| Research Abstract |
(1) Establishment of synthetic route of ^<13>C-labeled nucleosides from labeled glucose ; The stable-isotopically labeled uridine and thymidine are synthesized from labeled glucose in good overall yields. In contrast, the overall yields of the chemical syntheses of labeled purine nucleosides are not satisfactory. In order to overcome this drawback, we examined an enzymatic method for synthesizing purine nucleosides from pyrimidine nucleosides (uridine and thymidine) and purine bases (adenine and diaminopurine) by enzymatic trans-glycosylation reactions. Thus, adenosine, guanosine, 2'-deoxyadenosune, 2'-deoxyguanosine were obtained in over 90% yields from uridine and thymidine.
(2) Application of labeled DNA oligomers to the structural analysis of DNA-protein complexes ; One of the goal of this study is the completion of the structural analysis of high-molecular-weight DNA-protein complexes. As molecular weight become higher, NMR signals become more broad and overlapped more severely. The signal overlaps can be reduced by using a set of residue-selectively labeled DNA oligomers, then the structural information obtained from isotopomers are accumulated to get more precise three dimensional structures. In order to estimate value of above methodology, the complex of 13C/15N-labeled 14mer DNA duplex and antennapedia homeodomain was used for NMR studies. One of the results, the sugar-phosphate backbone structure, BI or BII,of the DNA duplex can be assigned.
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