HEИндивидуална стипендия2023–2025

ChemiLUCA · Modelling the chemiosmotic mode of ATP synthesis in protocells

„Хоризонт Европа“ — Действия „Мария Склодовска-Кюри“

Период: 2023-06-01 → 2025-05-31
Финансиране от ЕС: 187 624 €
Участници: 1
Схема: HORIZON-TMA-MSCA-PF-EF

Линиите свързват координатора с партньорите.

Накратко на български

Механизмите за производство на енергия (ATP) в най-ранните предци на живота се изследват чрез тестове с мембрани от мастни киселини и протеини. Това помага да се разбере как първите клетки са поддържали жизнени процеси преди появата на съвременните биологични мембрани.

Този кратък обзор е генериран от изкуствен интелект

Кратко обяснение, генерирано от езиков модел по текста на CORDIS. Оригиналът е по-долу.

Резултати накратко

Modelling the chemiosmotic mode of ATP synthesis in protocells

The goal of the project was to obtain experimental evidence for the hypothesis that chemiosmotic coupling with sodium (or other larger molecules) rather than proton gradients would be advantageous for LUCA, the Last Common Universial Ancestor. LUCA did not have phospholipids typical of biological membranes but its membrane was most likely composed of simple amphiphiles such as fatty acids. Furthermore, could hydrophobic proteins and peptides function in such membranes. The permeability of membranes for ions and solutes was determined using a previously developed method [1]. Fatty acid membranes and hybrid membranes composed of lipids and varying amounts of fatty acids were prepared and tested. In all cases, fatty acids increased the permeability and instability of the membranes but solute gradients could be maintained for relevant time periods in hybrid membranes with up to 50% fatty acids. Remarkably, membrane proteins such as the mitochondrial ATP/ADP carrier and the Na+/H+ antiporter MjNhaA1 could be functionally reconstituted in hybrid membranes, using Perceval HR as fluorescent reporter of the ATP/ADP ratio and pyranine as probe for pH inside the vesicles. Gradients could be generated in hybrid membranes but not in vesicles solely composed of fatty acids, and, as anticipated, the membrane proteins were not functional in fatty acid membranes. Due to health problems, the project could not be completed and was terminated on 30 April 2024. Sadly, Sagar Raturi had to stop his scientific career. 1. Frallicciardi J, Gabba M & Poolman B (2021) Measuring small molecule permeation through biological membranes. Nat Protoc 17: 2620-2646. doi: 10.1038/s41596-022-00734-2

Текст от CORDIS, на английски · Данни: CORDIS, © Европейски съюз

Цел на проекта

All modern organisms feature chemiosmosis (ion-motive-force driven processes, including membrane transport and ATP production), and therefore the Last Common Universal Ancestor (LUCA) is believed to be chemiosmotic; although contradictorily. As for chemiosmosis to happen, cells utilise membranes relatively impermeable to the coupling ion (H+ or Na+). It has previously been shown that, theoretically, LUCA could drive chemiosmosis using a geo-chemical H+-gradient but only if it had a leaky membrane. However, a leaky membrane rapidly achieves electrochemical equilibrium offsetting theH+ influx. For the H+ influx, and therefore chemiosmosis, to continue, the membrane needs a system to pump H+.Paradoxically, pumping H+ across a leaky membrane is futile. A potential solution has previously been hypothesised in the form of membranes leaky to H+ that harboured: an ATP-synthase coupled to both H+ and Na+, and an antiporter that pumps out Na+ for incoming H+. Such a Na+/H+ antiporter could convert the geochemical H+ gradient into a Na+-gradient. It would be advantageous to do so as a Na+-gradient could be better sustained by the LUCA membrane and could drive ATP production via the promiscuous ATP-synthase. My project aims at obtaining empiricalmvalidation for this hypothesis. To do so, a promiscuous ATP-synthase will be co-reconstituted, alongside a Na+/H+ antiporter, into fatty-acid-containing hybrid liposomes (made from fatty acids and other amphiphilic (phospho)lipids). Ion-gradients will be imposed on the liposomes by pH-jump ordecarboxylase-catalysed alkalisation methods to test whether the system could: a) convert the H+-gradient into a Na+-gradient via the Na+/H+ antiporter, and b) use the Na+- gradient to drive ATP production via the promiscuous ATP-synthase. This study is critical to understand the evolution of chemiosmotic systems and will have implications in evolutionary and synthetic biology as well as astrobiology.

Оригинален текст от CORDIS (на английски).

Участници

RIJKSUNIVERSITEIT GRONINGEN · GroningenКоординаторНидерландия