Pectin degrading glycoside hydrolases of family 28: sequence-structural features, specificities and evolution
Pectin degrading glycoside hydrolases of family 28: sequence-structural features, specificities and evolution
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DOI：
10.1093/protein/14.9.615
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发表时间：
2001-09-01
期刊：
影响因子：
--
通讯作者：
Janecek, S
中科院分区：
文献类型：
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作者：
Markovic, O;Janecek, S
家族28属于糖苷水解酶的最大家族。它涵盖了细菌、真菌、植物和昆虫来源的几种酶的特异性。本研究涉及家族28成员的所有可用氨基酸序列。首先，它侧重于115个序列的多聚半乳糖醛酸酶产生其进化树的详细分析。大的数据集允许修改现有的家族28序列特征中的一些，并绘制细菌和真菌外切多聚半乳糖醛酸酶特异性的序列特征，将它们与内切多聚半乳糖醛酸酶区分开。进化树反映了分类学和特异性，因此细菌，真菌和植物酶形成了自己的集群，也尊重了内和外作用模式。唯一的昆虫（动物）代表是最相关的真菌内切多聚半乳糖醛酸酶。本研究进一步带来：（i）可用的鼠李糖半乳糖醛酸酶序列的分析;（ii）最近添加的成员，内切木半乳糖醛酸水解酶和家庭的其余部分之间的相关性的阐明;和（iii）揭示的序列特征的个别酶的特异性和整个家庭内的进化关系28。还提出了个别酶组共有的二硫化物。关于多聚半乳糖醛酸酶的功能上重要的残基，木半乳糖醛酸聚糖水解酶具有所有这些残基，而已知缺乏组氨酸残基（His 223;尼日尔多聚半乳糖醛酸酶II编号）的鼠李糖半乳糖醛酸酶具有被保守色氨酸取代的另外的酪氨酸（Tyr 291）。在进化上，木半乳糖醛酸聚糖水解酶与真菌外切多聚半乳糖醛酸酶最相关，而鼠李糖半乳糖醛酸酶在相邻的分支上形成它们自己的簇。
Family 28 belongs to the largest families of glycoside hydrolases. It covers several enzyme specificities of bacterial, fungal, plant and insect origins. This study deals with all available amino acid sequences of family 28 members. First, it focuses on the detailed analysis of 115 sequences of polygalacturonases yielding their evolutionary tree. The large data set allowed modification of some of the existing family 28 sequence characteristics and to draw the sequence features specific for bacterial and fungal exopolygalacturonases discriminating them from the endopolygalacturonases. The evolutionary tree reflects both the taxonomy and specificity so that bacterial, fungal and plant enzymes form their own clusters, the endo- and exo-mode of action being respected, too. The only insect (animal) representative is most related to fungal endopolygalacturonases. The present study brings further: (i) the analysis of available rhamnogalacturonase sequences; (ii) the elucidation of relatedness between the recently added member, the endo-xylogalacturonan hydrolase and the rest of the family; and (iii) revealing the sequence features characteristic of the individual enzyme specificities and the evolutionary relationships within the entire family 28. The disulfides common for the individual enzyme groups were also proposed. With regard to functionally important residues of polygalacturonases, xylogalacturonan hydrolase possesses all of them, while the rhamnogalacturonases, known to lack the histidine residue (His223; Aspergillus niger polygalacturonase II numbering), have a further tyrosine (Tyr291) replaced by a conserved tryptophan. Evolutionarily, the xylogalacturonan hydrolase is most related to fungal exopolygalacturonases and the rhamnogalacturonases form their own cluster on the adjacent branch.