Pt(1R, 2R-dach)22+與DNA結合之序列偏好

Sequence preferences of Pt(1R, 2R-dach)22+

游岳寧(Yueh-Ning Yu)

指導教授 ： 黃文彰

國立臺灣師範大學/理學院/化學系/碩士(2010年)

摘要

本研究係針對 cis-Pt(NH3)2Cl2 (cisplatin) 的衍生物， Pt(1R, 2R-dach)22+ (dach:diaminocyclohexane) ，探討其與cisplatin 反應途徑之異同，與反應條件及序列之偏好。
經由與cisplatin相同條件實驗結果，顯示 Pt(1R, 2R-dach)22+ 不會如 cisplatin 之反應途徑，與 DNA 產生 cis-GG 的交聯鍵結反應。
根據 UV 及 CD 升溫圖譜研究顯示 Pt(1R, 2R-dach)22+ 可與 AT-rich 之 DNA 序列產生溝槽結合反應。反應條件溫度需 40℃ ，
Pt(1R, 2R-dach)22+:DNA則需在 30:1 以上，為本實驗可產生反應之必要條件。
由本實驗 10 條 DNA 序列之 UV 及 CD 升溫圖譜分析，Pt(1R, 2R-dach)22+ 對含單結合位置的 DNA 序列，其結合強度皆不強，而對含雙結合位置的 DNA 序列則都近乎完全反應，推測d(CXXCGXXG)2 及d(CXXCCGGXXG)2 (X=A或T) 為 Pt(1R, 2R-dach)22+ 偏好之 DNA 序列特徵，為至少 2 組連續 A 或 T 的鹼基對，此協同性結合(cooperative binding) 為正協同作用 (positive cooperativity)。

關鍵字

DNA結合 ； Pt(1R, 2R-dach)22+ ； 順鉑

並列摘要

This investigation was carried out via a cis-Pt(NH3)2Cl2 (cisplatin) derivative, Pt(1R, 2R-dach)22+ (dach:diaminocyclohexane), and focused on the different reaction pathways, reaction conditions and sequence preferences between cisplatin and Pt(1R, 2R-dach)22+.
Under the same experiment conditions as cisplatin, the results suggested Pt(1R, 2R-dach)22+ do not follow the same mechanism as cisplatin, in forming cis-GG crosslink with DNA.
Based on variable temperature UV and CD denaturation analysis, Pt(1R, 2R-dach)22+ can react with AT-rich DNA sequences through groove binding. Based on experiments carried out under various conditions, suggested that reaction temperature about 40℃ and Pt(1R, 2R-dach)22+:DNA over 30:1 were required to promote the reaction.
Refer to UV and CD denaturation experiment of ten DNA samples of variable sequences in this work, Pt(1R, 2R-dach)22+ has only weak binding affinity to single binding site sequences, whereas double binding site sequences react almost completely with Pt(1R, 2R-dach)22+. The variable sequence studies suggested that the consensus sequences of Pt(1R, 2R-dach)22+-DNA sites are d(CXXCGXXG)2 and d(CXXCCGGXXG)2 (X=A or T) with at least 2 base pairs of A or T.

並列關鍵字

DNA binding ； Pt(1R, 2R-dach)22+ ； cisplatin

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