嘌呤核苷 C∵N9糖苷键 H 2 HN H H,N- C-N HC N HOHa H H H OH H OH OH 脱氧鸟嘌呤核苷dGR 腺嘌呤核苷ARC1'-N9糖苷键 9 嘌呤核苷 脱氧鸟嘌呤核苷dGR R