Evolution of the membrane-bound fatty acid desaturases
Evolution of the membrane-bound fatty acid desaturases
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DOI：
10.1016/s0305-1978(03)00041-3
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发表时间：
2003-10-01
影响因子：
1.6
通讯作者：
Vilches, MA
中科院分区：
文献类型：
--
作者：
Alonso, DL;García-Maroto, F;Vilches, MA
推导的膜结合去饱和酶基因的氨基酸序列进行了比较，以推断它们的系统发育关系。所有推导的蛋白质共享三个高度保守的富含组氨酸的基序，表明一个共同的起源。系统发育分析显示，三个不同的集群内的膜去饱和酶。一个簇由Δ 9去饱和酶序列组成，第二组包括Δ 12/ω 3去饱和酶，第三簇包括所谓的“前端”去饱和酶，即Δ 5、Δ 6和Δ 8去饱和酶。基于功能数据，Delta 9去饱和酶基因被认为是其余膜去饱和酶基因的祖先。第二簇的排列表明ω 3去饱和酶起源于来自Delta 12去饱和酶基因的原核谱系。前两个集群基本上与传统的物种树一致，因为不同的去饱和酶类内的排列反映了有关生物的进化关系。相反，在“前端”去饱和酶集群，系统发育和功能数据表明，Delta 5去饱和酶基因起源独立于不同的进化谱系从祖先Delta 6去饱和酶。此外，Delta 8去饱和酶似乎在植物中从Delta 6去饱和酶基因进化了一次。来自高等植物的前端去饱和酶基因的可用基因组序列是无内含子的，而来自低等植物和动物的那些是分裂的。这些研究结果的进化意义进行了讨论。(C)2003爱思唯尔科技有限公司版权所有。
The deduced amino acid sequences of the membrane-bound desaturase genes have been compared in order to infer their phylogenetic relationships. All the deduced proteins share three highly conserved histidine rich motifs suggesting a common origin. The phylogenetic analysis revealed three distinct clusters within the membrane desaturases. One cluster consisted of Delta9 desaturase sequences, the second group included the Delta12/omega3 desaturases, and the third cluster comprised the so called 'front-end' desaturases, namely Delta5, Delta6 and Delta8 desaturases. Based on functional data the Delta9 desaturase gene is assumed to be the ancestor of the remaining membrane desaturase genes. The arrangement of the second cluster suggest that omega3 desaturases originated in a prokaryotic lineage from a Delta12 desaturase gene. The first two clusters were essentially consistent with conventional species trees, as the arrangement within the different desaturase classes reflected the evolutionary relationships of the organisms concerned. Conversely, within the 'front-end' desaturase cluster, phylogenetic and functional data indicate that Delta5 desaturase genes originated independently in different evolutionary lineages from an ancestral Delta6 desaturase. In addition, Delta8 desaturases seem to have evolved once in plants from a Delta6 desaturase gene. Available genomic sequences of front-end desaturase genes from higher plants are intronless, while those from lower plants and animals are split. Evolutionary implications of these findings are discussed. (C) 2003 Elsevier Science Ltd. All rights reserved.