Stein L Y, Sayavedra-Soto L A, Hommes N G, Arp D J
Laboratory for Nitrogen Fixation Research, Department of Botany and Plant Pathology, Oregon State University, 2082 Cordley, Corvallis, OR 97331-2902, USA.
FEMS Microbiol Lett. 2000 Nov 15;192(2):163-8. doi: 10.1111/j.1574-6968.2000.tb09376.x.
Nitrosomonas europaea contains two nearly identical copies of the operon, amoCAB, which encodes the ammonia monooxygenase (AMO) enzyme. Cells of N. europaea containing single mutations in either amoA or amoB gene copies were incubated in ammonium both prior to and after exposure to acetylene or light. For each strain, the O(2) consumption rates and amounts of AmoA polypeptide, the active site-containing subunit of AMO, produced in each strain were determined. Strains carrying a mutation in either the amoA(2) or amoB(2) genes responded similarly to wild-type cells, but the strains carrying mutations in the amoA(1) or amoB(1) genes responded differently from the wild-type, or from each other. These results suggest that the copies of amoA and amoB are differentially regulated upon exposure to different external stimuli.
欧洲亚硝化单胞菌含有操纵子amoCAB的两个几乎相同的拷贝，该操纵子编码氨单加氧酶（AMO）。在暴露于乙炔或光照之前和之后，将在amoA或amoB基因拷贝中含有单突变的欧洲亚硝化单胞菌细胞在铵中培养。对于每个菌株，测定了每个菌株的O₂消耗速率以及产生的AmoA多肽（AMO的含活性位点的亚基）的量。在amoA(2)或amoB(2)基因中携带突变的菌株与野生型细胞的反应相似，但在amoA(1)或amoB(1)基因中携带突变的菌株与野生型或彼此之间的反应不同。这些结果表明，amoA和amoB的拷贝在暴露于不同外部刺激时受到不同的调节。
