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Pilar López-Navajas

Bio: Pilar López-Navajas is an academic researcher from Spanish National Research Council. The author has contributed to research in topics: FtsZ & Medicine. The author has an hindex of 5, co-authored 6 publications receiving 216 citations.

Papers
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Journal ArticleDOI
TL;DR: Gentisic acid was used as a lead to identify additional compounds with better inhibitory characteristics generating a new chemical class of fibroblast growth factor inhibitors that includes the agent responsible for alkaptonuria, and evidence was obtained that this group of inhibitors may be of interest to treat cancer and angiogenesis-dependent diseases.

88 citations

Journal ArticleDOI
TL;DR: This work oriented a soluble form of ZipA (sZipA), with its transmembrane domain substituted by a histidine tag, on supported lipid membranes to study the structure and dynamics of the ZipA-FtsZ bundles formed on a lipid surface.

51 citations

Journal ArticleDOI
TL;DR: The binding of sZipA to GDP-FtsZ is of moderate affinity and does not significantly affect the interactions between FtsZ monomers, and the association model that best describes the CG-SLS data is in qualitative agreement with the sedimentation data.
Abstract: We have characterized the self-association of FtsZ in its GDP-bound state (GDP-FtsZ) and the heteroassociation of FtsZ and a soluble recombinant ZipA (sZipA) lacking the N-terminal transmembrane domain by means of composition gradient-static light scattering (CG-SLS) and by measurement of sedimentation equilibrium. CG-SLS experiments at high ionic strengths and in the presence of 5 mM Mg(2+) show that, while FtsZ self-associates in a noncooperative fashion, sZipA acts as a monomer. CG-SLS data obtained from mixtures of FtsZ (A) and sZipA (B) in the presence of Mg(2+) are quantitatively described by an equilibrium model that takes into account significant scattering contributions from B, A(1), A(2), A(3), A(4), A(5), A(6), A(1)B, A(2)B, A(3)B, and A(4)B. However, in the absence of Mg(2+) (with EDTA), the data are best explained by an equilibrium model in which only B, A(1), A(2), A(3), A(1)B, and A(2)B contribute significantly to scattering. The best-fit molecular weights of monomeric A and B are in good agreement with values calculated from amino acid composition and with values obtained from sedimentation equilibrium. The latter technique also confirmed the interaction between sZipA and GDP-FtsZ. Moreover, the association model that best describes the CG-SLS data is in qualitative agreement with the sedimentation data. From these results, it follows that the binding of sZipA to GDP-FtsZ is of moderate affinity and does not significantly affect the interactions between FtsZ monomers. Under the working conditions used, only one sZipA binds to FtsZ oligomers with a length of six at most. The observed behavior would be compatible with FtsZ fibrils being anchored in vivo to the bacterial inner plasma membrane by substoichiometric binding of membrane-bound ZipA.

41 citations

Journal ArticleDOI
TL;DR: The structural results suggest a functional scenario in which ZipA acts as a flexible tether anchoring bacterial proto‐ring elements to the membrane during the earlier stages of division.
Abstract: The full-length ZipA protein from Escherichia coli, one of the essential elements of the cell division machinery, was studied in a surface model built as adsorbed monolayers. The interplay between lateral packing and molecular conformation was probed using a combined methodology based on the scaling analysis of the surface pressure isotherms and ellipsometry measurements of the monolayer thickness. The observed behavior is compatible with the one expected for an intrinsically disordered and highly flexible protein that is preferentially structured in a random coil conformation. At low grafting densities, ZipA coils organize in a mushroom-like regime, whereas a coil-to-brush transition occurs on increasing lateral packing. The structural results suggest a functional scenario in which ZipA acts as a flexible tether anchoring bacterial proto-ring elements to the membrane during the earlier stages of division.—Lopez-Montero, I., Lopez-Navajas, P., Mingorance, J., Rivas, G., Velez, M., Vicente, M., Monroy, F. ...

25 citations

Posted ContentDOI
09 Aug 2021-bioRxiv
TL;DR: The RBD:ACE2 interaction has higher mechanical stability, larger binding free energy, and a lower dissociation rate in comparison to SARS-CoV-1, which helps to rationalize the different infection patterns of the two viruses.
Abstract: SARS-CoV-2 infections are initiated by attachment of the receptor-binding domain (RBD) on the viral Spike protein to angiotensin-converting enzyme-2 (ACE2) on human host cells. This critical first step occurs in dynamic environments, where external forces act on the binding partners and multivalent interactions play critical roles, creating an urgent need for assays that can quantitate SARS-CoV-2 interactions with ACE2 under mechanical load and in defined geometries. Here, we introduce a tethered ligand assay that comprises the RBD and the ACE2 ectodomain joined by a flexible peptide linker. Using magnetic tweezers and atomic force spectroscopy as highly complementary single-molecule force spectroscopy techniques, we investigate the RBD:ACE2 interaction over the whole physiologically relevant force range. We combine the experimental results with steered molecular dynamics simulations and observe and assign fully consistent unbinding and unfolding events across the three techniques, enabling us to establish ACE2 unfolding as a molecular fingerprint. Measuring at forces of 2-5 pN, we quantify the force dependence and kinetics of the RBD:ACE2 bond in equilibrium. We show that the SARS-CoV-2 RBD:ACE2 interaction has higher mechanical stability, larger binding free energy, and a lower dissociation rate in comparison to SARS-CoV-1, which helps to rationalize the different infection patterns of the two viruses. By studying how free ACE2 outcompetes tethered ACE2, we show that our assay is sensitive to prevention of bond formation by external binders. We expect our results to provide a novel way to investigate the roles of mutations and blocking agents for targeted pharmaceutical intervention.

22 citations


Cited by
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Journal Article
TL;DR: In this paper, the adsorption and subsequent conformational changes of sonicated unilamellar vesicles on silica supports were investigated by quartz crystal microbalance with dissipation monitoring and atomic force microscopy, using mixtures of zwitterionic, negatively charged, and positively charged lipids, both in the presence and in the absence of Ca 2 + ions.
Abstract: Supported lipid bilayers (SLBs) are popular models of cell membranes with potential biotechnological applications, yet the mechanism of SLB formation is only partially understood. In this study, the adsorption and subsequent conformational changes of sonicated unilamellar vesicles on silica supports were investigated by quartz crystal microbalance with dissipation monitoring and atomic force microscopy, using mixtures of zwitterionic, negatively charged, and positively charged lipids, both in the presence and in the absence of Ca 2 + ions. Four different pathways of vesicle deposition could be distinguished. Depending on their charge, vesicles i), did not adsorb; ii), formed a stable vesicular layer; or iii), decomposed into an SLB after adsorption at high critical coverage or iv), at low coverage. Calcium was shown to enhance the tendency of SLB formation for negatively charged and zwitterionic vesicles. The role of vesicle-support, interbilayer, and intrabilayer interactions in the formation of SLBs is discussed.

507 citations

Journal ArticleDOI
TL;DR: This work reconstituted FtsA-dependent recruitment of FtsZ polymers to supported membranes, where both proteins self-organize into complex patterns, such as fast-moving filament bundles and chirally rotating rings, to provide a model for the initial steps of bacterial cell division and illustrate how dynamic polymers can self-Organize into large-scale structures.
Abstract: In bacteria, the tubulin-related GTPase FtsZ and the actin-related protein FtsA cooperate to form the Z-ring required for cytokinesis. Loose and Mitchison now show that FtsZ and FtsA can self-organize into dynamic structures in vitro, providing insights into the potential regulatory interplay of the two proteins.

372 citations

Journal ArticleDOI
TL;DR: Among the wide diversity of naturally occurring phenolic acids, at least 30 hydroxy- and polyhydroxybenzoic acids have been reported in the last 10 years to have biological activities and potential as new leads for the development of pharmaceutical and agricultural products to improve human health and nutrition.
Abstract: Among the wide diversity of naturally occurring phenolic acids, at least 30 hydroxy- and polyhydroxybenzoic acids have been reported in the last 10 years to have biological activities The chemical structures, natural occurrence throughout the plant, algal, bacterial, fungal and animal kingdoms, and recently described bioactivities of these phenolic and polyphenolic acids are reviewed to illustrate their wide distribution, biological and ecological importance, and potential as new leads for the development of pharmaceutical and agricultural products to improve human health and nutrition

298 citations

Journal ArticleDOI
TL;DR: FtsZ, a GTPase distributed in the cytoplasm of most bacteria, is the major component of the machinery responsible for division (the divisome) in Escherichia coli and it interacts with additional proteins that contribute to its function forming a ring at the midcell that is essential to constrict the membrane.
Abstract: FtsZ, a GTPase distributed in the cytoplasm of most bacteria, is the major component of the machinery responsible for division (the divisome) in Escherichia coli. It interacts with additional proteins that contribute to its function forming a ring at the midcell that is essential to constrict the membrane. FtsZ is indirectly anchored to the membrane and it is prevented from polymerizing at locations where septation is undesired. Several properties of FtsZ are mediated by other proteins that function as keepers of the ring. ZipA and FtsA serve to anchor the ring, and together with a set of Zap proteins, they stabilize it. The MinCDE and SlmA proteins prevent the polymerization of FtsZ at sites other than the midcell. Finally, ClpP degrades FtsZ, an action prevented by ZipA. Many of the FtsZ keepers interact with FtsZ through a central hub located at its carboxy terminal end.

123 citations

Journal ArticleDOI
TL;DR: High-resolution imaging of FtsZ in vivo has begun to illuminate the organization of filaments within the Z-ring, and in vivo work has been complemented by reconstitution of Z-rings in vitro to demonstrate the force-generating capacity of FTSZ and explore its mechanism of action.

97 citations