Details
| Original language | English |
|---|---|
| Pages (from-to) | 331-342 |
| Number of pages | 12 |
| Journal | Plant molecular biology |
| Volume | 72 |
| Issue number | 3 |
| Publication status | Published - 2010 |
| Externally published | Yes |
Abstract
Complex II plays a central role in mitochondrial metabolism as a component of both the electron transport chain and the tricarboxylic acid cycle. However, the composition and function of the plant enzyme has been elusive and differs from the well-characterised enzymes in mammals and bacteria. Herewith, we demonstrate that mitochondrial Complex II from Arabidopsis and rice differ significantly in several aspects: (1) Stability-Rice complex II in contrast to Arabidopsis is not stable when resolved by native electrophoresis and activity staining. (2) Composition-Arabidopsis complex II contains 8 subunits, only 7 of which have homologs in the rice genome. SDH 1 and 2 subunits display high levels of amino acid identity between two species, while the remainder of the subunits are not well conserved at a sequence level, indicating significant divergence. (3) Gene expression-the pairs of orthologous SDH1 and SDH2 subunits were universally expressed in both Arabidopsis and rice. The very divergent genes for SDH3 and SDH4 were co-expressed in both species, consistent with their functional co-ordination to form the membrane anchor. The plant-specific SDH5, 6 and 7 subunits with unknown functions appeared to be differentially expressed in both species. (4) Biochemical regulation -succinate-dependent O2 consumption and SDH activity of isolated Arabidopsis mitochondria were substantially stimulated by ATP, but a much more minor effect of ATP was observed for the rice enzyme. The ATP activation of succinate-dependent reduction of DCPIP in frozen-thawed and digitonin-solubilised mitochondrial samples, and with or without the uncoupler CCCP, indicate that the differential ATP effect on SDH is not via the protonmotive force but likely due to an allosteric effect on the plant SDH enzyme itself, in contrast to the enzyme in other organisms.
Keywords
- Arabidopsis, Complex II, Mitochondria, Rice, Succinate dehydrogenase
ASJC Scopus subject areas
- Agricultural and Biological Sciences(all)
- Agronomy and Crop Science
- Biochemistry, Genetics and Molecular Biology(all)
- Genetics
- Agricultural and Biological Sciences(all)
- Plant Science
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In: Plant molecular biology, Vol. 72, No. 3, 2010, p. 331-342.
Research output: Contribution to journal › Article › Research › peer review
}
TY - JOUR
T1 - Functional and composition differences between mitochondrial complex II in Arabidopsis and rice are correlated with the complex genetic history of the enzyme
AU - Huang, Shaobai
AU - Taylor, Nicolas L.
AU - Narsai, Reena
AU - Eubel, Holger
AU - Whelan, James
AU - Millar, A. Harvey
N1 - Funding information: Acknowledgments This work was supported by The Australian Research Council through the ARC Centre of Excellence in Plant Energy Biology (CE0561495) to AHM and JW, AHM is funded as an ARC Australian Professorial Fellow, NTL and HE as ARC Australian Post-doctoral Fellows. Dr. Joshua Heazlewood (Laurence Berkeley
PY - 2010
Y1 - 2010
N2 - Complex II plays a central role in mitochondrial metabolism as a component of both the electron transport chain and the tricarboxylic acid cycle. However, the composition and function of the plant enzyme has been elusive and differs from the well-characterised enzymes in mammals and bacteria. Herewith, we demonstrate that mitochondrial Complex II from Arabidopsis and rice differ significantly in several aspects: (1) Stability-Rice complex II in contrast to Arabidopsis is not stable when resolved by native electrophoresis and activity staining. (2) Composition-Arabidopsis complex II contains 8 subunits, only 7 of which have homologs in the rice genome. SDH 1 and 2 subunits display high levels of amino acid identity between two species, while the remainder of the subunits are not well conserved at a sequence level, indicating significant divergence. (3) Gene expression-the pairs of orthologous SDH1 and SDH2 subunits were universally expressed in both Arabidopsis and rice. The very divergent genes for SDH3 and SDH4 were co-expressed in both species, consistent with their functional co-ordination to form the membrane anchor. The plant-specific SDH5, 6 and 7 subunits with unknown functions appeared to be differentially expressed in both species. (4) Biochemical regulation -succinate-dependent O2 consumption and SDH activity of isolated Arabidopsis mitochondria were substantially stimulated by ATP, but a much more minor effect of ATP was observed for the rice enzyme. The ATP activation of succinate-dependent reduction of DCPIP in frozen-thawed and digitonin-solubilised mitochondrial samples, and with or without the uncoupler CCCP, indicate that the differential ATP effect on SDH is not via the protonmotive force but likely due to an allosteric effect on the plant SDH enzyme itself, in contrast to the enzyme in other organisms.
AB - Complex II plays a central role in mitochondrial metabolism as a component of both the electron transport chain and the tricarboxylic acid cycle. However, the composition and function of the plant enzyme has been elusive and differs from the well-characterised enzymes in mammals and bacteria. Herewith, we demonstrate that mitochondrial Complex II from Arabidopsis and rice differ significantly in several aspects: (1) Stability-Rice complex II in contrast to Arabidopsis is not stable when resolved by native electrophoresis and activity staining. (2) Composition-Arabidopsis complex II contains 8 subunits, only 7 of which have homologs in the rice genome. SDH 1 and 2 subunits display high levels of amino acid identity between two species, while the remainder of the subunits are not well conserved at a sequence level, indicating significant divergence. (3) Gene expression-the pairs of orthologous SDH1 and SDH2 subunits were universally expressed in both Arabidopsis and rice. The very divergent genes for SDH3 and SDH4 were co-expressed in both species, consistent with their functional co-ordination to form the membrane anchor. The plant-specific SDH5, 6 and 7 subunits with unknown functions appeared to be differentially expressed in both species. (4) Biochemical regulation -succinate-dependent O2 consumption and SDH activity of isolated Arabidopsis mitochondria were substantially stimulated by ATP, but a much more minor effect of ATP was observed for the rice enzyme. The ATP activation of succinate-dependent reduction of DCPIP in frozen-thawed and digitonin-solubilised mitochondrial samples, and with or without the uncoupler CCCP, indicate that the differential ATP effect on SDH is not via the protonmotive force but likely due to an allosteric effect on the plant SDH enzyme itself, in contrast to the enzyme in other organisms.
KW - Arabidopsis
KW - Complex II
KW - Mitochondria
KW - Rice
KW - Succinate dehydrogenase
UR - http://www.scopus.com/inward/record.url?scp=75949097168&partnerID=8YFLogxK
U2 - 10.1007/s11103-009-9573-z
DO - 10.1007/s11103-009-9573-z
M3 - Article
C2 - 19924544
AN - SCOPUS:75949097168
VL - 72
SP - 331
EP - 342
JO - Plant molecular biology
JF - Plant molecular biology
SN - 0167-4412
IS - 3
ER -