Characterization of the genes responsible for rubber degradation in Actinoplanes sp. strain OR16
Characterization of the genes responsible for rubber degradation in Actinoplanes sp. strain OR16
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DOI：
10.1007/s00253-020-10700-1
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发表时间：
2020-07-18
影响因子：
5
通讯作者：
Kasai, Daisuke
中科院分区：
文献类型：
--
作者：
Gibu, Namiko;Arata, Tomoka;Kasai, Daisuke
革兰氏阳性橡胶降解细菌游动放线菌属菌株OR 16（菌株NBRC 114529）能够在含有天然和合成橡胶作为唯一碳源和能量源的琼脂平板上生长。当该菌株在天然橡胶胶乳覆盖琼脂平板上生长时，观察到细胞周围的半透明晕圈。为了鉴定天然橡胶降解基因及其代谢的其他特征，测定了其全基因组序列。OR 16基因组全长9，293，892 bp，含有一条环状染色体（GenBank登录号为AP 019371.1），G + C含量为70.3%。基因组包含8238个蛋白质编码基因和18个rRNA基因。基因组序列的同源性搜索显示，三个基因（lcp 1，lcp 2，和lcp 3）是同源的胞外胶乳清除蛋白（LCP）的链霉菌。K30。RT-PCR分析显示lcp 1和lcp 2似乎构成一个操纵子。纯化的lcp基因产物对天然胶乳具有耗氧活性，表明所有这些基因编码的橡胶降解酶在OR 16。定量逆转录PCR分析表明，这些基因的转录诱导OR 16在天然橡胶的生长过程中。位于lcp 1和lcp 3附近的基因编码TetR/AcrR型转录调节因子，可以结合这些lcp基因的启动子区域。推测这些调控因子可能参与了lcp基因的转录调控。这些结果有力地表明，在菌株OR 16中，天然橡胶的利用需要三个lcp基因。
A Gram-positive rubber-degrading bacterium, Actinoplanes sp. strain OR16 (strain NBRC 114529), is able to grow on agar plates containing natural and synthetic rubber as the sole sources of carbon and energy. When this strain was grown on natural rubber latex overlay agar plates, translucent halos around the cells were observed. To identify the natural rubber degradation genes and other features of its metabolism, its complete genome sequence was determined. The genome of OR16 consists of 9, 293, 892 bp and comprises one circular chromosome (GenBank accession number AP019371.1) with a G + C content of 70.3%. The genome contains 8238 protein-coding and 18 rRNA genes. A homology search of the genome sequence revealed that three genes (lcp1, lcp2, and lcp3) are homologous to an extracellular latex-clearing protein (Lcp) of Streptomyces sp. K30. RT-PCR analysis revealed that lcp1 and lcp2 seem to constitute an operon. Purified lcp gene products have oxygen consumption activity toward natural rubber latex, suggesting that all these genes encode rubber-degrading enzymes in OR16. Quantitative reverse transcription-PCR analysis indicated that the transcription of these genes is induced during the growth of OR16 on natural rubber. The genes located adjacent to lcp1 and lcp3, which code for a TetR/AcrR-type transcriptional regulator, can bind to the promoter regions of these lcp genes. It is suggested that the putative regulators play a role in regulating the transcription of the lcp genes. These results strongly suggested that three lcp genes are required for the utilization of natural rubber in strain OR16.