[巴西固氮螺菌Yu62中nifA基因的克隆测序、表达模式及功能分析]

[Cloning sequencing and expression pattern, functional analysis of nifA gene in Azospirillum brasilense Yu62].

作者信息

Wang J, Chen S, Ma L, Li J

机构信息

College of Biology Science, China Agricultural University, Beijing 100094, China.

出版信息

Wei Sheng Wu Xue Bao. 2001 Dec;41(6):655-61.

PMID:12552819

Abstract

The nifA gene of Azospirillum brasilense Yu62 was cloned and sequenced. The expression of nifA gene was investigated in wild type strain Azospirillum brasilense Yu62. The results show that expression of nifA gene is not repressed by ammounium and oxygen completely. But the expression of Yu62 nifA gene is different from that of strain Sp7 nifA gene. Expression of Yu62 nifA seems more sensitive to oxygen than that of Sp7 nifA which shows the highest expression in condition of aerobic, while the Yu62 nifA gene shows the highest expression in the condition of microaerobic. The regulation of NifA protein activity by ammonia and oxygen was investigated. Results showed that the NifA protein is repressed by ammonia, 1 mmol/L NH4Cl can inhibit activity of NifA protein completely. Oxygen concentration affects activity of NifA protein. NifA protein is highly active in 0.4%-0.5% O2.

摘要

克隆并测序了巴西固氮螺菌Yu62的nifA基因。对野生型菌株巴西固氮螺菌Yu62中nifA基因的表达进行了研究。结果表明，nifA基因的表达并未完全受到铵和氧的抑制。但是Yu62 nifA基因的表达与菌株Sp7 nifA基因的表达不同。Yu62 nifA的表达似乎比Sp7 nifA对氧更敏感，Sp7 nifA在有氧条件下表达最高，而Yu62 nifA基因在微氧条件下表达最高。研究了氨和氧对NifA蛋白活性的调控。结果表明，NifA蛋白受到氨的抑制，1 mmol/L NH4Cl可完全抑制NifA蛋白的活性。氧浓度影响NifA蛋白的活性。NifA蛋白在0.4%-0.5% O2中具有高活性。