Protein - the missing link?

Protein molecules can be made to display life-like properties and could be the link between inanimate matter and living things, scientists said yesterday. A team of chemists has succeeded in building protein "ecosystems" that can replicate and form complex interactions that are signatures of living systems.

A team led by Reza Ghadiri, from the Scripps Research Institute, California, constructed a protein that could act as a blueprint for its own replication, providing a scaffold on which molecular building blocks fused to produce new proteins which then replicated again. They found that the system was self-correcting - putting right errors in the building block sequence - and that it displayed elements of competition.

Replicators built from two pieces could fight over potential fusion partners. Two slightly different sequences, A and B, could, for example, compete for the same piece, C. The full-length replicator AC or BC that "won" would then promote its own formation.

Each replicator was found to start a "selfish" cycle of reproducing itself, but could also accelerate the formation of its competitor. In other words, AC could help BC form and vice-versa.