The Vitreoscilla hemoglobin gene: Molecular cloning, nucleotide sequence and genetic expression in Escherichia coli

Abstract

Vitreoscilla hemoglobin is involved in oxygen metabolism of this bacterium, possibly in an unusual role for a microbe. We have isolated the Vitreoscilla hemoglobin structural gene from a pUC19 genomic library using mixed oligodeoxy-nucleotide probes based on the reported amino acid sequence of the protein. The gene is expressed in Escherichia coli from its natural promoter as a major cellular protein. The nucleotide sequence, which is in complete agreement with the known amino acid sequence of the protein, suggests the existence of promoter and ribosome binding sites with a high degree of homology to consensus E. coli upstream sequences. In the case of at least some amino acids, a codon usage bias can be detected which is different from the biased codon usage pattern in E. coli. The downstream sequence exhibits homology with the 3' end sequences of several plant leghemoglobin genes. E. coli cells expressing the gene contain greater than fivefold more heme than controls.

Intracellular expression of Vitreoscilla hemoglobin alters Escherichia coli energy metabolism under oxygen‐limited conditions

“…Accordingly, we define an effective dissolved oxygen in the presence of VHb as the sum of dissolved oxygen (DO) and the oxygenated hemoglobin concentrations, DOe,, = DO + [VHb .04. (4) The effect of VHb on DO,, can be clearly seen from the plot of DO,,,/DO versus DO (Fig. 5).…”

“…While this pattern of regulation and the oxygen-binding properties of the molecule portend physiological function, there is no data to suggest a metabolic role for VHb in Vitreoscillu. However, cloning and expression of the gene (vhb) for VHb has enabled demonstration of a significant metabolic effect of VHb in several heterologous organisms [3,4,[8][9][10].…”

Oxygen-controlled regulation of the flavohemoglobin gene in Bacillus subtilis

“…The N termini of these proteins also showed high levels of similarity to hemoglobin-like protein from Vitreoscilla sp. (22,41). The amino acid sequence of the orf3 product showed no significant similarity to known proteins.…”

Genetic engineering of an industrial strain of Saccharopolyspora erythraea for stable expression of the Vitreoscilla haemoglobin gene (vhb)

“…(Khosla & Bailey, 1988a) can significantly improve cell growth and productivity (Khosla & IP: 168.62.10.252 On: Sun, 28 Apr 2019 05:41:32 P. B R U N K E R a n d OTHERS Bailey, 1988b). It was demonstrated that expression of vhb in Acremonium chrysogenum led to a threefold increase in cephalosporin C production (DeModena et al, 1993).…”