Intracellular expression of Vitreoscilla hemoglobin modifies microaerobic Escherichia coli metabolism through elevated concentration and specific activity of cytochrome o

• Published in: Biotechnology and bioengineering 2002-09, Vol.79 (5), p.558-567
• Main Authors: Tsai, Philip S., Nägeli, Michael, Bailey, James E.
• Format: Article
• Language: English
• Subjects: Aerobiosis; Bacterial Proteins - genetics; Bacterial Proteins - metabolism; Biological and medical sciences; Bioreactors; Biotechnology; Cell Respiration; Cells, Cultured; Cloning, Molecular; Cytochrome b Group; Cytochrome d Group - genetics; Cytochrome d Group - metabolism; cytochrome o; Cytochromes - genetics; Cytochromes - metabolism; Electron Transport Chain Complex Proteins; Electron Transport Complex IV - metabolism; Energy Metabolism; Escherichia coli - classification; Escherichia coli - genetics; Escherichia coli - metabolism; Escherichia coli Proteins; Fundamental and applied biological sciences. Psychology; Gene Expression Regulation, Bacterial - physiology; globin function; Hemoglobins - genetics; Hemoglobins - metabolism; Methods. Procedures. Technologies; Microbial engineering. Fermentation and microbial culture technology; Oxidation-Reduction; Oxidoreductases - metabolism; Oxygen - metabolism; Oxygen Consumption; oxygen starvation; Recombinant Proteins - metabolism; Sensitivity and Specificity; Species Specificity; Truncated Hemoglobins; Vitreoscilla hemoglobin
• ISSN: 0006-3592; 1097-0290
• DOI: 10.1002/bit.10440

The function of the reversible oxygen‐binding hemoprotein from Vitreoscilla (VHb), which enhances oxygen‐limited cell growth and recombinant protein production when functionally expressed in Escherichia coli, was investigated in wild‐type E. coli and in E. coli mutants lacking one of the two terminal oxidases, cytochrome o complex (aerobic terminal oxidase, Cyo) or cytochrome d complex (microaerobic terminal oxidase, Cyd). Deconvolution of VHb, cytochrome o, and cytochrome d bands from in vivo absorption spectra revealed a 5‐fold enhancement in cytochrome o content and a 1.5‐fold increment in cytochrome d by VHb under microaerobic environments (dissolved oxygen less than 2% air saturation). Based upon oxygen uptake kinetics measurements of these mutants, the apparent oxygen affinity of the Cyo+, Cyd− E. coli was increased in the presence of VHb, but no difference in the apparent Km was observed for the Cyo−, Cyd+ strain. Results suggest that the expression of VHb in E. coli increases the level and activity of terminal oxidases and thereby improves the efficiency of microaerobic respiration and growth. © 2002 Wiley Periodicals, Inc. Biotechnol Bioeng 79: 558–567, 2002.