Interaction of cisplatin in activated diaqua-form with His-Met dipeptide is explored using DFT approach with PCM model. First the conformation space of the dipeptide is explored to find the most stable structure (labeled 0683). Several functionals with double-zeta basis set are used for optimization and obtained order of conformers is confirmed by the CCSD(T) single-point calculations. Supermolecular model is used to determine reaction coordinate for the replacement of aqua ligands consequently by N-site of histidine and S-site of methionine and reversely. Despite the monoadduct of Pt-S(Met) is thermodynamically less stable this reaction passes substantially faster (by several orders of magnitude) than coordination of cisplatin to histidine. The consequent chelate formation occurs relatively fast with energy release up to 12 kcal mol-1.

• Klíčová slova
• Anticancer drug, Computational chemistry, Density functional theory, Heavy metal, Thermodynamics,
• MeSH
• antitumorózní látky chemie   MeSH
• chelátory chemie   MeSH
• cisplatina chemie   MeSH
• dipeptidy chemie   MeSH
• histidin chemie   MeSH
• kinetika MeSH
• methionin chemie   MeSH
• teorie funkcionálu hustoty * MeSH
• termodynamika MeSH
• Publikační typ
• časopisecké články MeSH
• práce podpořená grantem MeSH
• Názvy látek
• antitumorózní látky MeSH
• chelátory MeSH
• cisplatina MeSH
• dipeptidy MeSH
• histidin MeSH
• methionin MeSH

Triplex DNA is implicated in a wide range of biological activities, including regulation of gene expression and genomic instability leading to cancer. The tumor suppressor p53 is a central regulator of cell fate in response to different type of insults. Sequence and structure specific modes of DNA recognition are core attributes of the p53 protein. The focus of this work is the structure-specific binding of p53 to DNA containing triplex-forming sequences in vitro and in cells and the effect on p53-driven transcription. This is the first DNA binding study of full-length p53 and its deletion variants to both intermolecular and intramolecular T.A.T triplexes. We demonstrate that the interaction of p53 with intermolecular T.A.T triplex is comparable to the recognition of CTG-hairpin non-B DNA structure. Using deletion mutants we determined the C-terminal DNA binding domain of p53 to be crucial for triplex recognition. Furthermore, strong p53 recognition of intramolecular T.A.T triplexes (H-DNA), stabilized by negative superhelicity in plasmid DNA, was detected by competition and immunoprecipitation experiments, and visualized by AFM. Moreover, chromatin immunoprecipitation revealed p53 binding T.A.T forming sequence in vivo. Enhanced reporter transactivation by p53 on insertion of triplex forming sequence into plasmid with p53 consensus sequence was observed by luciferase reporter assays. In-silico scan of human regulatory regions for the simultaneous presence of both consensus sequence and T.A.T motifs identified a set of candidate p53 target genes and p53-dependent activation of several of them (ABCG5, ENOX1, INSR, MCC, NFAT5) was confirmed by RT-qPCR. Our results show that T.A.T triplex comprises a new class of p53 binding sites targeted by p53 in a DNA structure-dependent mode in vitro and in cells. The contribution of p53 DNA structure-dependent binding to the regulation of transcription is discussed.

• MeSH
• aktivace transkripce genetika   MeSH
• DNA vazebné proteiny chemie   genetika   MeSH
• DNA chemie   genetika   MeSH
• konformace nukleové kyseliny MeSH
• lidé MeSH
• nádorový supresorový protein p53 chemie   genetika   MeSH
• nukleotidové motivy genetika   MeSH
• plazmidy genetika   MeSH
• promotorové oblasti (genetika) MeSH
• regulační oblasti nukleových kyselin genetika   MeSH
• sekvenční delece genetika   MeSH
• vazebná místa MeSH
• Check Tag
• lidé MeSH
• Publikační typ
• časopisecké články MeSH
• Názvy látek
• DNA vazebné proteiny MeSH
• DNA MeSH
• nádorový supresorový protein p53 MeSH
• TP53 protein, human MeSH Prohlížeč
• triplex DNA MeSH Prohlížeč

The trinuclear platinum agent BBR3464, a representative of a new class of anticancer drugs, is more potent than conventional mononuclear cisplatin [cis-diamminedichloroplatinum(II)]. BBR3464 retains significant activity in human tumor cell lines and xenografts that are refractory or poorly responsive to cisplatin, and displays a high activity in human tumor cell lines that are characterized by both wild-type and mutant p53 gene. In contrast, on average, cells with mutant p53 are more resistant to the effect of cisplatin. It has been hypothesized that the sensitivity or resistance of tumor cells to cisplatin might be also associated with cell cycle control and repair processes that involve p53. DNA is a major pharmacological target of platinum compounds and DNA binding activity of the p53 protein is crucial for its tumor suppressor function. This study, using gel-mobility-shift assays, was undertaken to examine the interactions of active and latent p53 protein with DNA fragments and oligodeoxyribonucleotide duplexes modified by BBR3464 in a cell free medium and to compare these results with those describing the interactions of these proteins with DNA modified by cisplatin. The results indicate that structurally different DNA adducts of BBR3464 and cisplatin exhibit a different efficiency to affect the binding affinity of the modified DNA to p53 protein. It has been suggested that different structural perturbations induced in DNA by the adducts of BBR3464 and cisplatin produce a differential response to p53 protein activation and recognition and that a 'molecular approach' to control of downstream effects such as protein recognition and pathways of apoptosis induction may consist in design of structurally unique DNA adducts as cell signals.

• MeSH
• adukty DNA chemie   účinky léků   genetika   metabolismus   MeSH
• antitumorózní látky chemie   farmakologie   MeSH
• cisplatina chemie   farmakologie   MeSH
• konsenzuální sekvence genetika   MeSH
• nádorový supresorový protein p53 genetika   metabolismus   MeSH
• organoplatinové sloučeniny chemie   farmakologie   MeSH
• responzivní elementy genetika   MeSH
• sekvence nukleotidů MeSH
• substrátová specifita MeSH
• vazba proteinů MeSH
• Publikační typ
• časopisecké články MeSH
• práce podpořená grantem MeSH
• Research Support, U.S. Gov't, P.H.S. MeSH
• Názvy látek
• adukty DNA MeSH
• antitumorózní látky MeSH
• BBR 3464 MeSH Prohlížeč
• cisplatina MeSH
• nádorový supresorový protein p53 MeSH
• organoplatinové sloučeniny MeSH