Li Lian-Chao, Bedinger Patricia A, Volk Carol, Jones A Daniel, Cosgrove Daniel J
Department of Biology, 208 Mueller Laboratory, 152 Davey Laboratory, The Pennsylvania State University, University Park, Pennsylvania 16802, USA.
Plant Physiol. 2003 Aug;132(4):2073-85. doi: 10.1104/pp.103.020024.
Four proteins with wall extension activity on grass cell walls were purified from maize (Zea mays) pollen by conventional column chromatography and high-performance liquid chromatography. Each is a basic glycoprotein (isoelectric point = 9.1-9.5) of approximately 28 kD and was identified by immunoblot analysis as an isoform of Zea m 1, the major group 1 allergen of maize pollen and member of the beta-expansin family. Four distinctive cDNAs for Zea m 1 were identified by cDNA library screening and by GenBank analysis. One pair (GenBank accession nos. AY104999 and AY104125) was much closer in sequence to well-characterized allergens such as Lol p 1 and Phl p 1 from ryegrass (Lolium perenne) and Phleum pretense, whereas a second pair was much more divergent. The N-terminal sequence and mass spectrometry fingerprint of the most abundant isoform (Zea m 1d) matched that predicted for AY197353, whereas N-terminal sequences of the other isoforms matched or nearly matched AY104999 and AY104125. Highly purified Zea m 1d induced extension of a variety of grass walls but not dicot walls. Wall extension activity of Zea m 1d was biphasic with respect to protein concentration, had a broad pH optimum between 5 and 6, required more than 50 micro g mL(-1) for high activity, and led to cell wall breakage after only approximately 10% extension. These characteristics differ from those of alpha-expansins. Some of the distinctive properties of Zea m 1 may not be typical of beta-expansins as a class but may relate to the specialized function of this beta-expansin in pollen function.
通过常规柱色谱法和高效液相色谱法，从玉米（Zea mays）花粉中纯化出四种对禾本科细胞壁具有壁扩展活性的蛋白质。每种蛋白质都是一种碱性糖蛋白（等电点 = 9.1 - 9.5），分子量约为28 kD，通过免疫印迹分析被鉴定为Zea m 1的一种同工型，Zea m 1是玉米花粉的主要1类变应原，属于β-扩张蛋白家族成员。通过cDNA文库筛选和GenBank分析，鉴定出了四个不同的Zea m 1 cDNA。其中一对（GenBank登录号：AY104999和AY104125）在序列上与已充分表征的变应原，如来自黑麦草（Lolium perenne）和梯牧草（Phleum pretense）的Lol p 1和Phl p 1更为接近，而另一对则差异更大。最丰富的同工型（Zea m 1d）的N端序列和质谱指纹与AY197353预测的序列匹配，而其他同工型的N端序列与AY104999和AY104125匹配或几乎匹配。高度纯化的Zea m 1d可诱导多种禾本科细胞壁的扩展，但不能诱导双子叶植物细胞壁的扩展。Zea m 1d的壁扩展活性相对于蛋白质浓度呈双相性，在pH 5至6之间有较宽的最佳pH范围，高活性需要超过50 μg mL(-1)的浓度，并且在仅约10%的扩展后就会导致细胞壁破裂。这些特性与α-扩张蛋白不同。Zea m 1的一些独特特性可能并非β-扩张蛋白这一类的典型特性，而是可能与该β-扩张蛋白在花粉功能中的特殊作用有关。
