Biopolymers and cell. 2001; 17 (5): 388 - 395

The possible molecular mechanisms of untargeted type mutations formation under SOS-replication of two-stranded DNA

O. A. Grebneva, M. O. Ivanov

The possible molecular mechanisms of untargeted type mutations formation analyse under SOS-replication of the two-stranded DNA after UV'-irradiation. It is suggested the SOS-system induction cause weaking of the control of the tautomeric state matrix DNA. It is shown in this case one of the possible untargeted mutations sources is the transition the paired bases in rare tautomeric forms when H'4 and HI in G-C paired bases and H'6 and H3 in A-T paired bases pass to H-bond partners simultaneously. It results A-T-*G-C and G-C^A-T transitions or A-T-*T-A and G-C-»C-G homologous transversions if the bases are in rare tautomeric forms arise under W-irradiating near a photodimer.