中文摘要：

铁氧还蛋白还原酶（Ferredoxin-NADP＋ reductases，FNR）是一种在生物体的多种代谢中起着重要作用的黄素酶. 为探讨嗜水气单胞菌（Aeromonas hydrophila）XS91-4-1中FNR的功能和结构，通过克隆其FNR基因，构建重组表达载体pET42a-fnr，表达并分离纯化了具有活性的GST-FNR融合蛋白，根据米曼氏动力学测定了纯化蛋白对NADPH及EDTA-Fe3＋的酶活力，采用生物信息学方法对XS91-4-1 FNR蛋白序列进行系统学分析，并初步预测了该蛋白三维结构. 结果表明：重组质粒能够在宿主菌大肠杆菌（Escherichia coli）BL21中获得高效可溶性表达，经镍柱亲和层析法可纯化出电泳均一的目的蛋白，蛋白浓度为67.3 μg/mL；纯化蛋白对NADPH的比活力为1.78 U/mg，对EDTA-Fe3＋的比活力为1.13 U/mg，比活力比粗酶分别提高了约29和22倍；生物信息学分析表明XS91-4-1 FNR分布在Bacterial-class FNR分支上且具有与此类FNR相似的结构特点. 上述结果显示嗜水气单胞菌FNR具有与已报道的FNR相似的基本特性，并推测其可能属于Bacterial-class FNR.

英文摘要：

Ferredoxin-NADP＋ reductases （FNRs） are ubiquitous flavoenzymes that play an important role in many organisms. To investigate the structure and function of Aeromonas hydrophila FNR, FNR gene was cloned from A. hydrophila XS91-4-1. Recombinant plastimid pET42a-fnr was constructed and overexpressed in Escherichia coli BL21. FNR-GST recombinant protein was purified by nickel column affinity chromatography. According to Michaelis-Menten equation and double reciprocal plot, the enzyme activity of recombinant protein was assayed using NADPH and EDTA-Fe3＋ as substrate. Then bioinformatics analysis of FNR was performed and three-dimensional structure of FNR was predicted. The results showed that FNR-GST recombinant protein was highly expressed in E. coli BL21 in a soluble form. Its protein concentration was 67.3 μg/mL. The specific activity for NADPH and EDTA-Fe3＋ was 1.78 U/mg and 1.13 U/mg respectively, 29 and 22-fold higher after purification. Based on its sequence and phylogenetic relationship, the FNR of A. hydrophila XS91-4-1 was closely related to bacterial-class FNR. Our study suggested that the FNR of A. hydrophila belongs to bacterial-class FNR, and is similar to FNRs in many fundamental characteristics.