The study results showed that the three oldest thioredoxin enzymes -- those thought to have inhabited Earth 4.2 to 3.5 billion years ago -- were able to operate in lower pH environments than the modern thioredoxin enzymes.
"Our analysis indicates that ancient thioredoxin enzymes were well adapted to function under acidic conditions and that they maintained their high level of activity as they evolved in more alkaline environments," said Fernndez.
To measure the temperature range in which the enzymes operated, professor Jose Sanchez-Ruiz and graduate student Alvaro Ingls-Prieto from the Departamento de Qumica-Fsica at the Universidad de Granada in Spain used a technique called differential scanning calorimetry. This method measures the stability of enzymes by heating the enzymes at a constant rate and measuring the heat change associated with their unfolding.
The researchers found that the ancient proteins were stable at temperatures up to 32 degrees Celsius higher than the modern thioredoxins. The experiments showed that the enzymes exhibited higher temperature stability the older they were. The results provide evidence that ancestral thioredoxins adapted to the cooling trend of ancient oceans, as inferred from geological records.
"Our results confirm that life has the remarkable ability to adapt to a wide range of historical environmental conditions; and by extension, life will undoubtedly adapt to future environmental changes, albeit at some cost to many species," said Gaucher.
This study also showed that the experimental resurrection of ancient proteins together with the sensitivity of single-molecule techniques can be a powerful tool for understanding the origin and evolu
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Georgia Institute of Technology Research News