TY - JOUR
T1 - Potentiometric analysis of the cytochromes of an Escherichia coli mutant strain lacking the cytochrome d terminal oxidase complex
AU - Lorence, R. M.
AU - Green, G. N.
AU - Gennis, R. B.
PY - 1984
Y1 - 1984
N2 - A combination of potentiometric analysis and electrochemically poised low-temperature difference spectroscopy was used to examine a mutant strain of Escherichia coli that was previously shown by immunological criteria to be lacking the cytochrome d terminal oxidase. It was shown that this strain is missing cytochromes d, a1, and b558 and that the cytochrome composition of the mutant is similar to that of the wild-type strain grown under conditions of high aeration. The data indicate that the high-aeration branch of the respiratory chain contains two cytochrome components, b556 (midpoint potential [E(m)] = + 35 mV) and cytochrome o (E(m) = + 165 mV). The latter component binds to CO and apparently has a reduced-minus-oxidized split-α band with peaks at 555 and 562 nm. When the wild-type strain was grown under conditions of low aeration, the components of the cytochrome d terminal oxidase complex were observed: cytochrome d (E(m) = + 260 mV), cytochrome a1 (E(m) = + 150 mV) and cytochrome b558 (E(m) = + 180 mV). All cytochromes appeared to undergo simple one-electron oxidation-reduction reactions. In the absence of CO, cytochromes b558 and o have nearly the same E(m) values. In the presence of CO, the E(m) of cytochrome o is raised, thus allowing cytochromes b558 and o to be individually quantitated by potentiometric analysis when they are both present.
AB - A combination of potentiometric analysis and electrochemically poised low-temperature difference spectroscopy was used to examine a mutant strain of Escherichia coli that was previously shown by immunological criteria to be lacking the cytochrome d terminal oxidase. It was shown that this strain is missing cytochromes d, a1, and b558 and that the cytochrome composition of the mutant is similar to that of the wild-type strain grown under conditions of high aeration. The data indicate that the high-aeration branch of the respiratory chain contains two cytochrome components, b556 (midpoint potential [E(m)] = + 35 mV) and cytochrome o (E(m) = + 165 mV). The latter component binds to CO and apparently has a reduced-minus-oxidized split-α band with peaks at 555 and 562 nm. When the wild-type strain was grown under conditions of low aeration, the components of the cytochrome d terminal oxidase complex were observed: cytochrome d (E(m) = + 260 mV), cytochrome a1 (E(m) = + 150 mV) and cytochrome b558 (E(m) = + 180 mV). All cytochromes appeared to undergo simple one-electron oxidation-reduction reactions. In the absence of CO, cytochromes b558 and o have nearly the same E(m) values. In the presence of CO, the E(m) of cytochrome o is raised, thus allowing cytochromes b558 and o to be individually quantitated by potentiometric analysis when they are both present.
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U2 - 10.1128/jb.157.1.115-121.1984
DO - 10.1128/jb.157.1.115-121.1984
M3 - Article
C2 - 6317644
AN - SCOPUS:0021362455
SN - 0021-9193
VL - 157
SP - 115
EP - 121
JO - Journal of bacteriology
JF - Journal of bacteriology
IS - 1
ER -