title: Expression of double Vitreoscilla hemoglobin enhances growth and alters ribosome and tRNA levels in Escherichia coli.
abstract: In several organisms, expression of a gene encoding dimeric hemoglobin (VHb) from the obligate aerobic bacterium Vitreoscilla stercoraria has been shown to increase microaerobic cell growth and enhance oxygen-dependent cell metabolism. In an attempt to further improve these effects of VHb, a gene encoding two vhb genes connected by a short linker of six base pairs was constructed and expressed in Escherichia coli(double VHb). Escherichia coli cells expressing double VHb reached a cell density 19% higher than that of cells expressing native VHb. The protein production per cell remained constant since the increase in cell growth was accompanied by an increase in protein content by 16%. Investigation of ribosome and tRNA content revealed that cells expressing double VHb reached their maximal capacity of protein synthesis later during cultivation than cells expressing native VHb, and furthermore they reached considerably higher levels of ribosome and tRNA compared to that of the VHb-expressing cells.
authors.affiliation: Department of Pure and Applied Biochemistry, Center for Chemistry and Chemical Engineering, Lund University, Lund, Sweden.
authors.forename: Viktoria
authors.initials: V
authors.lastname: Roos
authors.forename: Charlotte I J
authors.initials: CI
authors.lastname: Andersson
authors.forename: Cecilia
authors.initials: C
authors.lastname: Arfvidsson
authors.forename: Karl-Gustav
authors.initials: KG
authors.lastname: Wahlund
authors.forename: Leif
authors.initials: L
authors.lastname: Bülow
mesh_terms: D001426:Bacterial Proteins / Q000737:chemistry / Q000235:genetics* / Q000378:metabolism; D001483:Base Sequence; D002248:Carbon Monoxide / Q000378:metabolism; D017931:DNA Primers; D004591:Electrophoresis, Polyacrylamide Gel; D004926:Escherichia coli / Q000235:genetics* / Q000254:growth & development; D006454:Hemoglobins / Q000737:chemistry / Q000235:genetics* / Q000378:metabolism; D008958:Models, Molecular; D010957:Plasmids; D012343:RNA, Transfer / Q000235:genetics / Q000378:metabolism*; D012270:Ribosomes / Q000378:metabolism*; D054793:Truncated Hemoglobins
chemical_list: D001426:Bacterial Proteins; D017931:DNA Primers; D006454:Hemoglobins; D054793:Truncated Hemoglobins; C082613:hemoglobin protein, Vitreoscilla; D002248:Carbon Monoxide; D012343:RNA, Transfer