Die Basenspezifität bei der Induktion von Mutationen durdh salpetrige Säure im Phagen T2

Abstract

In phage T2 treated with nitrous acid (HNO₂) the deamination rates of the amino-bases G, A and HMC can be shifted relative to each other by altering the pH of treatment. Under various pH conditions the variation of the rates of HNO₂-induced r^- mutation and inactivation have been measured and compared to the corresponding alteration of the deamination rates. In this way it was shown, that the deamination of the bases A and HMC can lead to mutagenic changes, whereas the deamination of G can only act lethally. Furthermore it was estimated, that the deamination of any one of 370 base pairs of the rII-region give rise to a mutation. Deamination of ∼1/4 of the bases within the total T2-DNA lead to inactivation.