PMID- 25241981
OWN - NLM
STAT- MEDLINE
DCOM- 20150224
LR  - 20211021
IS  - 1470-8728 (Electronic)
IS  - 0264-6021 (Print)
IS  - 0264-6021 (Linking)
VI  - 464
IP  - 3
DP  - 2014 Dec 15
TI  - Comparisons of subunit 5A and 5B isoenzymes of yeast cytochrome c oxidase.
PG  - 335-42
LID - 10.1042/BJ20140732 [doi]
AB  - Subunit 5 of Saccharomyces cerevisiae cytochrome c oxidase (CcO) is essential for 
      assembly and has two isoforms, 5A and 5B. 5A is expressed under normoxic 
      conditions, whereas 5B is expressed at very low oxygen tensions. As a 
      consequence, COX5A-deleted strains (Deltacox5A) have no or only low levels of CcO 
      under normoxic conditions rendering them respiratory deficient. Previous studies 
      have reported that respiratory growth could be restored by combining Deltacox5A with 
      mutations of ROX1 that encodes a repressor of COX5B expression. In these mutants, 
      5B isoenzyme expression level was 30-50% of wild-type (5A isoenzyme) and 
      exhibited a maximum catalytic activity up to 3-fold faster than that of 5A 
      isoenzyme. To investigate the origin of this effect, we constructed a mutant 
      strain in which COX5B replaced COX5A downstream of the COX5A promoter. This 
      strain expressed wild-type levels of the 5B isoenzyme, without the complication 
      of additional effects caused by mutation of ROX1. When produced this way, the 
      isoenzymes displayed no significant differences in their maximum catalytic 
      activities or in their affinities for oxygen or cytochrome c. Hence the elevated 
      activity of the 5B isoenzyme in the rox1 mutant is not caused simply by exchange 
      of isoforms and must arise from an additional effect that remains to be resolved.
FAU - Dodia, Raksha
AU  - Dodia R
AD  - *Institute of Structural and Molecular Biology, University College London, Gower 
      Street, London WC1E 6BT, U.K.
FAU - Meunier, Brigitte
AU  - Meunier B
AD  - daggerCentre de Genetique Moleculaire du CNRS, UPR 3404, avenue de la Terrasse, 
      Gif-sur-Yvette Cedex 91198, France.
FAU - Kay, Christopher W M
AU  - Kay CW
AD  - *Institute of Structural and Molecular Biology, University College London, Gower 
      Street, London WC1E 6BT, U.K.
FAU - Rich, Peter R
AU  - Rich PR
AD  - *Institute of Structural and Molecular Biology, University College London, Gower 
      Street, London WC1E 6BT, U.K.
LA  - eng
GR  - BB/F016948/1/Biotechnology and Biological Sciences Research Council/United 
      Kingdom
PT  - Comparative Study
PT  - Journal Article
PT  - Research Support, Non-U.S. Gov't
PL  - England
TA  - Biochem J
JT  - The Biochemical journal
JID - 2984726R
RN  - 0 (Isoenzymes)
RN  - 0 (Protein Subunits)
RN  - 0 (Saccharomyces cerevisiae Proteins)
RN  - EC 1.9.3.1 (Cox5a protein, S cerevisiae)
RN  - EC 1.9.3.1 (Cox5b protein, S cerevisiae)
RN  - EC 1.9.3.1 (Electron Transport Complex IV)
RN  - S88TT14065 (Oxygen)
SB  - IM
MH  - Animals
MH  - Electron Transport Complex IV/chemistry/genetics/*metabolism
MH  - Gene Expression Regulation, Enzymologic
MH  - Horses
MH  - Isoenzymes
MH  - Kinetics
MH  - Oxygen/metabolism
MH  - Protein Subunits
MH  - Saccharomyces cerevisiae/*enzymology/genetics/growth & development
MH  - Saccharomyces cerevisiae Proteins/chemistry/genetics/*metabolism
PMC - PMC4255728
EDAT- 2014/09/23 06:00
MHDA- 2015/02/25 06:00
PMCR- 2014/12/05
CRDT- 2014/09/23 06:00
PHST- 2014/09/23 06:00 [entrez]
PHST- 2014/09/23 06:00 [pubmed]
PHST- 2015/02/25 06:00 [medline]
PHST- 2014/12/05 00:00 [pmc-release]
AID - BJ20140732 [pii]
AID - 10.1042/BJ20140732 [doi]
PST - ppublish
SO  - Biochem J. 2014 Dec 15;464(3):335-42. doi: 10.1042/BJ20140732.