Delawary Mina, Ohtsubo Yoshiyuki, Ohta Akinori
Department of Biotechnology, University of Tokyo, Japan.
Biosci Biotechnol Biochem. 2003 Sep;67(9):1970-5. doi: 10.1271/bbb.67.1970.
The bph operon of Pseudomonas sp. KKS102 is constituted of 11 bph genes which encode enzymes for biphenyl assimilation. Growth of a mutant in which a large part of the bph operon was deleted was inhibited by biphenyl in a concentration-dependent manner. We constructed a series of bph operon deletion mutants and tested for their biphenyl sensitivity. Growth inhibition by biphenyl was more prominent with the mutants defective in bphA1, bphB, bphC, and bphD, which were clustered in the bph operon and working in the early stage of the biphenyl degradation. The mutant defective in bphE, which was working at the late stage and forming a different cluster from the early stage genes, was not much inhibited by biphenyl. These indicate that biphenyl is detoxified by enzymes which function in the early stage of biphenyl assimilation and thus detoxification of substrates as well as energy acquisition could have played an important role in the evolution of the KKS102 bph operon.
假单胞菌属KKS102的bph操纵子由11个bph基因组成，这些基因编码用于联苯同化的酶。bph操纵子大部分被删除的突变体的生长受到联苯的浓度依赖性抑制。我们构建了一系列bph操纵子缺失突变体，并测试了它们对联苯的敏感性。在bphA1、bphB、bphC和bphD有缺陷的突变体中，联苯对生长的抑制更为显著，这些基因聚集在bph操纵子中，并在联苯降解的早期起作用。在后期起作用且与早期基因形成不同簇的bphE有缺陷的突变体，对联苯的抑制作用不大。这些表明联苯通过在联苯同化早期起作用的酶进行解毒，因此底物的解毒以及能量获取可能在KKS102 bph操纵子的进化中发挥了重要作用。
