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. Author manuscript; available in PMC: 2013 Sep 18.
Published in final edited form as: Biochemistry. 2012 Sep 4;51(37):7290–7296. doi: 10.1021/bi3006847

Table 2. Characteristics of wild type and mutant cbb3-type oxygen reductases.

Subunit Strain mutant Activity
(% WT)		 [C]/[B]
ratio		 Ca/Cu 5(Ca/Fe)
CcoN R. sphaeroides WT 1001 1.5 2.4±0.3
(n = 3)		 1.44±0.5
(n = 3)
R. sphaeroides E180D <1 1.72 0 (n = 1)
R. sphaeroides E180Q 1 1.62 0 (n = 1)
R. sphaeroides E180G <1 2
R. sphaeroides E183D 1 1.62 0 (n = 1)
R. sphaeroides E183Q 7 1.5 1.92±0.34
(n = 3)		 1.13±0.23
(n = 3)
R. sphaeroides E183G 1 4
V. cholerae WT 1001 1.9 1.82±0.05
(n = 7)		 1.11±0.2
(n = 7)
V. cholerae E126D 2 1.8
V. cholerae E126Q <1 1.2 0.55±0.33
(n = 7)
V. cholerae E126G <1 1.2
V. cholerae E129D 11 1.3
V. cholerae E129Q 18 1.7 0.63±0.4
(n = 8)
V. cholerae E129G 2 1.8
V. cholerae E129A 2 1.5
CcoO R. sphaeroides S105T <1
R. sphaeroides S105A <1
R. sphaeroides S105G <1
1

The activities of the R. sphaeroides and V. cholerae cbb3-type oxygen reductases were 800 e−/sec and 500 e−/sec, respectively. See Methods section for details.

2

For these mutants, the low spin heme b component of the oxidase, though present, was not reduced by dithionite in the assembled enzyme.