Methylcrotonyl-CoA and geranyl-CoA carboxylases are involved in leucine/isovalerate utilization (Liu) and acyclic terpene utilization (Atu), and are encoded by liuB/liuD and atuC/atuF, in Pseudomonas aeruginosa
Methylcrotonyl-CoA and geranyl-CoA carboxylases are involved in leucine/isovalerate utilization (Liu) and acyclic terpene utilization (Atu), and are encoded by liuB/liuD and atuC/atuF, in Pseudomonas aeruginosa
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DOI：
10.1099/mic.0.28260-0
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发表时间：
2005-11-01
期刊：
影响因子：
2.8
通讯作者：
Jendrossek, D
中科院分区：
文献类型：
--
作者：
Höschle, B;Gnau, V;Jendrossek, D
铜绿假单胞菌能够在非环单萜类(香茅醇、香茅酸、香叶醇和香叶酸酯)以及其他甲基分支化合物(如亮氨酸或异戊酸酯)上生长。香茅醇(ATU，无环萜烯利用)的分解代谢途径在甲基巴豆酰-辅酶A水平上进入亮氨酸/异戊酸酯(Liu，亮氨酸和异戊酸利用)的分解代谢途径。结合途径的关键酶是香叶酰辅酶A羧基酶(GCase)和甲基巴豆酰辅酶A羧基酶(MCase)。在本研究中，异戊酸生长的细胞仅特异性地表达MCase(含生物素亚基的表观分子质量，74 kDa)，而未检测到含GCase生物素亚基(71 KDa)。香茅醇或香茅酸培养的细胞产生这两种羧基酶。通过亲和层析从粗提物中纯化生物素依赖蛋白，并通过胰酶指纹图谱分析将其归属于相应的编码基因。MCase的两个亚基对应于铜绿假单胞菌基因组数据库的LiuB/liuD(PA2014/PA2012)和atuC/atuF(PA2888/PA2891)编码的GCase亚基。这一发现与其他人报道的相反。已鉴定的基因是两个独立的基因簇[liuRABCDE(PA2011-PA2016)和atuABCDEFGH(PA2886-PA2893)]的一部分，这两个基因被认为编码了atu和Liu通路的大部分基因。
Pseudomonas aeruginosa is able to grow on acyclic monoterpenes (citronellol, citronellate, geraniol and geranylate), and on other methyl-branched compounds such as leucine or isovalerate. The catabolic pathway of citronellol (Atu, acyclic terpene utilization) enters that of leucine/isovalerate (Liu, leucine and isovalerate utilization) at the level of methylcrotonyl-CoA. Key enzymes of the combined pathways are geranyl-CoA carboxylase (GCase) and methylcrotonyl-CoA carboxylase (MCase). In this study, isovalerate-grown cells specifically expressed MCase (apparent molecular mass of the biotin-containing subunit, 74 kDa) only, and the GCase biotin-containing subunit (71 kDa) was not detected. Citronellol- or citronellate-grown cells produced both carboxylases. Biotin-dependent proteins were purified from crude extracts by avidin-affinity chromatography, and assigned to the corresponding coding genes by trypsin fingerprint analysis. The two subunits of MCase corresponded to liuB/liuD (PA2014/PA2012) of the P. aeruginosa genome database, and atuC/atuF(PA2888/PA2891) encoded GCase subunits. This finding is contrary to that reported by others. The identified genes are part of two separate gene clusters [liuRABCDE (PA2011-PA2016) and atuABCDEFGH (PA2886-PA2893)] that are thought to encode most of the genes of the Atu and Liu pathways.