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Comparative analysis of UV-induced mutability of ten different codon units in position 211 of the Escherichia coli trpA gene

✍ Scribed by Langhammer, Renate ;Piechocki, Reinhard


Publisher
Springer
Year
1984
Tongue
English
Weight
309 KB
Volume
196
Category
Article
ISSN
0026-8925

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✦ Synopsis


To study the influence of the local base composition upon UV-induced mutability the reversion frequencies of ten trpA mutants with known codon sequences at position 211 were compared. Comparison of mutant strains reverting by the same base substitution type but with different dipyrimidinic sequences reveals the mutagenic character of the pyrimidine-pyrimidine (6-4) photoproduct. The codons GAC and GAT, both reverting by AT-GC transitions and AT-CG transversions in the middle position and harboring the dipyrimidinic sequence CT in the opposite strand, differ in their reversion frequencies sixfold. This difference can only be due to the influence of the different bases in the third codon position upon the mutability of adjacent second bases.