New Insights into the Interaction of Class II Dihydroorotate Dehydrogenases with Ubiquinone in Lipid Bilayers as a Function of Lipid Composition

International Journal of Molecular Sciences

Wolfgang Knecht¹  Juan Manuel Orozco Rodriguez¹  Hanna P. Wacklin-Knecht²  Anna Leung³  Oliver Bogojevic³  Luke A. Clifton⁴  Giovanna Fragneto⁵ 

[1] Department of Biology & Lund Protein Production Platform, Lund University, Sölvegatan 35, 223 62 Lund, Sweden;Department of Chemistry, Division of Physical Chemistry, Lund University, Naturvetarvägen 26, 222 41 Lund, Sweden;European Spallation Source ERIC, P.O. Box 176, 221 00 Lund, Sweden;ISIS Pulsed Neutron and Muon Source, Rutherford Appleton Laboratory, Didcot OX11 0QX, UK;Institut Laue-Langevin, 71 Avenue des Martyrs, BP 156, 38042 Grenoble, France;

关键词: pyrimidine biosynthesis;    protein–lipid interactions;    membrane proteins;    neutron reflectometry;    ubiquinone;   

DOI  :  10.3390/ijms23052437

来源: DOAJ

【 摘 要 】

The fourth enzymatic reaction in the de novo pyrimidine biosynthesis, the oxidation of dihydroorotate to orotate, is catalyzed by dihydroorotate dehydrogenase (DHODH). Enzymes belonging to the DHODH Class II are membrane-bound proteins that use ubiquinones as their electron acceptors. We have designed this study to understand the interaction of an N-terminally truncated human DHODH (HsΔ29DHODH) and the DHODH from Escherichia coli (EcDHODH) with ubiquinone (Q₁₀) in supported lipid membranes using neutron reflectometry (NR). NR has allowed us to determine in situ, under solution conditions, how the enzymes bind to lipid membranes and to unambiguously resolve the location of Q₁₀. Q₁₀ is exclusively located at the center of all of the lipid bilayers investigated, and upon binding, both of the DHODHs penetrate into the hydrophobic region of the outer lipid leaflet towards the Q₁₀. We therefore show that the interaction between the soluble enzymes and the membrane-embedded Q₁₀ is mediated by enzyme penetration. We can also show that EcDHODH binds more efficiently to the surface of simple bilayers consisting of 1-palmitoyl, 2-oleoyl phosphatidylcholine, and tetraoleoyl cardiolipin than HsΔ29DHODH, but does not penetrate into the lipids to the same degree. Our results also highlight the importance of Q₁₀, as well as lipid composition, on enzyme binding.

【 授权许可】

Unknown