Generating a Primordial Catalytic Fold
Astrobiologists supported in part by the NAI have uncovered a possible scenario of how primordial proteins could evolve as their structure and functions change. The team’s findings also demonstrate that a protein with a surprisingly simple structure compared to today’s proteins can readily support enzymatic function.
Naturally occurring proteins are formed from chains of amino acids that twist and turn into a 3D shape. This intricate ‘folding’ has a profound effect on how the proteins function in a living system as enzymes. A major challenge to understanding enzyme evolution is the exploration of potential origins of the first primitive proteins with enzymatic functions.
The current study, published online in the Dec 9 edition of the journal Nature Chemical Biology, provides new information about a key step in the origins and early evolution of functional proteins. The team of researchers recently created an artificial enzyme from a non-catalytic protein and watched as it evolved in the lab. The protein lost its initial fold, and instead adopted a new structure. In contrast to natural proteins, this structure has not been optimized by extensive evolution and can therefore be regarded a model protoenzyme – an enzyme at a very early stage of evolution.