋化蛋白中分离出的3H标记化合物与真实甲基化氨基酸的行为来进行鉴定。此外,分离出的化合物在温和碱性水解时表现出与真实谷氨酸5 - 甲酯相同的行为。温和碱性水解释放出的[3H]甲醇与3,5 - 二硝基苄基氯反应形成[3H] - 3,5 - 二硝基苯甲酸甲酯,通过反相高压液相色谱对其进行鉴定。