Abstract
Ubiquinone, coenzyme Q, plays a pivotal role in electron transport and is a target for chemotherapy against a number of eukaryotic infectious agents, including Pneumocystis carinii. Coenzyme Q10 was previously identified as the major ubiquinone homolog in P. carinii isolated and purified from rat lungs; CoQ9 was also present. In contrast, CoQ9 and CoQ8 (but not CoQ10) were detected in the lungs of uninfected rat controls. These observations suggested that the pathogen synthesizes CoQ10, and perhaps CoQ9 as well. In the present study, CoQ biosynthesis in P. carinii was examined in greater detail. Radiolabeled mevalonate, a precursor of the CoQ polyprenyl chain, was incorporated in vitro into P. carinii ubiquinones. Incorporation of radiolabeled mevalonate into P. carinii CoQ was not enhanced by treating cells with lovastatin, suggesting that the cells did not transport the drug, or that a lovastatin-insensitive pathway for de novo synthesis of isoprenoids may also function in this organism. Radiolabeled precursors of the ring moiety, including shikimic acid, p-hydroxybenzoic acid, and tyrosine were also incorporated into P. carinii CoQ. Unexpectedly, it was found that not only CoQ9 and CoQ10, but also CoQ7, and CoQ8, were metabolically radiolabeled by all the precursors tested, indicating that the organism synthesizes CoQ7, CoQ8, CoQ9, and CoQ10. Metabolic radiolabeling of ubiquinones in rat lung controls was not detected in experiments using either radioactive mevalonate or p-hydroxybenzoate. Thus the incorporations measured using purified P. carinii preparations were due to the enzymes of the organism.
| Original language | English |
|---|---|
| Pages (from-to) | 182-187 |
| Number of pages | 6 |
| Journal | Journal of Eukaryotic Microbiology |
| Volume | 48 |
| Issue number | 2 |
| Publication status | Published - 2001 Jul 31 |
| Externally published | Yes |
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Keywords
- AIDS
- High performance liquid chromatography
- Lovastatin
- Mevalonic acid
- P-hydroxybenzoic acid
- Phosphoenolpyruvate
- Shikimic acid
- Tyrosine
ASJC Scopus subject areas
- Agricultural and Biological Sciences(all)
- Agricultural and Biological Sciences (miscellaneous)
- Applied Microbiology and Biotechnology
- Microbiology
Cite this
Pneumocystis carinii f. sp. carinii synthesizes de novo four homologs of ubiquinone. / Sul, Dong Geun; Kaneshiro, E. S.
In: Journal of Eukaryotic Microbiology, Vol. 48, No. 2, 31.07.2001, p. 182-187.Research output: Contribution to journal › Article
}
TY - JOUR
T1 - Pneumocystis carinii f. sp. carinii synthesizes de novo four homologs of ubiquinone
AU - Sul, Dong Geun
AU - Kaneshiro, E. S.
PY - 2001/7/31
Y1 - 2001/7/31
N2 - Ubiquinone, coenzyme Q, plays a pivotal role in electron transport and is a target for chemotherapy against a number of eukaryotic infectious agents, including Pneumocystis carinii. Coenzyme Q10 was previously identified as the major ubiquinone homolog in P. carinii isolated and purified from rat lungs; CoQ9 was also present. In contrast, CoQ9 and CoQ8 (but not CoQ10) were detected in the lungs of uninfected rat controls. These observations suggested that the pathogen synthesizes CoQ10, and perhaps CoQ9 as well. In the present study, CoQ biosynthesis in P. carinii was examined in greater detail. Radiolabeled mevalonate, a precursor of the CoQ polyprenyl chain, was incorporated in vitro into P. carinii ubiquinones. Incorporation of radiolabeled mevalonate into P. carinii CoQ was not enhanced by treating cells with lovastatin, suggesting that the cells did not transport the drug, or that a lovastatin-insensitive pathway for de novo synthesis of isoprenoids may also function in this organism. Radiolabeled precursors of the ring moiety, including shikimic acid, p-hydroxybenzoic acid, and tyrosine were also incorporated into P. carinii CoQ. Unexpectedly, it was found that not only CoQ9 and CoQ10, but also CoQ7, and CoQ8, were metabolically radiolabeled by all the precursors tested, indicating that the organism synthesizes CoQ7, CoQ8, CoQ9, and CoQ10. Metabolic radiolabeling of ubiquinones in rat lung controls was not detected in experiments using either radioactive mevalonate or p-hydroxybenzoate. Thus the incorporations measured using purified P. carinii preparations were due to the enzymes of the organism.
AB - Ubiquinone, coenzyme Q, plays a pivotal role in electron transport and is a target for chemotherapy against a number of eukaryotic infectious agents, including Pneumocystis carinii. Coenzyme Q10 was previously identified as the major ubiquinone homolog in P. carinii isolated and purified from rat lungs; CoQ9 was also present. In contrast, CoQ9 and CoQ8 (but not CoQ10) were detected in the lungs of uninfected rat controls. These observations suggested that the pathogen synthesizes CoQ10, and perhaps CoQ9 as well. In the present study, CoQ biosynthesis in P. carinii was examined in greater detail. Radiolabeled mevalonate, a precursor of the CoQ polyprenyl chain, was incorporated in vitro into P. carinii ubiquinones. Incorporation of radiolabeled mevalonate into P. carinii CoQ was not enhanced by treating cells with lovastatin, suggesting that the cells did not transport the drug, or that a lovastatin-insensitive pathway for de novo synthesis of isoprenoids may also function in this organism. Radiolabeled precursors of the ring moiety, including shikimic acid, p-hydroxybenzoic acid, and tyrosine were also incorporated into P. carinii CoQ. Unexpectedly, it was found that not only CoQ9 and CoQ10, but also CoQ7, and CoQ8, were metabolically radiolabeled by all the precursors tested, indicating that the organism synthesizes CoQ7, CoQ8, CoQ9, and CoQ10. Metabolic radiolabeling of ubiquinones in rat lung controls was not detected in experiments using either radioactive mevalonate or p-hydroxybenzoate. Thus the incorporations measured using purified P. carinii preparations were due to the enzymes of the organism.
KW - AIDS
KW - High performance liquid chromatography
KW - Lovastatin
KW - Mevalonic acid
KW - P-hydroxybenzoic acid
KW - Phosphoenolpyruvate
KW - Shikimic acid
KW - Tyrosine
UR - http://www.scopus.com/inward/record.url?scp=0034925981&partnerID=8YFLogxK
UR - http://www.scopus.com/inward/citedby.url?scp=0034925981&partnerID=8YFLogxK
M3 - Article
VL - 48
SP - 182
EP - 187
JO - Journal of Eukaryotic Microbiology
JF - Journal of Eukaryotic Microbiology
SN - 1066-5234
IS - 2
ER -