A lectin protein（SFL） with molecular weight about 32 kD which markedly agglutinated rabbit and human red blood cells was purified from the roots of Sophora flavescens Ait. This protein, and apparently inhibited the growth of Fusarium vasinfectum Atk., Gibberella saubinetii (Mont.) Sacc., and Piricularia oryzae Cav. A set of degenerate PCR primer was synthesized according to the N-terminal sequence of the purified protein. The full-length cDNA coding the lectin was cloned by RT-PCR and 5′-RACE and sequenced (GenBank AF285121). The deduced amino acid sequence indicates that a preprotein with 284 amino acid residues is firstly translated and then processed to a mature protein with 254 amino acids. A N-Glycosylation site is the Asn 182 residue.
苦参凝集素蛋白基因的分离克隆
马志刚1 鄢波1 黄兴奇1 王铃仙1 曾仲奎2
（1. 云南省农业科学院生物技术研究所，昆明650223；2. 四川大学生物系，成都610064）
摘要：自苦参(Sophora flavescens Ait.)块根中分离得到一种32 kD的凝集素蛋白(SFL),其对兔血及人的4种血型都具有很强的凝集活性,对棉花枯萎病菌(Fusarium vasinfectum Atk.)、小麦赤霉病菌(Gibberella saubinetii (Mont.) Sacc.)和水稻稻瘟病菌(Piricularia oryzae Cav.)的生长有明显抑制作用.依此凝集素蛋白N端部分氨基酸序列合成引物,通过5′、3′_RACE技术,从苦参块根总RNA中克隆到了编码这一凝集素蛋白的全长cDNA序列(已注册GenBank, AF285121).根据全长cDNA序列推导这一cDNA序列编码一个284个氨基酸的前体蛋白,而分离得到的凝集素蛋白为一个254个氨基酸残基的成熟蛋白,在其第182位点含一个N糖基化位点N-L-S.
关键词： 苦参；凝集素；抑菌活性；基因克隆
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