| Budget Amount *help |
¥8,700,000 (Direct Cost: ¥8,700,000)
Fiscal Year 2000: ¥4,100,000 (Direct Cost: ¥4,100,000)
Fiscal Year 1999: ¥4,600,000 (Direct Cost: ¥4,600,000)
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| Research Abstract |
In living organisms, genetic recombination is related to the DNA damage. DNA damage often arises as a result of genetic recombination, DNA replication, and other processes. In prokaryotes, about fifty enzymes participate in the DNA repair reactions. From thermophilic bacteria including hyperthermophile, we have cloned the DNA-repair related genes, which include recombinational repair enzymes (RecA, RuvA, RuvB, RuvC, ssb), base excision repair enzymes (MutM, MutY, EndoIII, EndoV), nucleotide excision repair enzymes (UvrA, UvrB, UvrC, UvrD), mismatch repair-enzymes (MutS, MutL), photolyase, and DNA polymerase I and ligase. Most of these DNA repair systems are common to many organisms, including those of Homo sapiens. These thermophilic enzymes, as expected, were stable. It was also found that the domains of the respective proteins can be easily isolated by partial digestion with protease. Some repair enzymes, including MutM, UvrB, and photolyase, have been crystallized and their three-dimensional structures have been determined. These thermophilic enzymes have been adapted to high temperatures. Some hyperthermophilic repair enzymes dramatically changed its conformation and increased the activity above 75℃
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