Binding Mode ofmeso-Tetrakis(N-methylpyridinium-4-yl)porphyrin to Poly[d(I−C)2]:  Effect of Amino Group at the Minor Groove of Poly[d(G−C)2] on the Porphyrin−DNA Interaction

2002 ◽  
Vol 106 (43) ◽  
pp. 11351-11355 ◽  
Author(s):  
Young-Ae Lee ◽  
Soomin Lee ◽  
Tae-Sub Cho ◽  
Cheal Kim ◽  
Sung Wook Han ◽  
...  
2008 ◽  
Vol 86 (3) ◽  
pp. 244-250 ◽  
Author(s):  
C.N. N’soukpoé-Kossi ◽  
S. Diamantoglou ◽  
H.A. Tajmir-Riahi

Human DNase I is an endonuclease that catalyzes the hydrolysis of double-stranded DNA predominantly by a single-stranded nicking mechanism under physiological conditions in the presence of divalent Mg and Ca cations. It binds to the minor groove and the backbone phosphate group and has no contact with the major groove of the right-handed DNA duplex. The aim of this study was to examine the effects of DNase I – DNA complexation on DNA and protein conformations.We monitored the interaction of DNA with DNase I under physiological conditions in the absence of Mg2+, with a constant DNA concentration (12.5 mmol/L; phosphate) and various protein concentrations (10–250 µmol/L). We used Fourier transfrom infrared, UV-visible, and circular dichroism spectroscopic methods to determine the protein binding mode, binding constant, and effects of polynucleotide–enzyme interactions on both DNA and protein conformations. Structural analyses showed major DNase–PO2 binding and minor groove interaction, with an overall binding constant, K, of 5.7 × 105 ± 0.78 × 105 (mol/L)–1. We found that the DNase I – DNA interaction altered protein secondary structure, with a major reduction in α helix and an increase in β sheet and random structures, and that a partial B-to-A DNA conformational change occurred. No DNA digestion was observed upon protein–DNA complexation.


Microbiology ◽  
2005 ◽  
Vol 151 (9) ◽  
pp. 2861-2872 ◽  
Author(s):  
Marco Ventura ◽  
John G. Kenny ◽  
Ziding Zhang ◽  
Gerald F. Fitzgerald ◽  
Douwe van Sinderen

The so-called clp genes, which encode components of the Clp proteolytic complex, are widespread among bacteria. The Bifidobacterium breve UCC 2003 genome contains a clpB gene with significant homology to predicted clpB genes from other members of the Actinobacteridae group. The heat- and osmotic-inducibility of the B. breve UCC 2003 clpB homologue was verified by slot-blot analysis, while Northern blot and primer extension analyses showed that the clpB gene is transcribed as a monocistronic unit with a single promoter. The role of a hspR homologue, known to control the regulation of clpB and dnaK gene expression in other high G+C content bacteria was investigated by gel mobility shift assays. Moreover the predicted 3D structure of HspR provides further insight into the binding mode of this protein to the clpB promoter region, and highlights the key amino acid residues believed to be involved in the protein–DNA interaction.


2019 ◽  
Vol 48 (4) ◽  
pp. 2091-2106 ◽  
Author(s):  
Deepak Kumar Yadav ◽  
Dagmar Zigáčková ◽  
Maria Zlobina ◽  
Tomáš Klumpler ◽  
Christelle Beaumont ◽  
...  

Abstract Staufen1 (STAU1) is a dsRNA binding protein mediating mRNA transport and localization, translational control and STAU1-mediated mRNA decay (SMD). The STAU1 binding site (SBS) within human ADP-ribosylation factor1 (ARF1) 3′UTR binds STAU1 and this downregulates ARF1 cytoplasmic mRNA levels by SMD. However, how STAU1 recognizes specific mRNA targets is still under debate. Our structure of the ARF1 SBS–STAU1 complex uncovers target recognition by STAU1. STAU1 dsRNA binding domain (dsRBD) 4 interacts with two pyrimidines and one purine from the minor groove side via helix α1, the β1–β2 loop anchors the dsRBD at the end of the dsRNA and lysines in helix α2 bind to the phosphodiester backbone from the major groove side. STAU1 dsRBD3 displays the same binding mode with specific recognition of one guanine base. Mutants disrupting minor groove recognition of ARF1 SBS affect in vitro binding and reduce SMD in vivo. Our data thus reveal how STAU1 recognizes minor groove features in dsRNA relevant for target selection.


2005 ◽  
Vol 61 (a1) ◽  
pp. c219-c219
Author(s):  
K. Van Hecke ◽  
P. Cam Nam ◽  
M. T. Nguyen ◽  
L. Van Meervelt
Keyword(s):  

2020 ◽  
Vol 25 (3) ◽  
pp. 395-409 ◽  
Author(s):  
Andjela A. Franich ◽  
Marija D. Živković ◽  
Tatjana Ilić-Tomić ◽  
Ivana S. Đorđević ◽  
Jasmina Nikodinović-Runić ◽  
...  

2011 ◽  
Vol 2011 ◽  
pp. 1-8 ◽  
Author(s):  
Nahid Shahabadi ◽  
Somaye Mohammadi ◽  
Robabeh Alizadeh

A new mononuclear Pt(II) complex, [Pt(DMP)(DIP)]Cl2.H2O, in which DMP is 4,4-dimethyl-2,2-bipyridine and DIP is 4,7-diphenyl-1,10-phenantroline, has been synthesized and characterized by physicochemical and spectroscopic methods. The binding interaction of this complex with calf thymus DNA (CT-DNA) was investigated using fluorimetry, spectrophotometry, circular dichroism, viscosimetry and cyclic voltametry (CV). UV-VIS spectrum showed 4 nm bathochromic shift of the absorption band at 280 nm along with significant hypochromicity for the absorption band of the complex. The intrnisic binding constant is more in keeping with intercalators and suggests this binding mode. The viscosity measurements showed that the complex-DNA interaction can be hydrophobic and confirm intercalation. Moreover, the complex induced detectable changes in the CD spectrum of CT-DNA. The fluorescence studies revealed that the probable quenching mechanism of fluorescence of the complex by CT-DNA is static quenching. The thermodynamic parameters ( and ) showed that main interaction with hydrogenic forces occurred that is intercalation mode. Also, CV results confirm this mode because, with increasing the CT-DNA concentration, shift to higher potential was observed.


2012 ◽  
Vol 16 (11) ◽  
pp. 1159-1166 ◽  
Author(s):  
Changyun Lee ◽  
Lindan Gong ◽  
Youngku Shon ◽  
Young Sun Lee ◽  
Suk Joong Lee ◽  
...  

The binding mode of a porphyrin dimer to double stranded native DNA was investigated in this study using normal electric absorption, circular dichroism (CD) and linear dichroism (LD) spectroscopies. At the time of mixing, the spectral properties of the porphyrin dimer upon its association with DNA were characterized by hypochromism and a red shift in the absorption spectrum and by complicated CD and negative LD in the Soret region. As time elapsed, the CD spectrum became a negative single band and the negative LD signal increased. These spectral changes suggested that the majority of both porphyrin moieties of the dimer intercalated between the DNA base-pairs. The changes in the spectral characteristics of the DNA bound porphyrin-dimer were similar when the minor groove of DNA was saturated by 4′,6-diamidino-2-phenylindole (DAPI), which is well-known minor groove binding molecule. The spectral properties of DAPI, which can be summarized by a large positive induced CD in the DAPI absorption region (300~400 nm) and wavelength-independent positive reduced LD, remained intact when the porphyrin dimer was present. These observations indicated that both DAPI and porphyrin bind to DNA simultaneously, and furthermore, the bis-intercalation of the porphyrin dimer occurs in the major groove.


2019 ◽  
Author(s):  
Vasudha Sharma ◽  
Sharmistha MAJUMDAR

Abstract Background: ChIP (Chromatin immunoprecipitation)-exo has emerged as an important and versatile improvement over conventional ChIP-seq as it reduces the level of noise, maps the transcription factor (TF) binding location in a very precise manner, upto single base-pair resolution, and enables binding mode prediction. Availability of numerous peak-callers for analyzing ChIP-exo reads has motivated the need to assess their performance and report which tool executes reasonably well for the task. Results: This study has focussed on comparing peak-callers that report direct binding events with those that report indirect binding events. The effect of strandedness of reads and duplication of data on the performance of peak-callers has been investigated. The number of peaks reported by each peak-caller is compared followed by a comparison of the annotated motifs present in the reported peaks. The significance of peaks is assessed based on the presence of a motif in top peaks. Indirect binding tools have been compared on the basis of their ability to identify annotated motifs and predict mode of protein-DNA interaction. Conclusion: By studying the output of the peak-callers investigated in this study, it is concluded that the tools that use self-learning algorithms, i.e. the tools that estimate all the essential parameters from the aligned reads, perform better than the algorithms which require formation of peak-pairs. The latest tools that account for indirect binding of TFs appear to be an upgrade over the available tools, as they are able to reveal valuable information about the mode of binding in addition to direct binding. Furthermore, the quality of ChIP-exo reads have important consequences on the output of data analysis.


2019 ◽  
Author(s):  
Vasudha Sharma ◽  
Sharmistha Majumdar

AbstractBackgroundChIP (Chromatin immunoprecipitation)-exo has emerged as an important and versatile improvement over conventional ChIP-seq as it reduces the level of noise, maps the transcription factor (TF) binding location in a very precise manner, upto single base-pair resolution, and enables binding mode prediction. Availability of numerous peak-callers for analyzing ChIP-exo reads has motivated the need to assess their performance and report which tool executes reasonably well for the task.ResultsThis study has focussed on comparing peak-callers that report direct binding events with those that report indirect binding events. The effect of strandedness of reads and duplication of data on the performance of peak-callers has been investigated. The number of peaks reported by each peak-caller is compared followed by a comparison of the annotated motifs present in the reported peaks. The significance of peaks is assessed based on the presence of a motif in top peaks. Indirect binding tools have been compared on the basis of their ability to identify annotated motifs and predict mode of protein-DNA interaction.ConclusionBy studying the output of the peak-callers investigated in this study, it is concluded that the tools that use self-learning algorithms, i.e. the tools that estimate all the essential parameters from the aligned reads, perform better than the algorithms which require formation of peak-pairs. The latest tools that account for indirect binding of TFs appear to be an upgrade over the available tools, as they are able to reveal valuable information about the mode of binding in addition to direct binding. Furthermore, the quality of ChIP-exo reads have important consequences on the output of data analysis.


Molecules ◽  
2021 ◽  
Vol 26 (22) ◽  
pp. 7060
Author(s):  
Silvija Maračić ◽  
Petra Grbčić ◽  
Suresh Shammugam ◽  
Marijana Radić Stojković ◽  
Krešimir Pavelić ◽  
...  

The novel 1,2,3-triazolyl-appended N- and O-heterocycles containing amidine 4–11 and amidoxime 12–22 moiety were prepared and evaluated for their antiproliferative activities in vitro. Among the series of amidine-substituted heterocycles, aromatic diamidine 5 and coumarine amidine 11 had the most potent growth-inhibitory effect on cervical carcinoma (HeLa), hepatocellular carcinoma (HepG2) and colorectal adenocarcinoma (SW620), with IC50 values in the nM range. Although compound 5 was toxic to non-tumor HFF cells, compound 11 showed certain selectivity. From the amidoxime series, quinoline amidoximes 18 and 20 showed antiproliferative effects on lung adenocarcinoma (A549), HeLa and SW620 cells emphasizing compound 20 that exhibited no cytostatic effect on normal HFF fibroblasts. Results of CD titrations and thermal melting experiments indicated that compounds 5 and 10 most likely bind inside the minor groove of AT-DNA and intercalate into AU-RNA. Compounds 6, 9 and 11 bind to AT-DNA with mixed binding mode, most probably minor groove binding accompanied with aggregate binding along the DNA backbone.


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