October 2018
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22 Reads
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Publications (5)
![Fluorescence titration of a 3 μM (9 μM monomer) solution of [(βAlaBpy)2-T4Ff]3 with increasing concentrations of Fe(II). Inset shows emission at 420 nm upon excitation at 305 nm with increasing concentrations of Fe(II), and the best fit to a 1:2 binding mode (Hellman and Fried, 2007; Peberdy et al., 2007). Experiments were made in triplicate. Right. Circular Dichroism of a 6 μM solution (18 μM monomer) of [(βAlaBpy)2-T4Ff]3 (dashed line) and in the presence of 90 μM Fe(II) (solid line). All experiments were made in 1 mM phosphate buffer, pH 6.5, 10 mM NaCl at 20°C.](https://www.researchgate.net/publication/328607832/figure/fig2/AS:11431281243019758@1715642443847/Fluorescence-titration-of-a-3-mM-9-mM-monomer-solution-of-bAlaBpy2-T4Ff3-with_Q320.jpg)
![First cluster representative frame of the MD trajectory for the ΛΛ-[(βAlaBpy)2-T4Ff]3Fe2+4 system showing the stable structure of the T4Ff domain. Note the flexible hinge region between the rigid helicate and the T4Ff domain.](https://www.researchgate.net/publication/328607832/figure/fig3/AS:11431281243019759@1715642444073/First-cluster-representative-frame-of-the-MD-trajectory-for-the_Q320.jpg)
![(Left) Anisotropy titration of [(βAlaBpy)2-T4Ff]3Fe2 in 1 mM phosphate buffer, 10 mM NaCl with increasing concentrations of tw-DNA. The best fit to a 1:1 binding mode is shown (curve fitting was performed using DynaFit).(Kuzmic, 1996, 2009) tw-DNA sequences: 5′–CAC CGC TCT GGT CCT C−3′; 5′–CAG GCT GTG AGC GGT G−3′; 5′–GAG GAC CAA CAG CCT G−3′. Right: Model of the interaction between the [(βAlaBpy)2-T4Ff]3Fe2 and the three-way junction, based on the reported pdb structures of an helicate bound to a three-way junction (pdb code 4NCU), and the structure of the fibritin foldon (pdb code 2ET0; Oleksy et al., 2006).](https://www.researchgate.net/publication/328607832/figure/fig4/AS:11431281243103218@1715642444265/Left-Anisotropy-titration-of-bAlaBpy2-T4Ff3Fe2-in-1-mM-phosphate-buffer-10-mM-NaCl_Q320.jpg)
![EMSA DNA binding studies results for [(βAlaBpy)2-T4Ff]3Fe2 helicate. Lanes 1–6, 200 nM tw-Rho-DNA with 0, 150, 250, 500, 1,000, and 2,000 nM of [(βAlaBpy)2-T4Ff]3 and 14 eq. of (NH4)2Fe(SO4)2 ∙ 6 H2O in each lane; lanes 7–10, 200 nM dsDNA with 0, 500, 1,000, and 2,000 nM of [(βAlaBpy)2-T4Ff]3 and 14 eq. of (NH4)2Fe(SO4)2 ∙ 6 H2O in each lane. Samples were resolved on a 10% nondenaturing polyacrylamide gel and 1 × TBE buffer over 35 min at 25°C, and stained with SyBrGold (5 μL in 50 mL of 0.5 × TBE) for 10 min, followed by fluorescence visualization. Oligonucleotide sequences: tw-DNA, 5′–CAC CGC TCT GGT CCT C−3′; 5′–CAG GCT GTG AGC GGT G−3′; 5′–GAG GAC CAA CAG CCT G−3′; dsDNA (only one strand shown) 5′–AAC ACA TGC AGG ACG GCG CTT−3′.](https://www.researchgate.net/publication/328607832/figure/fig5/AS:11431281243019760@1715642444483/EMSA-DNA-binding-studies-results-for-bAlaBpy2-T4Ff3Fe2-helicate-Lanes-1-6-200-nM_Q320.jpg)
October 2018
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154 Reads
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15 Citations
We propose that peptides are highly versatile platforms for the precise design of supramolecular metal architectures, and particularly, for the controlled assembly of helicates. In this context, we show that the bacteriophage T4 Fibritin foldon (T4Ff) can been engineered on its N-terminus with metal-chelating 2,2′-bipyridine units that stereoselectively assemble in the presence of Fe(II) into parallel, three-stranded peptide helicates with preferred helical orientation. Modeling studies support the proposed self-assembly and the stability of the final helicate. Furthermore, we show that these designed mini-metalloproteins selectively recognize three-way DNA junctions over double-stranded DNA.
October 2018
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48 Reads
Journal of Biophotonics
The use of light‐activated triphenylphosphonium‐based antimicrobials to tackle the emerging problem of antimicrobial resistance has been proposed in this study. Chemical modification of phenalenone and perylene with triphenylphosphonium cations enhances their photoantimicrobial activity up to 10⁷ times. Selective targeting of Gram‐positive bacteria is demonstrated. Further details can be found in the article by Roger Bresolí‐Obach, Ignacio Gispert and Diego García Peña et al. (e201800054). Cover art by M. Eugenio Vázquez, @ChemBioUSC
June 2018
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78 Reads
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27 Citations
Journal of Biophotonics
Light‐mediated killing of pathogens by cationic photosensitisers is a promising antimicrobial approach that avoids the development of resistance inherent to the use of antimicrobials. In this study, we demonstrate that modification of different photosensitisers with the triphenylphosphonium cation yields derivatives with excellent photoantimicrobial activity against Gram‐positive bacteria (i.e., S. aureus and E. faecalis). Thus, the triphenylphosphonium functional group should be considered for the development of photoantimicrobials for the selective killing of Gram‐positive bacteria in the presence of Gram‐negative species. This article is protected by copyright. All rights reserved.
November 2017
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91 Reads
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37 Citations
Inspired by natural transcription factors (TFs), researchers have explored the potential of artificial peptides for the recognition of specific DNA sequences, developing increasingly sophisticated systems that not only display excellent DNA binding properties, but also are endowed with new properties not found in their natural counterparts. Here we review some of the developments in the field of artificial peptide-based DNA binders, focusing on the supramolecular and molecular design aspects of such systems.
Citations (3)
... Others explored the potential of the linker to influence the overall structure. For example, Vázquez et al. designed peptide-linked Fe(II) and Co(III) [M 2 L 3 ] x+ complexes [35,40,41], and Sun et al. made use of a homochiral BINOL-containing (BINOL = 1,1'-bi-2-naphthol) scaffold in tandem with chiral amines to obtain enantiopure fac- (ΔΔ) and fac-(ΛΛ) helical species [42,43]. Formation of helical complexes over the related mesocate structures is often a factor of the ligand, for example, Lisboa et al. synthesised a series of [Fe 2 L 3 ] 4+ metallocylindrical arrays and found that while shorter linkers such as 1,3-substituted benzenes or pyridines between the 2,2'-bipyridine-coordinating motif favoured formation of helical structures, a longer 4,4'-diphenylmethylene linker gave a mixture of structurally related helicates and mesocates [8]. ...
- Citing Article
- Full-text available
October 2018
... One hypothesized mode of action is that cationic photosensitizers will more likely interact with the membrane and thus, enable its lethal disruption by light irradiation. As consequence of this accepted principle, most of the new photosensitizers against gram-negative bacteria are characterized by at least one positive charge (Maisch et al., 2014;Wainwright et al., 2015;Bresolí-Obach et al., 2018). ...
- Citing Article
June 2018
Journal of Biophotonics
... Moreover, it was demonstrated that the photoisomerization of azobenzenes can effectively be used to control peptide-DNA binding. [21][22][23] In these examples, only the Z-isomers of azobenzene-peptide conjugates offer the prerequisites for the peptides to bind to DNA allowing for a photocontrol of DNA-binding properties even in living cells. [22,23] Furthermore, additional photolabile groups were introduced that turn a non-binding peptide into a DNA-binding one upon the photoinduced release of an oligodeoxynucleotide (ODN) that initially blocked the DNAbinding sequence of the peptide. ...
- Citing Article
November 2017