Disease relevance of sdhC

• Gene products of sdhC and sdhD are small hydrophobic subunits that anchor the hydrophilic catalytic subunits (flavoprotein and iron-sulfur protein) to the cytoplasmic membrane and are believed to be the components of cytochrome b556 in E. coli complex II [1].
• QPs1 has a higher sequence similarity to the sdhC peptide of Escherichia coli than to the sdhC peptide (cytochrome b558) of Bacillus subtilis [2].

High impact information on sdhC

• An increase in cytochrome b content was found in the membrane when sdhD was introduced, while the cytochrome b content did not change when sdhC was introduced [1].
• To understand how ArcA participates in the anaerobic repression of sdhCDAB expression, a family of sdhC-lacZ fusions was constructed and analysed in vivo [3].
• Lastly, the Fnr-dependent control of sdhCDAB gene expression was shown to occur independently of the ArcA and to require DNA sequences near the start of sdhC transcription [3].
• A base-pair exchange of G to A in the ribosome-binding sequence of sdhC was found to reduce cytochrome b-558 translation about tenfold in B. subtilis, whereas the mutation had no effect on translation in E. coli [4].
• From the result of steady-state kinetics of cytochromes in the membrane and E'm values of purified cytochromes, we propose a branched arrangement of the late exponential phase of aerobic growth, as shown in Fig. 10. Cytochrome b-556 is reduced by several dehydrogenases and the gene for this cytochrome (cybA) is located in the sdh gene cluster [5].

Biological context of sdhC

• The sdhC (384 base-pairs) and sdhD (342 base-pairs) structural genes encode two strongly hydrophobic proteins of Mr 14167 and 12792 respectively [6].
• Lastly, sdhC-lacZ expression was shown to vary with the cell growth rate during aerobic and anaerobic conditions [7].
• There is little homology between the B. subtilis cytochrome b558 and cytochrome b of mitochondrial complex III from different organisms or between cytochrome b558 and the hydrophobic sdhC and sdhD peptides of the Escherichia coli sdh operon [8].

Associations of sdhC with chemical compounds

• In contrast, significantly higher amounts of cytochrome b556 were expressed in the membrane when sdhC and sdhD genes were both present, and the catalytic portion was found to be localized in the membrane with succinate-ubiquitnone oxidoreductase and succinate oxidase activities [1].
• Together with data showing correlation between the intracellular cAMP concentrations and the sdhC-lacZ expression levels in several mutants and wild type, in vitro transcription assays suggest that the decrease in the CRP.cAMP level in the presence of glucose is the major determinant of the glucose repression of the sdhCDAB operon [9].

Other interactions of sdhC

• Iron and haem availability affected sdhC-lacZ expression by two- to three-fold [7].

References