Radauer Christian, Breiteneder Heimo
Department of Pathophysiology, Center of Physiology and Pathophysiology, Medical University of Vienna, Vienna, Austria.
J Allergy Clin Immunol. 2006 Jan;117(1):141-7. doi: 10.1016/j.jaci.2005.09.010. Epub 2005 Nov 28.
Inhalative allergies are elicited predominantly by pollen of various plant species. However, a classification of the large number of identified pollen allergens is still missing.
To analyze pollen allergen sequences with respect to protein family membership, taxonomic distribution of protein families, and interspecies variability.
Protein family memberships of all plant allergen sequences from the Allergome database were determined by using the Protein Families Database of Alignments and Hidden Markov Models. The taxonomic distribution of pollen allergens was established from the Integrated Taxonomic Information System. Members of abundant pollen allergen families were compared with allergenic and nonallergenic homologues by database similarity searches and multiple sequence alignments.
Pollen allergens were classified into 29 of 7868 protein families. Expansins, profilins, and calcium-binding proteins constitute the major pollen allergen families, whereas most plant food allergens belong to the prolamin, cupin, or profilin families. Pollen allergens were revealed to be ubiquitous (eg, profilins), present in certain plant families (eg, pectate lyases), or limited to a single taxon (eg, thaumatin-like proteins). Allergenic plant profilins constitute a highly conserved family with sequence identities of 70% to 85% among each other but low identities of 30% to 40% with nonallergenic profilins from other eukaryotes, including human beings. Similarly, allergenic polcalcins possess sequence identities of 64% to 92% but show low identities of 39% to 42% to related nonallergenic calmodulins and calmodulin-like proteins from vegetative plant tissues and man.
This classification of pollen allergens into protein families will aid in predicting cross-reactivity, designing comprehensive diagnostic devices, and assessing the allergenic potential of novel proteins.
吸入性过敏主要由各种植物物种的花粉引发。然而，大量已鉴定的花粉过敏原仍缺乏分类。
分析花粉过敏原序列的蛋白质家族成员、蛋白质家族的分类分布以及种间变异性。
使用比对和隐马尔可夫模型的蛋白质家族数据库确定来自Allergome数据库的所有植物过敏原序列的蛋白质家族成员。从综合分类信息系统确定花粉过敏原的分类分布。通过数据库相似性搜索和多序列比对，将丰富的花粉过敏原家族成员与致敏和非致敏同源物进行比较。
花粉过敏原被归类到7868个蛋白质家族中的29个。伸展蛋白、肌动蛋白结合蛋白和钙结合蛋白构成主要的花粉过敏原家族，而大多数植物性食物过敏原属于醇溶蛋白、豆球蛋白或肌动蛋白结合蛋白家族。花粉过敏原被发现无处不在（如肌动蛋白结合蛋白）、存在于某些植物家族中（如果胶酸裂解酶）或局限于单个分类单元（如类甜蛋白）。致敏植物肌动蛋白结合蛋白构成一个高度保守的家族，彼此之间的序列同一性为70%至85%，但与包括人类在内的其他真核生物的非致敏肌动蛋白结合蛋白的同一性较低，为30%至40%。同样，致敏钙结合蛋白具有64%至92%的序列同一性，但与来自植物营养组织和人类的相关非致敏钙调蛋白和类钙调蛋白的同一性较低，为39%至42%。
这种将花粉过敏原分类为蛋白质家族的方法将有助于预测交叉反应性、设计综合诊断设备以及评估新型蛋白质的致敏潜力。
