Hamberger Björn, Hahlbrock Klaus
Max Planck Institute for Plant Breeding Research, Carl-von-Linné-Weg 10, 50829 Cologne, Germany.
Proc Natl Acad Sci U S A. 2004 Feb 17;101(7):2209-14. doi: 10.1073/pnas.0307307101. Epub 2004 Feb 9.
4-Coumarate:CoA ligase (4CL; EC 6.2.1.12) has a pivotal role in the biosynthesis of plant secondary compounds at the divergence point from general phenylpropanoid metabolism to several major branch pathways. In Arabidopsis thaliana, we have identified a previously undetected, fourth and final member of the At4CL gene family. The encoded enzyme, At4CL4, exhibits the rare property of efficiently activating sinapate, besides the usual 4CL substrates (4-coumarate, caffeate, and ferulate), indicating a distinct metabolic function. Phylogenetic analysis suggests an early evolutionary and functional divergence of three of the four gene family members, At4CL2-4, whereas At4CL1 appears to have originated much later by duplication of its structurally and functionally closest relative, At4CL2. Various characteristics shared by all known plant 4CL genes, as well as by the encoded proteins, define and delimit the At4CL gene family and distinguish it from the closely related family of "At4CL-like" genes.
4-香豆酸：辅酶A连接酶（4CL；EC 6.2.1.12）在植物次生化合物生物合成中起着关键作用，处于从一般苯丙烷代谢到几个主要分支途径的分歧点。在拟南芥中，我们鉴定出了拟南芥4CL（At4CL）基因家族中一个先前未被发现的、也是最后一个成员。编码的酶At4CL4除了能有效激活常见的4CL底物（4-香豆酸、咖啡酸和阿魏酸）外，还具有有效激活芥子酸的罕见特性，这表明它具有独特的代谢功能。系统发育分析表明，四个基因家族成员中的三个，即At4CL2 - 4，在进化和功能上出现了早期分歧，而At4CL1似乎是通过其结构和功能最接近的亲属At4CL2的复制在更晚的时候起源的。所有已知植物4CL基因以及编码蛋白共有的各种特征，定义并界定了At4CL基因家族，并将其与密切相关的“At4CL样”基因家族区分开来。
