title: Understanding the function of bacterial and eukaryotic thiolases II by integrating evolutionary and functional approaches.
abstract: Acetoacetyl-CoA thiolase (EC 2.3.1.9), commonly named thiolase II, condenses two molecules of acetyl-CoA to give acetoacetyl-CoA and CoA. This enzyme acts in anabolic processes as the first step in the biosynthesis of isoprenoids and polyhydroxybutyrate in eukaryotes and bacteria, respectively. We have recently reported the evolutionary and functional equivalence of these enzymes, suggesting that thiolase II could be the rate limiting enzyme in these pathways and presented evidence indicating that this enzyme modulates the availability of reducing equivalents during abiotic stress adaptation in bacteria and plants. However, these results are not sufficient to clarify why thiolase II was evolutionary selected as a critical enzyme in the production of antioxidant compounds. Regarding this intriguing topic, we propose that thiolase II could sense changes in the acetyl-CoA/CoA ratio induced by the inhibition of the tricarboxylic acid cycle under abiotic stress. Thus, the high level of evolutionary and functional constraint of thiolase II may be due to the connection of this enzyme with an ancient and conserved metabolic route.
authors.affiliation: Consejo Nacional de Investigaciones Científicas y Técnicas (CONICET), Avda. Rivadavia 1917, C1033AAJ Cuidad Autónoma de Buenos Aires, Argentina.
authors.forename: Ana Romina
authors.initials: AR
authors.lastname: Fox
authors.forename: Gabriela
authors.initials: G
authors.lastname: Soto
authors.forename: Matteo
authors.initials: M
authors.lastname: Mozzicafreddo
authors.forename: Araceli Nora
authors.initials: AN
authors.lastname: Garcia
authors.forename: Massimiliano
authors.initials: M
authors.lastname: Cuccioloni
authors.forename: Mauro
authors.initials: M
authors.lastname: Angeletti
authors.forename: Juan Carlos
authors.initials: JC
authors.lastname: Salerno
authors.forename: Nicolás Daniel
authors.initials: ND
authors.lastname: Ayub
mesh_terms: D000101:Acetyl-CoA C-Acetyltransferase / Q000235:genetics / Q000378:metabolism*; D001419:Bacteria / Q000201:enzymology*; D005075:Biological Evolution; D005057:Eukaryotic Cells / Q000201:enzymology*
chemical_list: D000101:Acetyl-CoA C-Acetyltransferase
keywords: 1-deoxy-d-xylulose-5-phosphate synthase; 3-hydroxy-3-methylglutaryl-CoA; 3-hydroxy-3-methylglutaryl-CoA reductase; AACT; ABC; Acetoacetyl-CoA thiolase; Acetyl-CoA; Antioxidant compounds; CoA; DXS; HMG-CoA; HMGR; IPP; Isopentenyl diphosphate; MEP; MVA; Mevalonate; NJ; Neighbor-joining; PCR; PHB; PPP; Pentose phosphate pathway; Plastidic methylerythritol phosphate; Polyhydroxybutyrate; Polyhydroxybutyrate biosynthesis; Polymerase chain reaction; TCA; Thiolase II; Tricarboxylic acid; Tricarboxylic acid cycle