A novel type of uracil-DNA glycosylase mediating repair of hydrolytic DNA damage in the extremely thermophilic eubacterium Thermus thermophilus.

ABSTRACT: Spontaneous hydrolytic deamination of DNA cytosine and 5-methyl-cytosine residues is an abundant source of C/G (5-meC/G) to T/A transition mutations. As a result of this pressure, at least six different families of enzymes have evolved that initiate repair at U/G (T/G) mispairs, the relevant pre-mutagenic intermediates. The necessarily higher rate of the process at elevated temperatures must pose a correspondingly accentuated problem to contemporary thermophilic organisms and may have been a serious bottleneck in early evolution when life passed through a phase of very high ambient temperatures. Here we show that Thermus thermophilus, an aerobic, Gram-negative eubacterium thriving at up to 85 degrees C, harbors two uracil-DNA glycosylases (UDGs), termed TTUDGA and TTUDGB. According to both

SUBMITTER: Starkuviene V 

PROVIDER: S-EPMC115290 | biostudies-literature | 2002 May

REPOSITORIES: biostudies-literature