title: DNA duplexes containing altered sugar residues as probes of EcoRII and MvaI endonuclease interactions with sugar-phosphate backbone.
abstract: Oligonucleotides containing 1-(beta-D-2'-deoxy-threo-pentofuranosyl)cytosine (dCx) and/or 1-(beta-D-2'-deoxy-threo-pentofuranosyl)thymine (dTx) in place of dC and dT residues in the EcoRII and MvaI recognition site CC(A/T)GG were synthesized in order to investigate specific recognition of the DNA sugar-phosphate backbone by EcoRII and MvaI restriction endonucleases. In 2'-deoxyxylosyl moieties of dCx and dTx, 3'-hydroxyl groups were inverted, which perturbs the related individual phosphates. Introduction of a single 2'-deoxyxylosyl moiety into a dC x dG pair resulted in a minor destabilization of double-stranded DNA structure. In the case of a dA x dT pair the effect of a 2'-deoxyxylose incorporation was much more pronounced. Multiple dCx modifications and their combination with dTx did not enhance the destabilization effect. Hydrolysis of dCx-containing DNA duplexes by EcoRII endonuclease was blocked and binding affinity was strongly depended on the location of an altered sugar. A DNA duplex containing a dTx residue was cleaved by the enzyme, but kcat/K(M) was slightly reduced. In contrast, MvaI endonuclease efficiently cleaved both types of sugar-altered substrate analogs. However it did not cleave conformationally perturbed scissile bonds, when the corresponding unmodified bonds were perfectly hydrolyzed in the same DNA duplexes. Based on these data the possible contributions of individual phosphates in the recognition site to substrate recognition and catalysis by EcoRII were proposed. We observed strikingly non-equivalent inputs for different phosphates with respect to their effect on EcoRII-DNA complex formation.
authors.affiliation: Department of Chemistry and Belozersky Institute of Physico-Chemical Biology, Moscow State University, Russia.
authors.forename: O V
authors.initials: OV
authors.lastname: Petrauskene
authors.forename: J N
authors.initials: JN
authors.lastname: Yakovleva
authors.forename: Y I
authors.initials: YI
authors.lastname: Alekseev
authors.forename: F V
authors.initials: FV
authors.lastname: Subach
authors.forename: O V
authors.initials: OV
authors.lastname: Babkina
authors.forename: E S
authors.initials: ES
authors.lastname: Gromova
mesh_terms: D002241:Carbohydrates / Q000737:chemistry; D002855:Chromatography, Thin Layer; D002942:Circular Dichroism; D004247:DNA / Q000737:chemistry / Q000378:metabolism*; D015342:DNA Probes; D015257:DNA-Cytosine Methylases / Q000737:chemistry / Q000378:metabolism*; D015252:Deoxyribonucleases, Type II Site-Specific / Q000737:chemistry / Q000378:metabolism*; D007700:Kinetics; D008956:Models, Chemical; D009841:Oligonucleotides / Q000737:chemistry / Q000378:metabolism; D010710:Phosphates / Q000737:chemistry; D013696:Temperature
chemical_list: D002241:Carbohydrates; D015342:DNA Probes; D009841:Oligonucleotides; D010710:Phosphates; D004247:DNA; C029528:DNA modification methylase EcoRII; D015257:DNA-Cytosine Methylases; C046545:CCWGG-specific type II deoxyribonucleases; D015252:Deoxyribonucleases, Type II Site-Specific