Characterization of acetyl-CoA and propionyl-CoA carboxylases encoded by Leptospira interrogans serovar Lai: an initial biochemical study for leptospiral gluconeogenesis via anaplerotic CO2 assimilation
Publication in refereed journal



摘要Leptospira interrogans is the causative agent of leptospirosis. The in vitro growth of L. interrogans requires CO2 and a partial 3-hydroxypropionate pathway involving two acyl-CoA carboxylases was suggested by genomic analysis to assimilate CO2. Either set of the candidate genes heterologously co-expressed in Escherichia coli was able to demonstrate both acetyl-CoA carboxylase (ACC) and propionyl-CoA carboxylase (PCC) activities. The tri-subunit holoenzyme (LA_2736-LA_2735 and LA_3803), although failed to be purified, was designated ACC based on its substrate preference toward acetyl-CoA. The partially purified bi-subunit holoenzyme (LA_2432-LA_2433) has a considerably higher activity against propionyl-CoA as the substrate than that of acetyl-CoA, and thus, designated PCC. Native polyacrylamide gel electrophoresis indicated that this PCC has a molecular mass of around 669 kDa, suggesting an (44) quaternary structure and both structural homology modeling and site-directed mutagenesis analysis of its carboxyltransferase subunit (LA_2433) indicated that the A431 residue located at the bottom of the putative substrate binding pocket may play an important role in substrate specificity determination. Both transcriptomic and proteomic data indicated that enzymes involved in the suggested partial 3-hydroxypropionate pathway were expressed in vivo in addition to ACC/PCC and the homologous genes in genomes of other Leptospira species were re-annotated accordingly. However, as the in vitro detected specific activity of ACC in the crude cell extract was too low to account for the growth of the bacterium in EllinghausenMcCulloughJohnsonHarris minimal medium, further systematic analysis is required to unveil the mechanism of gluconeogenesis via anaplerotic CO2 assimilation in Leptospira species.
著者Peng NQ, Zhong Y, Zhang Q, Zheng MY, Zhao W, Jiang HL, Yang C, Guo XK, Zhao GP
期刊名稱Acta Biochimica et Biophysica Sinica
頁次692 - 702
關鍵詞acetyl-CoA carboxylase; CO2 assimilation; Leptospira interrogans; propionyl-CoA carboxylase
Web of Science 學科類別Biochemistry & Molecular Biology; BIOCHEMISTRY & MOLECULAR BIOLOGY; Biophysics; BIOPHYSICS

上次更新時間 2020-25-10 於 01:24