Joshi C P, Chiang V L
Plant Biotechnology Research Center, Institute of Wood Research, School of Forestry and Wood Products, Michigan Technological University, Houghton 49931, USA.
Plant Mol Biol. 1998 Jul;37(4):663-74. doi: 10.1023/a:1006035210889.
Plant S-adenosyl-L-methionine-dependent methyltransferases (SAM-Mtases) are the key enzymes in phenylpropanoid, flavonoid and many other metabolic pathways of biotechnological importance. Here we compiled the amino acid sequences of 56 SAM-Mtases from different plants and performed a computer analysis for the conserved sequence motifs that could possibly act as SAM-binding domains. To date, genes or cDNAs encoding at least ten distinct groups of SAM-Mtases that utilize SAM and a variety of substrates have been reported from higher plants. Three amino acid sequence motifs are conserved in most of these SAM-Mtases. In addition, many conserved domains have been discovered in each group of O-methyltransferases (OMTs) that methylate specific substrates and may act as sites for substrate specificity in each enzyme. Finally, a diagrammatic representation of the relationship between different OMTs is presented. These SAM-Mtase sequence signatures will be useful in the identification of SAM-Mtase motifs in the hitherto unidentified proteins as well as for designing primers in the isolation of new SAM-Mtases from plants.
植物S-腺苷-L-甲硫氨酸依赖性甲基转移酶（SAM-甲基转移酶）是苯丙烷类、类黄酮及许多其他具有生物技术重要性的代谢途径中的关键酶。在此，我们汇集了来自不同植物的56种SAM-甲基转移酶的氨基酸序列，并对可能作为SAM结合结构域的保守序列基序进行了计算机分析。迄今为止，已从高等植物中报道了编码至少十组利用SAM和多种底物的不同SAM-甲基转移酶的基因或cDNA。在大多数这些SAM-甲基转移酶中，有三个氨基酸序列基序是保守的。此外，在每组对特定底物进行甲基化的O-甲基转移酶（OMT）中发现了许多保守结构域，这些结构域可能作为每种酶中底物特异性的位点。最后，给出了不同OMT之间关系的示意图。这些SAM-甲基转移酶序列特征将有助于鉴定迄今未鉴定蛋白质中的SAM-甲基转移酶基序，以及在从植物中分离新的SAM-甲基转移酶时设计引物。
