Iisc -Team finds old proteins that indicate the leap of life in complexity

One of the greatest mysteries of biology is how simple cells evolved into the complex cells that we see in animals, plants and fungi. Simple cells such as bacteria and archaea usually have fewer parts and easier machines. Eukaryotic cells, on the other hand, have extensive internal structures and complicated systems for sharing and retaining their shape.

To understand how this transition took place, scientists study a special group of Archea called the Asgard Archea. These microbes are considered the nearest living family members of Eukaryotes and their genes give important indications about how complexity arose for the first time.

An important part of this puzzle is the cytoskelet, the network of proteins that gives cells their shape and helps them share. In bacteria, the FTSZ protein is essential for cell division. Eukaryotes rely on related proteins such as tubulin, which perform more advanced functions.

Published in a new study in The EMBO JournalIndian Institute of Science Researchers have reported that OdinarchaetaA member of the Asgard group has two versions of the FTSZ-Gen, together with a tubulin-like gene. This is unusual: most microbes only wear one.

The researchers analyzed the two FTSZ proteins with the help of phylogenetic studies, biochemical tests and cryo-electron microscopy. They investigated how each protein was assembled in the presence of energy -seeing molecules such as GTP and tested whether they could bind to artificial membranes.

The two proteins showed clear behavior. Odinftsz1 formed straight protofilaments comparable to bacterial FTSZ and was able to anchor directly to membranes. Odinfts2 formed unusual spiral -shaped ring -like structures and needed the help of an adapter protein to attach to membranes. When both proteins were tested together, they have had an interaction, which suggests that they can work together in actual cells.

The differences indicate a distribution of labor between the two paralogues. This means that cytoskelete proteins in Archaea can share in specialized roles, a sign of growing cellular complexity. The combination of two FTSZ systems and a tubulin-like protein indicates that Asgard Archea experimented with many structural strategies, making it possible to shake the various cytoskelet machines of eukaryotes.

“These proteins give us a rare snapshot of a turning point in evolution, where life began to build the dynamic skeleton that supports all the higher organisms today,” said Project Saravanan Palani The Hindu. He added that the team will then grow asgard microbes in the lab to “observe these proteins in living cells, making it possible to be a real-time image of one of the greatest jumps in Evolution.”