The Hydrolysis of Dihydrouridine and Related Compounds

摘要

Dihydrouridine is absent from the tRNA of almost all hyperthermophiles and most Archaea, but is ubiquitous in the tRNA of Eubacteria and Eukaryotes. In order to investigate whether this could be due to instability, the rate of ring opening of dihydrouridine was measured from 25 C to 120 C at pH values ranging from 6 to 9. The dihydrouridine ring is stable at 25 C, but the half-life at 100 C and pH 7 is 9.1 hours, which is comparable to the doubling time of hyperthermophiles. This suggests an explanation for the absence of dihydrouridine from the tRNA of low hyperthermophiles. The absence of dihydrouridine from low temperature Archaea may be due to their having descended from hyperthermophiles.