NUCLEOTIDE-SEQUENCES AND MUTATIONAL ANALYSIS OF THE STRUCTURAL GENES FOR NITROGENASE-2 OF AZOTOBACTER-VINELANDII
NUCLEOTIDE-SEQUENCES AND MUTATIONAL ANALYSIS OF THE STRUCTURAL GENES FOR NITROGENASE-2 OF AZOTOBACTER-VINELANDII
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DOI：
10.1128/jb.172.6.3400-3408.1990
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发表时间：
1990-06-01
影响因子：
3.2
通讯作者：
BISHOP, PE
中科院分区：
文献类型：
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作者：
JOERGER, RD;LOVELESS, TM;BISHOP, PE
测定了棕色固氮菌固氮酶2(V-固氮酶)结构基因的基因组序列(6,559个碱基对)。该区域存在的开放阅读框被组织成两个转录单位。一个含有vnfH(编码二氮原酶还原酶2)和一个铁氧还蛋白样的开放阅读框架(Fd)。第二个包括vnfD(编码α。二氮原酶2的亚基)、vnfG(编码类似于β的产物。来自嗜铬假单胞菌的二固氮酶2的亚基)和vnfK(编码β。二氮原酶2亚基)。VnfH和vnfD的5‘-侧翼区含有类似于NTRA依赖启动子的序列。这种基因安排允许vnfH-fd和vnfDKG的独立表达。携带vnfH插入片段的突变菌株(CA80和CA11.80)仍然能够合成α。和测试版。脱氮酶2的亚基在无氮、缺钼、含V的培养基中生长。一株在vnfDGK区域携带缺失加插入突变的菌株(RP1.11)产生二氮原酶还原酶2。
The nucleotide sequence (6,559 base pairs) of the genomic region containing the structural genes for nitrogenase 2 (V nitrogenase) from Azotobacter vinelandii was determined. The open reading frames present in this region are organized into two transcriptional units. One contains vnfH (encoding dinitrogenase reductase 2) and a ferredoxin like open reading frame (Fd). The second one includes vnfD (encoding the .alpha. subunit of dinitrogenase 2), vnfG (encoding a product similar to the .delta. subunit of dinitrogenase 2 from A. chroococcum), and vnfK (encoding the .beta. subunit of dinitrogenase 2). The 5''-flanking regions of vnfH and vnfD contain sequences similar to ntrA-dependent promoters. This gene arrangement allows independent expression of vnfH-Fd and vnfDKG. Mutant strains (CA80 and CA11.80) carrying an insertion in vnfH are still able to synthesize the .alpha. and .beta. subunits of dinitrogenase 2 when grown in N-free, Mo-deficient, V-containing medium. A strain (RP1.11) carrying a deletion-plus-insertion mutation in the vnfDGK region produced dinitrogenase reductase 2.