Functional investigation of two 1-aminocyclopropane-1-carboxylate (ACC) synthase-like genes in the moss Physcomitrella patens
Functional investigation of two 1-aminocyclopropane-1-carboxylate (ACC) synthase-like genes in the moss Physcomitrella patens
复制标题
苔藓小立碗藓中两个 1-氨基环丙烷-1-羧酸 (ACC) 合酶样基因的功能研究
DOI：
10.1007/s00299-015-1923-5
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发表时间：
2016-04-01
影响因子：
6.2
通讯作者：
Wang, Ning Ning
中科院分区：
文献类型：
--
作者：
Sun, Lifang;Dong, Hui;Wang, Ning Ning
关键信息小立碗藓中的两个ACC裂解酶样蛋白PpACL 1没有ACS活性，PpACL 1是一个L-胱氨酸/L-半胱氨酸C-S裂解酶。然而，ACS同源物在P. patens中的功能尚未研究。在本研究中，我们从P. patens基因组中克隆了两个推定的ACS基因，即PpACS-Like 1和PpACS-Like 2，并研究其编码的蛋白质是否具有体外和体内ACS活性。使用纯化的PpACL 1和PpACL 2的体外生化测定表明，这两种蛋白质都没有ACS活性。随后，我们产生了表达35 S：PpACL 1和35 S：PpACL 2的转基因拟南芥系，并发现过表达这些蛋白质中的任一种的转基因黄化幼苗缺乏组成型三重响应表型，并且不释放过量水平的乙烯，这表明PpACS-Like蛋白质都不具有体内ACS活性。此外，我们发现PpACL 1作为C-S裂解酶，使用L-胱氨酸和L-半胱氨酸作为底物，而不是作为氨基转移酶。总之，这些结果表明，PpACL 1和PpACL 2不是真正的ACS基因，因为那些在高等植物中发现的。
Key messageTwo ACC synthase-like (ACL) proteins in the mossPhyscomitrella patenshave no ACS activity, and PpACL1 functions as anl-cystine/l-cysteine C-S lyase.AbstractThe ethylene biosynthetic pathway has been well characterized in higher plants, and homologs of a key enzyme in this pathway, ACS, have been reported in several algae and mosses, including Physcomitrella patens. However, the function of the ACS homologs in P. patens has not been investigated. In this research, we cloned two putative ACS genes from the P. patens genome, namely PpACS-Like 1 and 2, and investigated whether their encoded proteins had in vitro and in vivo ACS activity. In vitro biochemical assays using purified PpACL1 and PpACL2 showed that neither protein had ACS activity. Subsequently, we generated transgenic Arabidopsis lines expressing 35S:PpACL1 and 35S:PpACL2, and found that the transgenic etiolated seedlings that overexpressed either of these proteins lacked the constitutive triple response phenotype and did not emit excess levels of ethylene, indicating that neither of the PpACS-Like proteins had in vivo ACS activity. Furthermore, we found that PpACL1 functions as a C-S lyase that uses l-cystine and l-cysteine as substrates, rather than as an aminotransferase. Together, these results indicated that PpACL1 and PpACL2 are not true ACS genes as those found in higher plants.