The atu and liu clusters are involved in the catabolic pathways for acyclic monoterpenes and leucine in Pseudomonas aeruginosa
The atu and liu clusters are involved in the catabolic pathways for acyclic monoterpenes and leucine in Pseudomonas aeruginosa
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DOI：
10.1128/aem.72.3.2070-2079.2006
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发表时间：
2006-03-01
影响因子：
4.4
通讯作者：
Campos-García, J
中科院分区：
文献类型：
--
作者：
Aguilar, JA;Zavala, AN;Campos-García, J
有证据表明，铜绿假单胞菌PAO1 gnyRDBHAL簇参与非环类异戊二烯降解(A. L. Diaz-Perez， N. A. Zavala-Hernandez， C. Cervantes，和J. Campos-Garcia, Appl。环绕。B. Hoschle， V. Gnau, and D. Jendrossek，微生物学，151:3649-3656,2005)，对应于liuRABCDE集群。在PAO1基因组中发现了一个liu（亮氨酸和异戊酸利用）同源簇，该簇与香橼酸家族（AMTC）无环单萜的分解代谢有关；它被命名为atu簇（无环萜烯利用），由atuCDEF基因组成，缺乏羟甲基戊二酰辅酶A （CoA）裂解酶（HMG-CoA裂解酶）同源物。atu和liu簇的诱变表明，它们分别通过编码与香叶酰辅酶a和3-甲基巴豆酰辅酶a途径相关的酶参与AMTC和亮氨酸分解代谢。在atuF和liuD突变体中，无环单萜烯途径的中间代谢产物香橼酸和天竺葵酸积累，亮氨酸降解速率受到影响。由atuF和RuD基因编码的香叶酰辅酶a羧化酶α亚基和3-甲基丙基辅酶a羧化酶α亚基（α - mccase）均被香茅醇诱导，而亮氨酸仅诱导α - mccase亚基。香茅醛和亮氨酸也诱导了huB基因的LacZ转录融合。liuE基因编码一种可能的羟基酰基辅酶a裂解酶（可能是hmg -辅酶a裂解酶），这种酶具有双功能活性，对AMTC和亮氨酸降解都是必不可少的。由liuABCD聚簇编码的铜绿假单胞菌PAO1产物序列相似性（77.2 ~ 79.5%）高于由atuCDEF聚簇编码的PAO1产物序列相似性（41.5%）。系统发育研究表明，铜绿假单胞菌的atu簇可能是α变形菌水平转移的结果。我们的研究结果表明，atu和liu簇是参与AMTC和亮氨酸分解代谢途径的双功能操作子。
Evidence suggests that the Pseudomonas aeruginosa PAO1 gnyRDBHAL cluster, which is involved in acyclic isoprenoid degradation (A. L. Diaz-Perez, N. A. Zavala-Hernandez, C. Cervantes, and J. Campos-Garcia, Appl. Environ. Microbiol. 70:5102-5110, 2004), corresponds to the liuRABCDE cluster (B. Hoschle, V. Gnau, and D. Jendrossek, Microbiology 151:3649-3656, 2005). A liu (leucine and isovalerate utilization) homolog cluster was found in the PAO1 genome and is related to the catabolism of acyclic monoterpenes of the citronellol family (AMTC); it was named the atu cluster (acyclic terpene utilization), consisting of the atuCDEF genes and lacking the hydroxymethyl-glutaryl-coenzyme A (CoA) lyase (HMG-CoA lyase) homolog. Mutagenesis of the atu and liu clusters showed that both are involved in AMTC and leucine catabolism by encoding the enzymes related to the geranyl-CoA and the 3-methylcrotonyl-CoA pathways, respectively. Intermediary metabolites of the acyclic monoterpene pathway, citronellic and geranic acids, were accumulated, and leucine degradation rates were affected in both atuF and liuD mutants. The alpha subunit of geranyl-CoA carboxylase and the alpha subunit of 3-methylcrotonyl-CoA carboxylase (alpha-MCCase), encoded by the atuF and RuD genes, respectively, were both induced by citronellol, whereas only the alpha-MCCase subunit was induced by leucine. Both citronellol and leucine also induced a LacZ transcriptional fusion at the huB gene. The liuE gene encodes a probable hydroxy-acyl-CoA lyase (probably HMG-CoA lyase), an enzyme with bifunctional activity that is essential for both AMTC and leucine degradation. P. aeruginosa PAO1 products encoded by the liuABCD cluster showed a higher sequence similarity (77.2 to 79.5%) with the probable products of liu clusters from several Pseudomonas species than with the atuCDEF cluster from PAO1 (41.5%). Phylogenetic studies suggest that the atu cluster from P. aeruginosa could be the result of horizontal transfer from Alphaproteobacteria. Our results suggest that the atu and liu clusters are bifunctional operons involved in both the AMTC and leucine catabolic pathways.