Delivery of respiratory chain enzymes into membrane mimicking systems by charge-mediated fusion

Biner, Olivier Felix; von Ballmoos, Christoph (4 June 2017). Delivery of respiratory chain enzymes into membrane mimicking systems by charge-mediated fusion (Unpublished). In: Gordon research conference - Bioenergetics. Andover, New Hampshire, USA. 04.-09.06.2017.

During oxidative phosphorylation, membrane embedded complexes I to V functionally interact to form ATP from cellular reducing equivalents. Normally, these enzymes are investigated individually and therefore, their functional interplay is not yet understood in detail. To get further insights on interactions of respiratory chain enzymes on a molecular basis such as the formation of supercomplexes, they have to be co-reconstituted into a well-defined membrane mimicking system such as liposomes. Recently, we found that if two liposome populations either containing negatively or positively charged lipids were mixed, the two populations would rapidly and completely undergo one round of fusion and yield a slightly larger liposomes containing both membrane proteins. Using this strategy, it was possible to co-reconstitute different terminal oxidases and the E. coli ATP synthase, imitating the last step of oxidative phosphorylation. In a next step, we then applied this technique to deliver the ATP synthase, a large multi-subunit complex reconstituted into positively charged liposomes, into native inverted membrane vesicles of E. coli (which contains overall a negative charge) that lack this enzyme. Upon fusion, respiratory driven ATP synthesis activity was restored. However, positively-charged lipids are not found in natural membranes and this might influence the activity of membrane proteins. To overcome this obstacle we currently test ionisable lipids, which are only positively charged below a certain pH threshold.

Item Type:

Conference or Workshop Item (Speech)

Division/Institute:

08 Faculty of Science > Departement of Chemistry and Biochemistry

UniBE Contributor:

Biner, Olivier Felix and von Ballmoos, Christoph

Subjects:

500 Science > 570 Life sciences; biology
500 Science > 540 Chemistry

Language:

English

Submitter:

Olivier Felix Biner

Date Deposited:

04 Jul 2017 13:36

Last Modified:

04 Jul 2017 13:36

URI:

https://boris.unibe.ch/id/eprint/101374

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