Abstract
In this work we have investigated the effect of a pathogenic mitochondrial DNA mutation found in human colon cells, at a functional-molecular level. The mutation results in the amino-acid substitution Tyr19His in subunit I of the human CytcO and it is associated with respiratory deficiency. It was introduced into Rhodobacter sphaeroides, which carries a cytochrome c oxidase (cytochrome aa3) that serves as a model of the mitochondrial counterpart. The residue is situated in the middle of a pathway that is used to transfer substrate protons as well as protons that are pumped across the membrane. The Tyr33His (equivalent residue in the bacterial CytcO) structural variant of the enzyme was purified and its function was investigated. The results show that in the structurally altered CytcO the activity decreased due to slowed proton transfer; proton transfer from an internal proton donor, the highly-conserved Glu286, to the catalytic site was slowed by a factor of ~5, while reprotonation of the Glu from solution was slowed by a factor of ~40. In addition, in the structural variant proton pumping was completely impaired. These results are explained in terms of introduction of a barrier for proton transfer through the D pathway and changes in the coordination of water molecules surrounding the Glu286 residue. The study offers an explanation, at the molecular level, to the link between a specific amino-acid substitution and a pathogenic phenotype identified in human colon cells.
| Original language | English (US) |
|---|---|
| Pages (from-to) | 550-556 |
| Number of pages | 7 |
| Journal | Biochimica et Biophysica Acta - Bioenergetics |
| Volume | 1797 |
| Issue number | 5 |
| DOIs | |
| State | Published - May 1 2010 |
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Keywords
- Cytochrome aa
- Deficiency
- Electron transfer
- Mitochondria
- Mitochondrial disease
- MtDNA
- Respiratory chain
ASJC Scopus subject areas
- Biophysics
- Biochemistry
- Cell Biology
Cite this
A pathogenic mutation in cytochrome c oxidase results in impaired proton pumping while retaining O2-reduction activity. / Namslauer, Ida; Lee, Hyun Ju; Gennis, Robert B; Brzezinski, Peter.
In: Biochimica et Biophysica Acta - Bioenergetics, Vol. 1797, No. 5, 01.05.2010, p. 550-556.Research output: Contribution to journal › Article
}
TY - JOUR
T1 - A pathogenic mutation in cytochrome c oxidase results in impaired proton pumping while retaining O2-reduction activity
AU - Namslauer, Ida
AU - Lee, Hyun Ju
AU - Gennis, Robert B
AU - Brzezinski, Peter
PY - 2010/5/1
Y1 - 2010/5/1
N2 - In this work we have investigated the effect of a pathogenic mitochondrial DNA mutation found in human colon cells, at a functional-molecular level. The mutation results in the amino-acid substitution Tyr19His in subunit I of the human CytcO and it is associated with respiratory deficiency. It was introduced into Rhodobacter sphaeroides, which carries a cytochrome c oxidase (cytochrome aa3) that serves as a model of the mitochondrial counterpart. The residue is situated in the middle of a pathway that is used to transfer substrate protons as well as protons that are pumped across the membrane. The Tyr33His (equivalent residue in the bacterial CytcO) structural variant of the enzyme was purified and its function was investigated. The results show that in the structurally altered CytcO the activity decreased due to slowed proton transfer; proton transfer from an internal proton donor, the highly-conserved Glu286, to the catalytic site was slowed by a factor of ~5, while reprotonation of the Glu from solution was slowed by a factor of ~40. In addition, in the structural variant proton pumping was completely impaired. These results are explained in terms of introduction of a barrier for proton transfer through the D pathway and changes in the coordination of water molecules surrounding the Glu286 residue. The study offers an explanation, at the molecular level, to the link between a specific amino-acid substitution and a pathogenic phenotype identified in human colon cells.
AB - In this work we have investigated the effect of a pathogenic mitochondrial DNA mutation found in human colon cells, at a functional-molecular level. The mutation results in the amino-acid substitution Tyr19His in subunit I of the human CytcO and it is associated with respiratory deficiency. It was introduced into Rhodobacter sphaeroides, which carries a cytochrome c oxidase (cytochrome aa3) that serves as a model of the mitochondrial counterpart. The residue is situated in the middle of a pathway that is used to transfer substrate protons as well as protons that are pumped across the membrane. The Tyr33His (equivalent residue in the bacterial CytcO) structural variant of the enzyme was purified and its function was investigated. The results show that in the structurally altered CytcO the activity decreased due to slowed proton transfer; proton transfer from an internal proton donor, the highly-conserved Glu286, to the catalytic site was slowed by a factor of ~5, while reprotonation of the Glu from solution was slowed by a factor of ~40. In addition, in the structural variant proton pumping was completely impaired. These results are explained in terms of introduction of a barrier for proton transfer through the D pathway and changes in the coordination of water molecules surrounding the Glu286 residue. The study offers an explanation, at the molecular level, to the link between a specific amino-acid substitution and a pathogenic phenotype identified in human colon cells.
KW - Cytochrome aa
KW - Deficiency
KW - Electron transfer
KW - Mitochondria
KW - Mitochondrial disease
KW - MtDNA
KW - Respiratory chain
UR - http://www.scopus.com/inward/record.url?scp=77950371031&partnerID=8YFLogxK
UR - http://www.scopus.com/inward/citedby.url?scp=77950371031&partnerID=8YFLogxK
U2 - 10.1016/j.bbabio.2010.01.027
DO - 10.1016/j.bbabio.2010.01.027
M3 - Article
C2 - 20117076
AN - SCOPUS:77950371031
VL - 1797
SP - 550
EP - 556
JO - Biochimica et Biophysica Acta - Bioenergetics
JF - Biochimica et Biophysica Acta - Bioenergetics
SN - 0005-2728
IS - 5
ER -