Koeduka Takao, Nakabo Ako, Takata Ami, Ikeda Ryo, Suzuki Hideyuki, Kitajima Sakihito, Ozaki Shin-Ichi
Graduate School of Sciences and Technology for Innovation, Yamaguchi University, Yamaguchi 753-8515, Japan.
Department of Research and Development, Kazusa DNA Research Institute, Chiba 292-0818, Japan.
Plant Biotechnol (Tokyo). 2024 Mar 25;41(1):65-70. doi: 10.5511/plantbiotechnology.23.1224a.
SABATH proteins methylate the carboxyl groups or nitrogen atoms of small plant molecules and play important roles in many developmental processes and plant defense responses. Previous studies have shown that indole-3-acetic acid (IAA) carboxyl methyltransferase (IAMT), a member of the SABATH methyltransferase family, converts IAA into its methyl ester (Me-IAA). We used RNA-seq analysis to identify a putative gene, , in the ancient angiosperm . Functional characterization of the recombinant IaIAMT protein expressed in showed the highest level of activity with IAA, whereas indole-3-propionic acid and indole-3-butyric acid were not used as substrates. The apparent value of IaIAMT using IAA as a substrate was determined to be 122 µM. Phylogenetic analysis and structural modeling of IaIAMT suggested that IaIAMT evolved independently from IAMTs isolated from other plant species, whereas strict substrate specificity toward IAA was conserved in species, as observed in other plants.
SABATH蛋白使植物小分子的羧基或氮原子甲基化，在许多发育过程和植物防御反应中发挥重要作用。先前的研究表明，吲哚-3-乙酸（IAA）羧基甲基转移酶（IAMT）是SABATH甲基转移酶家族的成员，可将IAA转化为其甲酯（Me-IAA）。我们使用RNA测序分析在古老被子植物中鉴定出一个假定基因。在中表达的重组IaIAMT蛋白的功能表征显示，其对IAA的活性水平最高，而吲哚-3-丙酸和吲哚-3-丁酸未用作底物。以IAA为底物时，IaIAMT的表观值被确定为122µM。IaIAMT的系统发育分析和结构建模表明，IaIAMT是从其他植物物种分离出的IAMT独立进化而来的，而在物种中观察到，与其他植物一样，对IAA具有严格的底物特异性。
