title: Enhancement of acid tolerance in Zymomonas mobilis by a proton-buffering peptide.
abstract: A portion of the cbpA gene from Escherichia coli K-12 encoding a 24 amino acid proton-buffering peptide (Pbp) was cloned via the shuttle vector pJB99 into E. coli JM105 and subsequently into Zymomonas mobilis CP4. Expression of Pbp was confirmed in both JM105 and CP4 by HPLC. Z. mobilis CP4 carrying pJB99-2 (Pbp) exhibited increased acid tolerance (p < 0.05) in acidified TSB (HCl [pH 3.0] or acetic acid [pH 3.5]), glycine-HCl buffer (pH 3.0), and sodium acetate-acetic acid buffer (pH 3.5) in comparison to the parent strain (CP4) and CP4 with pJB99 (control plasmid). Although the expression of Pbp influenced survival at a low pH, the minimum growth pH was unaffected. Growth of Z. mobilis in the presence of ampicillin also significantly increased acid tolerance by an unknown mechanism. Results from this study demonstrate that the production of a peptide with a high proportion of basic amino acids can contribute to protection from low pH and weak organic acids such as acetic acid.
authors.affiliation: Cellular and Molecular Biology, University of Wisconsin, 1925 Willow Drive, Madison, 53706-1187, USA.
authors.forename: David J
authors.initials: DJ
authors.lastname: Baumler
authors.forename: Kai F
authors.initials: KF
authors.lastname: Hung
authors.forename: Jeffrey L
authors.initials: JL
authors.lastname: Bose
authors.forename: Boris M
authors.initials: BM
authors.lastname: Vykhodets
authors.forename: Chorng M
authors.initials: CM
authors.lastname: Cheng
authors.forename: Kwang-Cheol
authors.initials: KC
authors.lastname: Jeong
authors.forename: Charles W
authors.initials: CW
authors.lastname: Kaspar
mesh_terms: D000595:Amino Acid Sequence; D001483:Base Sequence; D004269:DNA, Bacterial / Q000235:genetics; D048168:Escherichia coli K12 / Q000235:genetics; D029968:Escherichia coli Proteins / Q000235:genetics / Q000378:metabolism; D005798:Genes, Bacterial; D005822:Genetic Vectors; D006863:Hydrogen-Ion Concentration; D008969:Molecular Sequence Data; D010446:Peptide Fragments / Q000235:genetics / Q000378:metabolism*; D010957:Plasmids / Q000235:genetics; D011522:Protons; D014170:Transformation, Genetic; D017355:Zymomonas / Q000235:genetics / Q000254:growth & development / Q000378:metabolism*
chemical_list: C085674:CbpA protein, E coli; D004269:DNA, Bacterial; D029968:Escherichia coli Proteins; D010446:Peptide Fragments; D011522:Protons