Ultralight Ultrafast Enzymes

Inorganic materials depleted of heavy stable isotopes are known to deviate strongly in some physicochemical properties from their isotopically natural counterparts. Here we explored for the first time the effect of simultaneous depletion of the heavy carbon, hydrogen, oxygen and nitrogen isotopes on the bacterium E. coli and the enzymes expressed in it. Bacteria showed faster growth, with most proteins exhibiting higher thermal stability, while for recombinant enzymes expressed in depleted media, faster kinetics was discovered. At room temperature, luciferase, thioredoxin and dihydrofolate reductase and Pfu DNA polymerase showed up to a 250 % increase in activity compared to the native counterparts, with an additional similar to 50 % increase at 10 degrees C. Diminished conformational and vibrational entropy is hypothesized to be the cause of the accelerated kinetics. Ultralight enzymes may find an application where extreme reaction rates are required. An M9 minimum media based on 13C-depleted glucose and 15N-depleted salt dissolved in D,18O-depleted water (Depleted media) was formulated. E. coli bacteria grow faster in Depleted media compared with isotopically natural media (Normal media). In addition, four different enzymes recombinantly produced in Depleted media showed faster kinetics compared with the enzymes produced in Normal media.**+image

Automated summary

This study investigated the effects of simultaneous depletion of heavy carbon, hydrogen, oxygen, and nitrogen isotopes on the bacterium E. coli and the enzymes expressed in it. The results showed that bacteria and enzymes grown in depleted media exhibited faster kinetics, possibly due to diminished conformational and vibrational entropy.