Open AccessRalstonia solanacearum RSp0194 Encodes a Novel 3-Keto-Acyl Carrier Protein Synthase III
Author(s) -
Yahui Mao,
Jincheng Ma,
Ling Feng,
Zhe Hu,
Haihong Wang
Publication year - 2015
Publication title -
plos one
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.99
H-Index - 332
ISSN - 1932-6203
DOI - 10.1371/journal.pone.0136261
Subject(s) - ralstonia solanacearum , acyl carrier protein , ralstonia , fatty acid synthesis , mutant , biochemistry , fatty acid synthase , biology , fatty acid , biosynthesis , bacterial wilt , bacteria , gene , microbiology and biotechnology , genetics
Fatty acid synthesis (FAS), a primary metabolic pathway, is essential for survival of bacteria. Ralstonia solanacearum , a β-proteobacteria member, causes a bacterial wilt affecting more than 200 plant species, including many economically important plants. However, thus far, the fatty acid biosynthesis pathway of R . solanacearum has not been well studied. In this study, we characterized two forms of 3-keto-ACP synthase III, RsFabH and RsFabW, in R . solanacearum . RsFabH, the homologue of Escherichia coli FabH, encoded by the chromosomal RSc1050 gene, catalyzes the condensation of acetyl-CoA with malonyl-ACP in the initiation steps of fatty acid biosynthesis in vitro . The RsfabH mutant lost de novo fatty acid synthetic ability, and grows in medium containing free fatty acids. RsFabW, a homologue of Pseudomonas aeruginosa PA3286, encoded by a megaplasmid gene, RSp0194 , condenses acyl-CoA (C 2 -CoA to C 10 -CoA) with malonyl-ACP to produce 3-keto-acyl-ACP in vitro . Although the RsfabW mutant was viable, RsfabW was responsible for RsfabH mutant growth on medium containing free fatty acids. Our results also showed that RsFabW could condense acyl-ACP (C 4 -ACP to C 8 -ACP) with malonyl-ACP, to produce 3-keto-acyl-ACP in vitro , which implies that RsFabW plays a special role in fatty acid synthesis of R . solanacearum . All of these data confirm that R . solanacearum not only utilizes acetyl-CoA, but also, utilizes medium-chain acyl-CoAs or acyl-ACPs as primers to initiate fatty acid synthesis.