Pectin methylesterases: sequence-structural features and phylogenetic relationships
Pectin methylesterases: sequence-structural features and phylogenetic relationships
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DOI：
10.1016/j.carres.2004.06.023
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发表时间：
2004-09-13
影响因子：
3.1
通讯作者：
Janecek, S
中科院分区：
文献类型：
--
作者：
Markovic, O;Janecek, S
果胶甲酯酶（PMEs）是由细菌、真菌和高等植物产生的酶。它们属于碳水化合物酯酶家族CE-8。本研究对该家族127个氨基酸序列进行了比较分析，其中包括5个特征序列片段：44_GxYxE、113_QAVAL、135_QDTL、157_DFIFG、223_LGRPW（胡萝卜编号）。鉴定出6个保守残基（Gly 44、Gly 154、Asp 157、Gly 161、Arg 225和Trp 227）和6个保守残基（Ile 39、Ser 86、Ser 137、Ile 152、Ile 159和Leu 223）。创建了一组70个具有代表性的PME。将序列进行比对，并计算基于比对的进化树。该树反映了分类：真菌和细菌的PME形成了自己的集群，植物酶被分为八个独立的分支。来自河岸葡萄属的植物PME与真菌属于同一分支。三个植物分支（植物1，2和3）是相对同质的，反映了高度的相互序列同一性。分支植物4含有来自花部分（主要来自花粉）的PME，并且是异质的，像分支植物1a和2a，其还表现出中间特征。分支植物X1和X2位于树中接近微生物分支，代表非典型植物PME。考虑到剩余的植物PME，制备了扩展的植物比对和树（具有大多数拟南芥和水稻酶）。一个排他的拟南芥比对和树表明存在一个新的植物分支X3。在大多数植物酶的前原区中，在PME的N-末端之前发现了一个较长的含有碱性二肽的保守片段R（K）/R（K）。这在进化枝植物XI和大多数进化枝植物X2中未观察到。本研究进一步描述了前体序列和成熟酶中潜在的糖基化位点以及重要的氨基酸残基，如谷氨酸、半胱氨酸、组氨酸和其他芳香族残基（Tyr、Phe和Trp），并讨论了它们在PME活性中的可能功能。(C)2004 Elsevier Ltd.保留所有权利。
Pectin methylesterases (PMEs) are enzymes produced by bacteria, fungi and higher plants. They belong to the carbohydrate esterase family CE-8. This study deals with comparison of 127 amino acid sequences of this family containing the five characteristic sequence segments: 44_GxYxE, 113_QAVAL, 135_QDTL, 157_DFIFG, 223_LGRPW (Daucus carota numbering). Six strictly conserved residues (Gly44, Gly154, Asp157, Gly161, Arg225 and Trp227) and six conservative ones (Ile39, Ser86, Ser137, Ile152, Ile159 and Leu223) were identified. A set of 70 representative PMEs was created. The sequences were aligned and the evolutionary tree based on the alignment was calculated. The tree reflected the taxonomy: the fungal and bacterial PMEs formed their own clusters and the plant enzymes were grouped into eight separate clades. The plant PME from Vitis riparia was placed in a common clade with fungi. Three plant clades (Plant 1, 2 and 3) were relatively homogenous reflecting high degree of mutual sequence identity. The clade Plant 4 contained PMEs from flower parts (mostly form pollen) and was heterogenous, like the clades Plant 1a and 2a, which moreover exhibit an intermediate character. The clades Plant X1 and X2 were situated in the tree close to microbial clades and represented atypical plant PMEs. Taking into account the remaining plant PMEs, an expanded plant alignment and tree (with most Arabidopsis thaliana and Oryza sativa enzymes), were prepared. An exclusive Arabidopsis alignment and tree indicated the existence of a new plant clade X3. In the pre pro region of most plant enzymes a longer conserved segment containing basic dipeptide, R(K)/R(K), that precedes the N-terminal end of PME was revealed. This was not observed in the clade Plant XI and majority of the clade Plant X2. This study brings further the description of occurrence of potential glycosylation sites in pre pro sequences and in mature enzymes as well as important amino acid residues, such as aspartates, cysteines, histidines and other aromatic residues (Tyr, Phe and Trp), with discussion of their possible function in the activity of PMEs. (C) 2004 Elsevier Ltd. All rights reserved.