本論文利用螢光光譜的分析分法，研究直鏈胜?、環狀胜?與DNA的相互作用，探討是否具有序列選擇性結合(sequence - selective binding)以及胜?與DNA的交互作用是否具有合作作用(cooperativity)。透過胜?與DNA混合溶液的螢光光譜，以Scatchard plot及Hill plot方法計算出胜?與DNA之間相互結合的結合常數與合作係數，進一步證實本小組所合成之胜?與DNA之間存在者相互作用，並藉由實驗的結果分析比較胜?與各式核醣核酸作用的方式之異同。由Scatchard分析結果得知胜?WR-12對序列中含連續A或者T之寡核?酸具有較高的選擇性。胜?YR-12對d(CTTAGACGTC)-d(GACGTCTAAG)之結合能力相較於其他5個寡核?酸，具有較高結合能力。推測YR-12較喜歡與序列分佈C/G與A/T的特殊序列DNA結合。另一方面，分析環狀胜?與三股螺旋DNA相互作用。結果得知環狀胜?除了能與雙股螺旋DNA結合之外，對三股螺旋DNA也具有結合能力。 This thesis reports the studies of sequence-selective binding of linear and cyclic peptides on oligonucleotide duplexes by spectrofluorimetry. Scatchard plots and Hill plots are employed to compute various binding parameters and to determine the cooperativity of the mode of binding. Equilibrium Scatchard analyses indicated that the binding of linear peptide WR-12 to six decanucleotide duplexes may be more selective for oligomers containing runs of consecutive purines or pyrimidines. On the other hand, YR-12 binds better to d(CTTAGACGTC)-d(GACGTCTAAG) than to the other ligomer duplexes, denoting selectivity for evenly distributed C/G and A/T sequences. DNA binding selectivity are also observed for several cyclic peptides containing the XPRK motif and these cyclic peptides also possess some binding affinities on a paper-clip like DNA triple helix.
