Calcium Binding and Transport by Coenzyme Q

Bogeski, Ivan and Gulaboski, Rubin and Kappl, Reinhard and Mirceski, Valentin and Stefova, Marina and Petreska, Jasmina and Hoth, Markus (2011) Calcium Binding and Transport by Coenzyme Q. Journal of the American Chemical Society, 133 (24). pp. 9293-9303. ISSN 0002-7863

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Coenzyme Q10 (CoQ10) is one of the essential
components of the mitochondrial electron-transport chain
(ETC) with the primary function to transfer electrons along
and protons across the inner mitochondrial membrane (IMM).
The concomitant proton gradient across the IMM is essential
for the process of oxidative phosphorylation and consequently
ATP production. Cytochrome P450 (CYP450) monoxygenase
enzymes are known to induce structural changes in a variety of
compounds and are expressed in the IMM. However, it is
unknown if CYP450 interacts with CoQ10 and how such an
interaction would affect mitochondrial function. Using voltammetry, UV�vis spectrometry, electron paramagnetic resonance
(EPR), nuclear magnetic resonance (NMR), fluorescence microscopy and high performance liquid chromatography�mass
spectrometry (HPLC�MS), we show that both CoQ10 and its analogue CoQ1, when exposed to CYP450 or alkaline media,
undergo structural changes through a complex reaction pathway and form quinone structures with distinct properties. Hereby, one
or both methoxy groups at positions 2 and 3 on the quinone ring are replaced by hydroxyl groups in a time-dependent manner. In
comparison with the native forms, the electrochemically reduced forms of the new hydroxylated CoQs have higher antioxidative
potential and are also now able to bind and transport Ca2þ across artificial biomimetic membranes. Our results open new
perspectives on the physiological importance of CoQ10 and its analogues, not only as electron and proton transporters, but also as
potential regulators of mitochondrial Ca2þ and redox homeostasis.

Item Type: Article
Uncontrolled Keywords: coenzyme Q1, Coenzyme Q10, Calcium binding, ion transfer across mitochondrial membranes, homeostasis, voltammetry, complexation
Subjects: Medical and Health Sciences > Basic medicine
Natural sciences > Chemical sciences
Medical and Health Sciences > Health sciences
Natural sciences > Physical sciences
Divisions: Faculty of Agriculture
Depositing User: Rubin Gulaboski
Date Deposited: 31 Oct 2012 13:13
Last Modified: 31 Oct 2012 13:13

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