Identification of the Polyhydroxyalkanoate (PHA)-Specific Acetoacetyl Coenzyme A Reductase among Multiple FabG Paralogs in Haloarcula hispanica and Reconstruction of the PHA Biosynthetic Pathway in Haloferax volcanii
Identification of the Polyhydroxyalkanoate (PHA)-Specific Acetoacetyl Coenzyme A Reductase among Multiple FabG Paralogs in Haloarcula hispanica and Reconstruction of the PHA Biosynthetic Pathway in Haloferax volcanii
复制标题
西班牙Haloarcula 中多个FabG 旁系同源物中聚羟基脂肪酸酯(PHA) 特异性乙酰乙酰辅酶A 还原酶的鉴定以及Haloferax volcanii 中PHA 生物合成途径的重建
DOI：
10.1128/aem.00938-09
复制
发表时间：
2009-10-01
影响因子：
4.4
通讯作者：
Xiang, Hua
中科院分区：
文献类型：
--
作者：
Han, Jing;Lu, Qiuhe;Xiang, Hua
ABSTRACT
Genome-wide analysis has revealed abundant FabG (β-ketoacyl-ACP reductase) paralogs, with uncharacterized biological functions, in several halophilic archaea. In this study, we identified for the first time that the
fabG1
gene, but not the other five
fabG
paralogs, encodes the polyhydroxyalkanoate (PHA)-specific acetoacetyl coenzyme A (acetoacetyl-CoA) reductase in
Haloarcula hispanica
. Although all of the paralogous
fabG
genes were actively transcribed, only disruption or knockout of
fabG1
abolished PHA synthesis, and complementation of the Δ
fabG1
mutant with the
fabG1
gene restored both PHA synthesis capability and the NADPH-dependent acetoacetyl-CoA reductase activity. In addition, heterologous coexpression of the PHA synthase genes (
phaEC
) together with
fabG1
, but not its five paralogs, reconstructed the PHA biosynthetic pathway in
Haloferax volcanii
, a PHA-defective haloarchaeon. Taken together, our results indicate that FabG1 in
H. hispanica
, and possibly its counterpart in
Haloarcula marismortui
, has evolved the distinct function of supplying precursors for PHA biosynthesis, like PhaB in bacteria. Hence, we suggest the renaming of FabG1 in both genomes as PhaB, the PHA-specific acetoacetyl-CoA reductase of halophilic archaea.
