紫云英非特异性转脂蛋白AsIB259的体外酶活性及在共生固氮中的功能  

Activity in vitro and function of a non-specific lipid transfer protein AsIB259 from Astragalus sinicus in symbiotic nitrogen fixation

作　　者：李一星[1] 王建云[1] 石晓峰[1] 陈大松[1] 李友国[1] 

机构地区：[1]华中农业大学农业微生物学国家重点实验室,武汉430070

出　　处：《华中农业大学学报》2014年第3期19-25,共7页Journal of Huazhong Agricultural University

基　　金：国家自然科学基金项目(31371549;31071346和31000115)

摘　　要：将紫云英AsIB259基因编码的一个预测的非特异性转脂蛋白AsIB259（nsLTP,non-specific lipid transfer protein）在大肠杆菌表达菌株Rosetta 2（DE3）中进行了诱导表达,体外测定AsIB259蛋白的脂质结合动力学特征,检测它对不同碳链长度脂肪酸及其衍生物的结合能力,进一步考查AsIB259超表达对紫云英毛根结瘤情况的影响。结果表明：AsIB259具有转脂蛋白的典型特征,与16～22碳链长度脂肪酸的结合活性较强,对茉莉酸也表现出一定的结合活性;AsIB259超表达导致根瘤数量增加1.5倍且固氮酶活性降低,说明该基因在根瘤形成和固氮过程中发挥重要作用。AsIB259 encodes a putative non-specific lipid transfer protein in Astragalus sinicus. AsIB259 protein was overexpressed in Escherichia coli Rosetta 2（DE3）and the kinetics of the recombinant protein binding to P-96 fluorescence probe was examined.Simultaneously,its capacity of binding to different fatty acids and fatty acid derivatives was measured as well.Furthermore,the symbiotic phenotype associated with AsIB259 overexpression was investigated.The results showed that AsIB259 displayed high binding activity toward fatty acids with 16-22 carbon chain length;and its overexpression in hairy roots led to an increase of 1.5-fold nodule number,but to a decrease of nitrogenase activity.The results indicated that AsIB259 may play an important role in nodulation and nitrogen fixation.

关 键 词：非特异性转脂蛋白 AsIB259 体外表达 脂质结合活性 共生固氮 

分 类 号：S154.381[农业科学—土壤学]