Publications de Giovanni Dietler

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It is shown that temperature-control led ordered layers of dodecylamine,self-assembled on highly oriented pyrolytic graphite (HOPG), are an appropriate substrate for aligning individual DNA molecules. High resolution atomic force microscopy (AFM) permits v ...

We present a theoretical framework for the thermodynamic properties of supercoiling-induced denaturation bubbles in circular double-stranded DNA molecules. We explore how DNA supercoiling, ambient salt concentration, and sequence heterogeneity impact on th ...

Structural differentiation of bacterial chromatin depends on cooperative binding of abundant nucleoid-associated proteins at numerous genomic DNA sites and stabilization of distinct long-range nucleoprotein structures. Histone-like nucleoid-structuring pro ...

Atomic force microscopy (AFM) force-distance curves have become a fundamental tool in several fields of research, such as surface science, materials engineering, biochemistry and biology. Furthermore, they have great importance for the study of surface interactions from a theoretical point of view. Force-distance curves have been employed for the study of numerous materials properties and for the characterization of all the known kinds of surface forces. Since 1989, several techniques of acquisition and ana

Two methods of covalent grafting of a protein onto a calcite surface were developed. Single-molecule force spectroscopy was used to examine the characteristics of individual albumin-albumin polyclonal body complexes. The practical applicability of the prop ...

Interaction of the atomic force microscopy (AFM) tip with the sample can be invasive for soft samples. Frequency Modulation (FM) AFM is gentler because it allows scanning in the non-contact regime where only attractive forces exist between the tip and the ...

Hsp70 is a central molecular chaperone that passively prevents protein aggregation and uses the energy of ATP hydrolysis to solubilize, translocate, and mediate the proper refolding of proteins in the cell. Yet, the molecular mechanism by which the active Hsp70 chaperone functions are achieved remains unclear. Here, we show that the bacterial Hsp70 (DnaK) can actively unfold misfolded structures in aggregated polypeptides, leading to gradual disaggregation. We found that the specific unfolding and disaggreg

The human pathogen Mycobacterium tuberculosis requires the ESX-1 secretion system for full virulence. EspR plays a key role in ESX-1 regulation via direct binding and transcriptional activation of the espACD operon. Here, we describe the crystal structures of EspR, a C-terminally truncated form, EspR Delta 10, as well as an EspR-DNA complex. EspR forms a dimer with each monomer containing an N-terminal helix-turn-helix DNA binding motif and an atypical C-terminal dimerization domain. Structural studies comb

Using numerical simulations, we compare properties of knotted DNA molecules that are either torsionally relaxed or supercoiled. We observe that DNA supercoiling tightens knotted portions of DNA molecules and accentuates the difference in curvature between ...

A wide consensus based on robust experimental evidence indicates pyroglutamylated amyloid-beta isoform (A beta pE3-42) as one of the most neurotoxic peptides involved in the onset of Alzheimer's disease. Furthermore, A beta pE3-42 co-oligomerized with exce ...

The atomic force microscope is a convenient tool to probe living samples at the nanometric scale. Among its numerous capabilities, the instrument can be operated as a namo-indenter to gather information about the mechanical properties of the sample. In thi ...

DNA-protein interactions play an important role in all living organisms on Earth. The advent of atomic force microscopy permitted for the first time to follow and to characterize interaction forces between these two molecular species. After a short descrip ...

All-inorganic perovskite films hold promise for improving the stability of perovskite solar cells (PSCs). However, the 3D alpha phase of narrow-bandgap inorganic perovskites is thermodynamically unstable at room temperature, limiting the development of hig ...

The bacterial gene regulatory regions often demonstrate distinctly organized arrays of RNA polymerase binding sites of illdefined function. Previously we observed a module of closely spaced polymerase binding sites upstream of the canonical promoter of the ...

alpha-Synuclein aggregation and accumulation in Lewy bodies are implicated in progressive loss of dopaminergic neurons in Parkinson disease and related disorders. In neurons, the Hsp70s and their Hsp40-like J-domain co-chaperones are the only known compone ...

The coherent Fluorescence Resonance Energy Transfer (FRET) combined with Scanning Near-Field Optical Microscopy (SNOM) are proposed for the creation of complex and nonlocal entangled states involving hundreds of atoms. Micro- and milli-second decoherence times of the electron excitation occur for rare-earth dopant ions in crystals at low temps., and the characteristic coherent FRET distances for such systems are of the order of 20 nm. Thus, both position and time precision necessary for the quantum manipula

Crystals of hexamethylenetetramine (HMT) with aliphatic dicarboxylic acids in 1:1 molar ratio exhibit different behaviour depending on the number n of carbons in the aliphatic chain. For n=8 and 10, incommensurate phases have been observed, while for n=9, a commensurate disordered phase is found. The structure consists of alternating layers of roughly spherical HMT and acid chains. Atomic force microscope (AFM) has been used in order to characterise these layers in several different crystals. Images have be

A scanning near-field optical microscope (SNOM)-based modification of the method to study the dynamics of single molecule receptor?ligand interactions exploiting the fluorescence imaging by total internal reflection fluorescence microscopy is introduced. T ...

The formation of amyloid fibrils is a characterizing feature of a range of protein misfolding diseases, including Parkinson's disease. The propensity of native proteins to form such amyloid fibril, both in vitro and in vivo, is highly sensitive to the surr ...

The nucleoid-associated protein EspR, a chromosome organizer, has pleiotropic effects on expression of genes associated with cell wall function and pathogenesis in Mycobacterium tuberculosis. In particular, EspR binds to several sites upstream of the espAC ...

Giovanni Dietler

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Temperature-Controlled Assembly of High Ordered/Disordered Dodecylamine Layers on HOPG: Consequences for DNA Patterning

Supercoiling Induces Denaturation Bubbles in Circular DNA

Spatial organization of DNA sequences directs the assembly of bacterial chromatin by a nucleoid-associated protein

Force-distance curves by atomic force microscopy

Single-molecule force spectroscopy of a protein globule covalently bound to a calcite surface

FM-AFM constant height imaging and force curves: high resolution study of DNA-tip interactions

Active solubilization and refolding of stable protein aggregates by cooperative unfolding action of individual hsp70 chaperones

Atypical DNA recognition mechanism used by the EspR virulence regulator of Mycobacterium tuberculosis

Tightening of DNA knots by supercoiling facilitates their unknotting by type II DNA topoisomerases

A critical concentration of N-terminal pyroglutamylated amyloid beta drives the misfolding of Ab1-42 into more toxic aggregates

Stiffness Tomography by Atomic Force Microscopy

DNA-protein interactions explored by atomic force microscopy

Europium-Doped CsPbI2Br for Stable and Highly Efficient Inorganic Perovskite Solar Cells

Upstream Binding of Idling RNA Polymerase Modulates Transcription Initiation from a Nearby Promoter

Stable -Synuclein Oligomers Strongly Inhibit Chaperone Activity of the Hsp70 System by Weak Interactions with J-domain Co-chaperones

Coherent fluorescence resonance energy transfer: Construction of nonlocal multiparticle entangled states and quantum computing

Observation and Modification of the Surface of Some Organic Crystals by Means of Atomic Force Microscopy

Scanning Near-field Optical Microscopy-based Study of Local Dynamics of Receptor-Ligand Interactions at the Single Molecule Level

Effects of sedimentation, microgravity, hydrodynamic mixing and air-water interface on alpha-synuclein amyloid formation

Functional Dissection of Intersubunit Interactions in the EspR Virulence Regulator of Mycobacterium tuberculosis