title: Gene Arrangements in Expression Vector Affect 3-Hydroxypropionic Acid Production in Klebsiella pneumoniae.
abstract: Biosynthesis of 3-hydroxypropionic acid (3-HP) typically involves two sequential reactions catalyzed by glycerol dehydratase (DhaB) and aldehyde dehydrogenase (AldH). Although plasmid-dependent over-expression of the two enzymes is common, systematic investigation of gene arrangement in vector has not been reported. Here we show that gene arrangements have a noticeable influence on 3-HP production. Using Klebsiella pneumoniae as a host, three AldH-coding genes: ald4 from Saccharomyces cerevisiae, aldh from Escherichia coli, and puuC from host K. pneumoniae, were respectively ligated to dhaB. The recombinant Kp/pET-pk-ald4-dhaB (Kp refers to as K. pneumoniae, pk is a native promoter) produced the highest yield of 3-HP in comparison to both Kp/pET-pk-dhaB-ald4 and Kp/pET-pk-dhaB-pk-ald4, suggesting that the preferential expression of AldH can increase 3-HP production. Additionally, when different AldH-coding genes were respectively ligated downstream of dhaB, the recombinant Kp/pET-pk-dhaB-puuC produced more 3-HP than that by Kp/pET-pk-dhaB-aldh or Kp/pET-pk-dhaB-ald4, implying the intrinsic compatibility of native gene puuC with its host. These findings indicate the applicability of native AldH-coding gene and provide insights into strategies for metabolic engineering of multiple genes.
authors.affiliation: College of Life Science and Technology, Beijing University of Chemical Technology, Beijing, 100029 People's Republic of China.
authors.forename: Ying
authors.initials: Y
authors.lastname: Li
authors.affiliation: Biochemical Engineering College of Beijing Union University, Beijing, 100023 People's Republic of China.
authors.forename: Xizhen
authors.initials: X
authors.lastname: Ge
authors.affiliation: College of Life Science and Technology, Beijing University of Chemical Technology, Beijing, 100029 People's Republic of China.
authors.forename: Pingfang
authors.initials: P
authors.lastname: Tian
keywords: 3-Hydroxypropionic acid; Aldehyde dehydrogenase; Gene arrangement; Glycerol dehydratase; Klebsiella pneumoniae