Skip to Main content Skip to Navigation
Journal articles

Insertion and self-diffusion of a monotopic protein, the Aquifex aeolicus sulfide quinone reductase, in supported lipid bilayers

Abstract : Monotopic proteins constitute a class of membrane proteins that bind tightly to cell membranes, but do not span them. We present a FRAPP (Fluorescence Recovery After Patterned Photobleaching) study of the dynamics of a bacterial monotopic protein, SQR (sulfide quinone oxidoreductase) from the thermophilic bacteria Aquifex aeolicus, inserted into two different types of lipid bilayers (EggPC: L-α-phosphatidylcholine (Egg, Chicken) and DMPC: 1,2-dimyristoyl-sn-glycero-3-phosphocholine) supported on two different types of support (mica or glass). It sheds light on the behavior of a monotopic protein inside the bilayer. The insertion of SQR is more efficient when the bilayer is in the fluid phase than in the gel phase. We observed diffusion of the protein, with no immobile fraction, and deduced from the diffusion coefficient measurements that the resulting inserted object is the same whatever the incubation conditions, i.e. homogeneous in terms of oligomerization state. As expected, the diffusion coefficient of the SQR is smaller in the gel phase than in the fluid phase. In the supported lipid bilayer, the diffusion coefficient of the SQR is smaller than the diffusion coefficient of phospholipids in both gel and fluid phase. SQR shows a diffusion behavior different from the transmembrane protein α-hemolysin, and consistent with its monotopic character. Preliminary experiments in the presence of the substrate of SQR, DecylUbiquinone, an analogue of quinone, component of transmembrane electrons transport systems of eukaryotic and prokaryotic organisms, have been carried out. Finally, we studied the behavior of SQR, in terms of insertion and diffusion, in bilayers formed with lipids from Aquifex aeolicus. All the conclusions that we have found in the biomimetic systems applied to the biological system
Document type :
Journal articles
Complete list of metadatas

https://hal-amu.archives-ouvertes.fr/hal-01435350
Contributor : Laure Azzopardi <>
Submitted on : Friday, January 13, 2017 - 6:31:11 PM
Last modification on : Thursday, July 2, 2020 - 5:17:36 PM

Identifiers

Collections

Citation

Frédéric Harb, Laurence Prunetti, Marie-Thérèse Giudici-Orticoni, Marianne Guiral, Bernard Tinland. Insertion and self-diffusion of a monotopic protein, the Aquifex aeolicus sulfide quinone reductase, in supported lipid bilayers. European Physical Journal E: Soft matter and biological physics, EDP Sciences: EPJ, 2015, 38 (10), pp.110. ⟨10.1140/epje/i2015-15110-8⟩. ⟨hal-01435350⟩

Share

Metrics

Record views

147