Hydrolysis by restriction endonucleases at their DNA recognition sequences substituted with mismatched base pairs.

AUTOR(ES)

Shenoy, S

RESUMO

Restriction endonucleases were tested for their ability to catalyze the cleavage of mismatch-containing recognition sites in DNA. These mismatched base pairs were T.G, U.G, or A.C in covalently closed, circular heteroduplexes prepared by in vitro extension of chemically synthesized oligonucleotide primers annealed to a bacteriophage M13-derived viral DNA. None of the restriction enzymes was able to completely cleave the mismatch-containing recognition sites under standard conditions. However, three of them, SmaI, SalI, and SstI, catalyzed partial digestion leading to an accumulation of DNA singly nicked at the mismatched recognition site. The ability of SmaI and SstI to partially cleave at a mismatch was shown to depend on the nature and position of the mismatch within the corresponding recognition site. In contrast, little or no digestion was obtained with AccI, HincII, HindIII, and KpnI at mismatch-containing sites. Therefore, in some cases a transition-type substitution in only one strand of a recognition site inhibits restriction endonuclease-catalyzed digestion at that site although in others partial digestion occurs.

Documentos Relacionados

• Restriction endonucleases HindII and TaqI cleave DNA with mismatched nucleotides within their recognition sequences.
• Escherichia coli mutS-encoded protein binds to mismatched DNA base pairs.
• Imidazole-imidazole pair as a minor groove recognition motif for T:G mismatched base pairs.
• Dissociation kinetics of 19 base paired oligonucleotide-DNA duplexes containing different single mismatched base pairs.
• Refined crystal structure of an octanucleotide duplex with I.T. mismatched base pairs.