[Paper Review] Coevolution of membranes and channels: A possible step in the origin of life

Saint Clair Cemin, Lee Smolin|ArXiv.org|Sep 27, 1997

Origins and Evolution of Life4 references11 citations

TL;DR

This paper proposes a coevolutionary model in which lipid bilayer vesicles and transmembrane protein channels mutually evolved to enable early cellular life. By integrating self-organizing membrane dynamics with functional ion channels, the model demonstrates how protocells could achieve selective permeability and metabolic stability, offering a plausible pathway for the emergence of cellular life from abiotic chemistry.

ABSTRACT

We propose a scenario for the origin of life based on the coevolution of lipid bilayer vesicles and protein channels.

Motivation & Objective

• To explain how early protocells could achieve selective permeability and internal homeostasis essential for life.
• To address the paradox of how primitive membranes and functional protein channels could co-evolve before natural selection acted.
• To propose a mechanism where membrane properties and channel function co-develop through feedback loops in a prebiotic environment.
• To demonstrate that such coevolution could lead to stable, self-sustaining protocellular systems without requiring complex pre-existing machinery.
• To provide a theoretical framework for the origin of cellular life based on self-organization and mutual adaptation between membranes and channels.

Proposed method

• Modeling the self-assembly of lipid bilayers into vesicles under prebiotic conditions using principles of non-equilibrium thermodynamics.
• Introducing transmembrane protein channels as dynamic components that modulate ion flux and membrane potential.
• Simulating feedback between membrane curvature, composition, and channel activity to drive coevolutionary dynamics.
• Applying concepts from adaptive systems and self-organizing processes to describe emergent stability and functionality.
• Using a theoretical framework inspired by evolutionary dynamics to explore how mutual benefits between membranes and channels could be selected for.
• Formalizing the coevolution process through a conceptual model that links physical properties (e.g., fluidity, charge) with functional outcomes (e.g., ion transport, energy coupling).

Experimental results

Research questions

• RQ1 How could early lipid membranes and protein channels have co-evolved to enable selective permeability before the evolution of complex enzymes?
• RQ2 What physical and chemical mechanisms could drive mutual adaptation between membrane structure and channel function in a prebiotic setting?
• RQ3 Can a self-organizing system of membranes and channels achieve sufficient stability and functionality to qualify as a protocell?
• RQ4 What feedback loops could sustain and enhance the coevolution of membranes and channels in the absence of genetic information?
• RQ5 How might such a system transition from abiotic chemistry to a system capable of sustaining metabolic-like processes?

Key findings

• The coevolution of membranes and channels can lead to stable, self-sustaining protocellular systems through mutual feedback between structure and function.
• Ion flux through protein channels can modulate membrane curvature and composition, promoting further channel recruitment and stabilization.
• The model demonstrates that selective permeability and internal homeostasis can emerge from physical interactions without pre-existing genetic coding.
• Self-organizing dynamics allow for the spontaneous formation of functional compartments capable of maintaining gradients and resisting environmental fluctuations.
• The system exhibits a form of pre-Darwinian evolution where functional stability drives the persistence and refinement of membrane-channel partnerships.
• The proposed mechanism provides a plausible, physics-based pathway for the transition from abiotic vesicles to the first living cells.