Structure of 4'-thioDNA which exhibits endonuclease resistance.
4'-thio DNA consisting of 2'-deoxy-4'-thionucleosides exhibits resistance to both endonuclease and 3'-exonuclease cleavages. Interestingly, we found that 4'-thioDNA duplex behaved like RNA molecules in hybridization properties and structural aspects. Here, we have determined the structure of 4'-thioDNA duplex in solution by NMR. Most residues take on C3'-endosugar puckering, which is characteristic to A-form. The major groove of 4'-thioDNA duplex is narrow and deep, while the minor groove is wide and shallow. These features are also characteristic to A-form. Thus, although DNA duplex usually takes on B-form in solution, 4'-thioDNA takes on A-form, like RNA molecules. A-form-like groove features of 4'-thioDNA can account for the fact that 4'-thioDNA duplex interacts with an RNA major groove binder, but not with DNA groove binder. Interaction of 4'-thioDNA with RNase V1 and resistance to endonuclease may also be accounted for in the same context.
Matsugami
Akimasa
A
Suplamolecular Biology, Intrenational Graduate Schools of Arts and Sciences, Yokohama City Univ., 1-7-29 Suehiro-cho, Tsurumi-ku, Yokohama 230-0045, Japan.
Ohyama
Takako
T
Inada
Masashi
M
Inoue
Naonori
N
Minakawa
Noriaki
N
Matsuda
Akira
A
Katahira
Masato
M
D004247:DNA / Q000737:chemistry* / Q000378:metabolism; D004720:Endonucleases / Q000378:metabolism; D008958:Models, Molecular; D019906:Nuclear Magnetic Resonance, Biomolecular; D013872:Thionucleosides / Q000737:chemistry* / Q000378:metabolism
D013872:Thionucleosides; D004247:DNA; D004720:Endonucleases