透明颤菌血红蛋白基因的研究与应用

总结了近 15年来透明颤菌血红蛋白的研究结果 ,包括它的分布、结构、功能、合成等分子生物学以及在基因工程中的应用。透明颤菌的血红蛋白是 2 0世纪 70年代被发现的 ,由于它具有结合氧的特性 ,可使透明颤菌这一专性好氧的革兰氏阴性菌在贫氧环境中生长。透明颤菌血红蛋白是同型二聚体形式的可溶性血红蛋白分子 ,每分子透明颤菌血红蛋白由两个分子量为 15 775的亚基和两个b型血红素组成。透明颤菌血红蛋白的功能是为透明颤菌强大的呼吸膜增加氧的流量。完整的有功能的血红蛋白由血红蛋白亚基和血红素组成 ,血红蛋白亚基由基因vgb编码 ,血红素由生化代谢合成。透明颤菌血红蛋白基因在野生透明颤菌中是以单拷贝的方式随染色体一起复制表达的。透明颤菌血红蛋白基因已经被克隆和测序。同时也讨论了将透明颤菌血红蛋白基因整合到异源宿主菌中增加重组蛋白产量和发酵产量方面的研究。最后 ,概述了当透明颤菌血红蛋白在植物中表达时 ,转基因植物表现出生长增加以及代谢物产量发生变化的情况。

The Studies and Applications of Vitreoscilla Hemoglobin (vgb)

In this review we summary main studying results of Vitreoscilla Hb ( VHb ) for last fifteen years, including its distribution, structure, function, genetics and molecular biology, and usefulness as a genetic engineering tool. Vitreoscilla Hb was found in 1970's. The VHb is thought to aid Vitreoscilla's obligately aerobic host's survival in the microaerobic environments. Vitreoscilla Hb is a homodimeric molecule, consisting of two identical subunits of 15.7kDa along with two protohemes IX per molecule. It may function to enable the organism to survive in oxygen-limited environments by acting as an oxygen storage-trap or to facilitate oxygen diffusion. The whole and functioning VHb is consists of hemoglobin subunits and hemes. The gene vgb encodes the hemoglobin subunit. The heme is synthesized from biochemical process. A single copy of the vgb gene on the Vitreoscilla genome was identified after Southern blot analysis. The gene encoding VHb,vgb, has been isolated, sequenced and characterized. It is also discussed to integrate heterologous bacterial hosts with vgb for purpose of enhancing production of recombinant protein and fermentation products. Finally, we illustrate the studying advance on VHb transgenic plants enhanced growth and altered metabolite production when VHb is expressed in plants.