Abstract
Cox11 is an intrinsic mitochondrial membrane protein essential for the assembly of an active cytochrome c oxidase complex. Cox11 is tethered to the mitochondrial inner membrane by a single transmembrane helix. Domain mapping was carried out to determine the functional segments of the Cox11 protein. The C-terminal 189 residue Cu(I)-binding domain is shown to be exposed within the mitochondrial intermembrane space. This orientation was demonstrated by the proteolytic susceptibility of a C-terminal Myc epitope tag in mitoplasts but not intact mitochondria. Fusion of the N terminus of Cox11 to the matrix ribosomal protein Rsm22 results in a functional protein capable of suppressing the respiratory defect of both Δcox11 cells and Δrsm22 cells. The functionality of the fusion protein suggests that the Cox11 N terminus projects into the matrix. The fusion of the C-terminal segment of Cox11 to Rsm22 resembles a naturally occurring fusion of Cox11 in Schizosaccharomyces pombe to a sequence homologous to the Saccharomyces cerevisiae Rsm22. Studies on a series of SCO1/COX11 chimeras reveal that the matrix domain of Cox11 lacks a specific function, whereas the Cu(I) binding/donating function requires the yeast Cox11 sequence. The Cu(I)-binding domain from human Cox11 cannot functionally replace the yeast sequence. The copper domain of Cox11 may be an important docking motif for Cox1 or a Cox1-associated protein.
| Original language | English |
|---|---|
| Pages (from-to) | 22664-22669 |
| Number of pages | 6 |
| Journal | Journal of Biological Chemistry |
| Volume | 280 |
| Issue number | 24 |
| DOIs | |
| Publication status | Published - 2005 Jun 17 |
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All Science Journal Classification (ASJC) codes
- Biochemistry
- Molecular Biology
- Cell Biology
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Functional analysis of the domains in Cox11. / Carr, Heather S.; Maxfield, Andrew B.; Horng, Yih Chern; Winge, Dennis R.
In: Journal of Biological Chemistry, Vol. 280, No. 24, 17.06.2005, p. 22664-22669.Research output: Contribution to journal › Article
TY - JOUR
T1 - Functional analysis of the domains in Cox11
AU - Carr, Heather S.
AU - Maxfield, Andrew B.
AU - Horng, Yih Chern
AU - Winge, Dennis R.
PY - 2005/6/17
Y1 - 2005/6/17
N2 - Cox11 is an intrinsic mitochondrial membrane protein essential for the assembly of an active cytochrome c oxidase complex. Cox11 is tethered to the mitochondrial inner membrane by a single transmembrane helix. Domain mapping was carried out to determine the functional segments of the Cox11 protein. The C-terminal 189 residue Cu(I)-binding domain is shown to be exposed within the mitochondrial intermembrane space. This orientation was demonstrated by the proteolytic susceptibility of a C-terminal Myc epitope tag in mitoplasts but not intact mitochondria. Fusion of the N terminus of Cox11 to the matrix ribosomal protein Rsm22 results in a functional protein capable of suppressing the respiratory defect of both Δcox11 cells and Δrsm22 cells. The functionality of the fusion protein suggests that the Cox11 N terminus projects into the matrix. The fusion of the C-terminal segment of Cox11 to Rsm22 resembles a naturally occurring fusion of Cox11 in Schizosaccharomyces pombe to a sequence homologous to the Saccharomyces cerevisiae Rsm22. Studies on a series of SCO1/COX11 chimeras reveal that the matrix domain of Cox11 lacks a specific function, whereas the Cu(I) binding/donating function requires the yeast Cox11 sequence. The Cu(I)-binding domain from human Cox11 cannot functionally replace the yeast sequence. The copper domain of Cox11 may be an important docking motif for Cox1 or a Cox1-associated protein.
AB - Cox11 is an intrinsic mitochondrial membrane protein essential for the assembly of an active cytochrome c oxidase complex. Cox11 is tethered to the mitochondrial inner membrane by a single transmembrane helix. Domain mapping was carried out to determine the functional segments of the Cox11 protein. The C-terminal 189 residue Cu(I)-binding domain is shown to be exposed within the mitochondrial intermembrane space. This orientation was demonstrated by the proteolytic susceptibility of a C-terminal Myc epitope tag in mitoplasts but not intact mitochondria. Fusion of the N terminus of Cox11 to the matrix ribosomal protein Rsm22 results in a functional protein capable of suppressing the respiratory defect of both Δcox11 cells and Δrsm22 cells. The functionality of the fusion protein suggests that the Cox11 N terminus projects into the matrix. The fusion of the C-terminal segment of Cox11 to Rsm22 resembles a naturally occurring fusion of Cox11 in Schizosaccharomyces pombe to a sequence homologous to the Saccharomyces cerevisiae Rsm22. Studies on a series of SCO1/COX11 chimeras reveal that the matrix domain of Cox11 lacks a specific function, whereas the Cu(I) binding/donating function requires the yeast Cox11 sequence. The Cu(I)-binding domain from human Cox11 cannot functionally replace the yeast sequence. The copper domain of Cox11 may be an important docking motif for Cox1 or a Cox1-associated protein.
UR - http://www.scopus.com/inward/record.url?scp=20744438924&partnerID=8YFLogxK
UR - http://www.scopus.com/inward/citedby.url?scp=20744438924&partnerID=8YFLogxK
U2 - 10.1074/jbc.M414077200
DO - 10.1074/jbc.M414077200
M3 - Article
C2 - 15840584
AN - SCOPUS:20744438924
VL - 280
SP - 22664
EP - 22669
JO - Journal of Biological Chemistry
JF - Journal of Biological Chemistry
SN - 0021-9258
IS - 24
ER -