Study findings  Not simply DNA, proteins, and lipids guide evolution.

Lipids in Cells

• Lipids make up to 30% of the dry weight of living cells.

• They are fat in cells and carry out various functions such as receptors, channels, and catalysts.

• Scientists often view lipids as a homogenous layer of round heads and long, flowy tails, ready for proteins to be dropped on.

Role of Respiratory Complex 1 (RC1)

• RC1 is the largest of these respiratory complexes and is essential for cells to produce energy when the body breathes oxygen.

• RC1 is divided into three parts: one that catalyses energy production reactions during respiration, one that moves through the lipid-rich mitochondrial inner membrane, and one that extends into the space between the inner and outer mitochondrial membranes.

Mutations in RC1

• Mutations in RC1 are expected to cause diseases.

• Half of the mutations were in regions that interact with lipids in the mitochondrial membranes.

• Plant lipids have a kinkier structure than their animal counterparts due to their rich in polyunsaturated fatty acids.

Potential of Lipid-Protein Co-Evolution

• The kinkier tails of plant lipids offer greater structural flexibility in the membranes.

• This could have been due to plant-like organisms having faced variegated environmental stresses through history, benefiting from having structurally flexible lipids.

Need for New Tools

• The new study may be the first to support the idea of lipid-protein co-evolution in mitochondrial membranes.

• This opens up the possibility of understanding human health better.

• Existing tools to study lipids are more complex than proteins, and their composition is partly controlled by an individual’s genes; the rest is influenced by diet and other environmental factors.