Laboratory of Biochemistry and Glycobiology, Department of Molecular Biotechnology, Ghent University, Coupure Links 653, 9000 Ghent, Belgium.
BMC Plant Biol. 2009 Nov 23;9:136. doi: 10.1186/1471-2229-9-136.
Cloning of the Euonymus lectin led to the discovery of a novel domain that also occurs in some stress-induced plant proteins. The distribution and the diversity of proteins with an Euonymus lectin (EUL) domain were investigated using detailed analysis of sequences in publicly accessible genome and transcriptome databases.
Comprehensive in silico analyses indicate that the recently identified Euonymus europaeus lectin domain represents a conserved structural unit of a novel family of putative carbohydrate-binding proteins, which will further be referred to as the Euonymus lectin (EUL) family. The EUL domain is widespread among plants. Analysis of retrieved sequences revealed that some sequences consist of a single EUL domain linked to an unrelated N-terminal domain whereas others comprise two in tandem arrayed EUL domains. A new classification system for these lectins is proposed based on the overall domain architecture. Evolutionary relationships among the sequences with EUL domains are discussed.
The identification of the EUL family provides the first evidence for the occurrence in terrestrial plants of a highly conserved plant specific domain. The widespread distribution of the EUL domain strikingly contrasts the more limited or even narrow distribution of most other lectin domains found in plants. The apparent omnipresence of the EUL domain is indicative for a universal role of this lectin domain in plants. Although there is unambiguous evidence that several EUL domains possess carbohydrate-binding activity further research is required to corroborate the carbohydrate-binding properties of different members of the EUL family.
Euonymus lectin 的克隆导致发现了一个新的结构域，该结构域也存在于一些应激诱导的植物蛋白中。使用公共基因组和转录组数据库中序列的详细分析，研究了具有 Euonymus lectin（EUL）结构域的蛋白质的分布和多样性。
综合的计算机分析表明，最近鉴定的 Euonymus europaeus lectin 结构域代表了一种新型假定糖结合蛋白家族的保守结构单元，我们将其进一步称为 Euonymus lectin（EUL）家族。EUL 结构域在植物中广泛存在。对检索到的序列进行分析表明，一些序列由单个 EUL 结构域与不相关的 N 端结构域相连，而另一些序列则由两个串联排列的 EUL 结构域组成。基于整体结构域架构，提出了一种针对这些凝集素的新分类系统。讨论了具有 EUL 结构域的序列之间的进化关系。
EUL 家族的鉴定首次提供了在陆地植物中存在高度保守的植物特异性结构域的证据。EUL 结构域的广泛分布与植物中发现的大多数其他凝集素结构域的更有限或甚至狭窄分布形成鲜明对比。EUL 结构域的明显普遍存在表明该凝集素结构域在植物中具有普遍作用。虽然有明确的证据表明，几个 EUL 结构域具有碳水化合物结合活性，但需要进一步研究来证实 EUL 家族不同成员的碳水化合物结合特性。
