The interaction of DNA duplexes containing 2-aminopurine with restriction endonucleases EcoRII and SsoII.
Oligonucleotides containing 2-aminopurine (2-AP) in place of G or A in the recognition site of EcoRII (CCT/AGG) or SsoII (CCNGG) restriction endonucleases have been synthesized in order to investigate the specific interaction of DNA with these enzymes. Physicochemical properties (CD spectra and melting behaviour) have shown that DNA duplexes containing 2-aminopurine exist largely in a stable B-like form. 2-Aminopurine base paired with cytidine, however, essentially influences the helix structure. The presence of a 2-AP-C mismatch strongly reduces the stability of the duplexes in comparison with the natural double strand, indicated by a biphasic melting behaviour. SsoII restriction endonuclease recognizes and cleaves the modified substrate with a 2-AP-T mismatch in the centre of the recognition site, but it does not cleave the duplexes containing 2-aminopurine in place of inner and outer G, or both. EcoRII restriction endonuclease does not cleave duplexes containing 2-aminopurine at all. The two-substrate mechanism of EcoRII-DNA interaction, however, allows hydrolysis of the duplex containing 2-aminopurine in place of adenine in the presence of the canonical substrate.
Petrauskene
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OV
A. N. Belozersky Institute of Physico-Chemical Biology, Moscow State University, Russia.
Schmidt
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S
Karyagina
A S
AS
Nikolskaya
I I
II
Gromova
E S
ES
Cech
D
D
D015075:2-Aminopurine / Q000737:chemistry*; D001482:Base Composition; D001483:Base Sequence; D001665:Binding Sites; D055598:Chemical Phenomena; D002627:Chemistry, Physical; D002942:Circular Dichroism; D004247:DNA / Q000737:chemistry* / Q000378:metabolism*; D015252:Deoxyribonucleases, Type II Site-Specific / Q000378:metabolism*; D006860:Hydrogen Bonding; D008969:Molecular Sequence Data; D009690:Nucleic Acid Conformation; D013329:Structure-Activity Relationship
D015075:2-Aminopurine; D004247:DNA; C045297:CCNGG-specific type II deoxyribonucleases; C046545:CCWGG-specific type II deoxyribonucleases; D015252:Deoxyribonucleases, Type II Site-Specific