ISSN:
0006-3592
Keywords:
cytochrome o
;
globin function
;
Vitreoscilla hemoglobin
;
oxygen starvation
;
Chemistry
;
Biochemistry and Biotechnology
Source:
Wiley InterScience Backfile Collection 1832-2000
Topics:
Biology
,
Process Engineering, Biotechnology, Nutrition Technology
Notes:
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. © 1996 John Wiley & Sons, Inc.
Additional Material:
3 Ill.
Type of Medium:
Electronic Resource
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