Time-resolved infra-red studies of photo-excited porphyrins in the presence of nucleic acids and in HeLa tumour cells: insights into binding site and electron transfer dynamics.
Time-resolved infra-red studies of photo-excited porphyrins in the presence of nucleic acids and in HeLa tumour cells: insights into binding site and electron transfer dynamics.
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核酸存在下和 HeLa 肿瘤细胞中光激发卟啉的时间分辨红外研究：深入了解结合位点和电子转移动力学。
DOI：
10.1039/d2cp04604k
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发表时间：
2022
期刊：
影响因子：
--
通讯作者：
S. Quinn
中科院分区：
文献类型：
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作者：
Páraic M Keane;Clara Zehe;F. Poynton;S. Bright;Sandra Estayalo;Stephen J. Devereux;P. Donaldson;I. Sazanovich;M. Towrie;S. Botchway;C. Cardin;D. C. Williams;T. Gunnlaugsson;C. Long;J. Kelly;S. Quinn
基于5，10，15，20-中-(四-4-N-甲基吡啶)核(TMPyP4)的阳离子卟啉(TMPyP4)因其与多种核酸结构的强相互作用以及作为光动力治疗剂和端粒酶抑制剂的潜在用途而被广泛研究。本文首次用时间分辨红外光谱(TRIR)研究了无金属TMPyP4和铂(II)TMPyP4与含鸟嘌呤核酸的相互作用。在D2O溶液中(无金属形式以D2TMPyP4形式存在)，两种化合物在其Soret B吸收带经脉冲激光激发后产生相似的TRIR光谱(在1450-1750 cm-1之间)。密度泛函理论计算表明，以甲基吡啶基团为中心的振动是导致约1640厘米-1处的主要特征的原因。在鸟苷5‘-单磷酸(GMP)、双链{d(GC)5}2或{d(CGCAAATTTGCG)}2存在下，D2TMPyP4或PtTMPyP4的TRIR谱含有负向信号“漂白”，表示结合在鸟氨酸附近。与形成四链的cMYC序列{d(TAGGGAGGG)}2T结合的D2TMPyP4或PtTMPyP的TRIR信号表明，结合发生在堆叠的鸟嘌呤上。对于D2TMPyP4与鸟嘌呤结合的体系，1640 cm-1处的TRIR信号在皮秒尺度上衰减，这与电子从鸟嘌呤转移到D2TMPyP4的单重态激发态相一致，尽管没有观察到还原的卟啉/氧化的鸟嘌呤的红外标记带。当PtTMPyP被掺入HeLa肿瘤细胞中时，TRIR研究表明，蛋白质与酰胺吸收的PS/ns随时间发生变化，这表明TRIR不仅可以研究光激活的分子过程，还可以研究生物细胞中的核酸。
Cationic porphyrins based on the 5,10,15,20-meso-(tetrakis-4-N-methylpyridyl) core (TMPyP4) have been studied extensively over many years due to their strong interactions with a variety of nucleic acid structures, and their potential use as photodynamic therapeutic agents and telomerase inhibitors. In this paper, the interactions of metal-free TMPyP4 and Pt(II)TMPyP4 with guanine-containing nucleic acids are studied for the first time using time-resolved infrared spectroscopy (TRIR). In D2O solution (where the metal-free form exists as D2TMPyP4) both compounds yielded similar TRIR spectra (between 1450-1750 cm-1) following pulsed laser excitation in their Soret B-absorption bands. Density functional theory calculations reveal that vibrations centred on the methylpyridinium groups are responsible for the dominant feature at ca. 1640 cm-1. TRIR spectra of D2TMPyP4 or PtTMPyP4 in the presence of guanosine 5'-monophosphate (GMP), double-stranded {d(GC)5}2 or {d(CGCAAATTTGCG)}2 contain negative-going signals, 'bleaches', indicative of binding close to guanine. TRIR signals for D2TMPyP4 or PtTMPyP bound to the quadruplex-forming cMYC sequence {d(TAGGGAGGG)}2T indicate that binding occurs on the stacked guanines. For D2TMPyP4 bound to guanine-containing systems, the TRIR signal at ca. 1640 cm-1 decays on the picosecond timescale, consistent with electron transfer from guanine to the singlet excited state of D2TMPyP4, although IR marker bands for the reduced porphyrin/oxidised guanine were not observed. When PtTMPyP is incorporated into HeLa tumour cells, TRIR studies show protein binding with time-dependent ps/ns changes in the amide absorptions demonstrating TRIR's potential for studying light-activated molecular processes not only with nucleic acids in solution but also in biological cells.