(GIST OF SCIENCE REPORTER) OUR UNDERSTANDING OF EVOLUTION

(MAY-2025)

OUR UNDERSTANDING OF EVOLUTION

Context:

Our body is made up of trillions of cells. Inside each cell are many smaller parts including proteins, which are made using instructions from DNA. These proteins perform most of the cell’s jobs — like transporting things, breaking down substances, or acting as messengers.
For decades, scientists have believed that changes (mutations) in DNA drive evolution by making new proteins with new functions.
But this view focuses mainly on proteins and genes. Now, scientists are starting to realize that other molecules like lipids (fats) may also play an important role in how life evolved.

What Are Lipids?

Lipids are fats. Inside cells, lipids make up the membranes, which are like flexible walls that surround and separate different parts of the cell. These membranes are made up of lipid molecules with a water-attracting “head” and two water-repelling “tails.”
Until recently, scientists mostly thought of these lipids as passive packaging — just background material for the proteins that do the “real” work.

The New Study: What Was Discovered?

A research team at CSIR-CCMB Hyderabad wanted to investigate this further. They focused on a very important membrane protein complex called Respiratory Complex 1 (RC1).

What is RC1?

RC1 is a large group of proteins that sits inside mitochondria — the energy-making parts of our cells. It plays a key role in respiration, the process where our cells use oxygen to generate energy. If RC1 doesn’t work properly, it can cause diseases.

RC1 has three parts:

1. One part makes energy inside the mitochondria.

2. One part goes through the membrane and moves hydrogen ions.

3. One part sticks out between membranes, but its full function isn’t clear yet.

Plants vs. Animals

They discovered that lipids are different in plants and animals:

Plant lipids have kinky, flexible tails.
Animal lipids are straighter and more rigid.

These structural differences affect how well proteins fit in the membrane. Using experiments and computer models, they found:

Plant RC1 proteins work best with plant lipids.
Human RC1 proteins work best with human lipids.
If you put a plant RC1 protein into a human cell, it falls apart!

Co-evolution: Proteins and Lipids Evolve Together

This leads to a big idea:

Proteins and lipids in cell membranes have co-evolved — meaning they changed together over time to suit each other.
Especially in mitochondria, where energy generation is critical, this compatibility is key.