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.
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.
Höschle
Birgit
B
Institut für Mikrobiologie, Universität Stuttgart, Allmandring 31, 70550 Stuttgart, Germany.
Gnau
Volker
V
Universität Tübingen, Tübingen, Germany.
Jendrossek
Dieter
D
Institut für Mikrobiologie, Universität Stuttgart, Allmandring 31, 70550 Stuttgart, Germany.
D000080462:Acyclic Monoterpenes; D001426:Bacterial Proteins / Q000235:genetics / Q000378:metabolism; D001710:Biotin / Q000378:metabolism; D019735:Carbon-Carbon Ligases / Q000235:genetics / Q000378:metabolism*; D003470:Culture Media; D045782:Hemiterpenes; D007930:Leucine / Q000737:chemistry / Q000378:metabolism*; D039821:Monoterpenes / Q000378:metabolism; D005810:Multigene Family; D010421:Pentanoic Acids / Q000737:chemistry / Q000378:metabolism*; D011550:Pseudomonas aeruginosa / Q000201:enzymology* / Q000235:genetics / Q000254:growth & development; D013729:Terpenes / Q000737:chemistry / Q000378:metabolism*
D000080462:Acyclic Monoterpenes; D001426:Bacterial Proteins; D003470:Culture Media; D045782:Hemiterpenes; D039821:Monoterpenes; D010421:Pentanoic Acids; D013729:Terpenes; C008216:isovaleric acid; D001710:Biotin; D019735:Carbon-Carbon Ligases; C021573:methylcrotonoyl-CoA carboxylase; C020566:geranoyl-CoA carboxylase; D007930:Leucine; C007078:citronellol