Vitreoscilla hemoglobin aids respiration under hypoxic conditions in its native host.
When Vitreoscilla were grown in medium containing 60mM sodium nitrite under both normal and limited aeration conditions, the levels of Vitreoscilla hemoglobin (VHb) were decreased by greater than 90%, while the levels of the terminal respiratory oxidase, cytochrome bo, were increased 350% under normal aeration and 7-23% under limited aeration. Cytochrome function, as measured by both NADH and ubiquinol oxidases for cells grown under both conditions, increased in parallel (by 150-222% and 8-56%, respectively, for the two activities). Nitrite in the medium inhibited Vitreoscilla growth at both normal and limited aeration. The inhibition of VHb at 60mM nitrite decreased whole cell respiration to the greatest degree in stationary phase for growth in limited aeration conditions, which was the most oxygen poor condition tested. These results are consistent with the originally proposed role for VHb, as an aid to respiration under hypoxic conditions.
Chi
Pao-Yu
PY
Department of Biological, Biology Division, Illinois Institute of Technology, Chicago, IL 60616, USA.
Webster
Dale A
DA
Stark
Benjamin C
BC
D000332:Aerobiosis; D001426:Bacterial Proteins / Q000378:metabolism*; D009097:Multienzyme Complexes / Q000378:metabolism; D009247:NADH, NADPH Oxidoreductases / Q000378:metabolism; D009573:Nitrites / Q000378:metabolism; D010088:Oxidoreductases / Q000378:metabolism; D010101:Oxygen Consumption; D054793:Truncated Hemoglobins / Q000378:metabolism*; D020589:Vitreoscilla / Q000378:metabolism*
D001426:Bacterial Proteins; D009097:Multienzyme Complexes; D009573:Nitrites; D054793:Truncated Hemoglobins; C082613:hemoglobin protein, Vitreoscilla; D010088:Oxidoreductases; C432586:ubiquinol oxidase; C023107:NADH oxidase; D009247:NADH, NADPH Oxidoreductases