Search results for "Biophysics"

Structures of single, double and triple layers of lipids adsorbed on graphene: Insights from all-atom molecular dynamics simulations

2017

Abstract Non-covalent functionalization of graphene with phospholipids is a promising technique for biosensing applications and intracellular delivery of analytical probes and drugs. However, molecular details of the self-assembly of lipids on graphene surface is still poorly understood and hard to control. There is a clear lack of understanding of why various kinds of lipid aggregates can form on graphene. In the current work, we address this question by investigating equilibrium and dynamical properties of lipid layers adsorbed on graphene in water environment and in vacuum using all-atom Molecular Dynamics simulations. It is shown that a variety of lipid aggregates can form on top of gra…

Mass spectrometry for the study of protein-ligand interactions and supramolecular complexes: Application to an intrinsically disordered protein

2015

International audience

Numerical models contribute to expand the sweet taste chemical space

2021

The shell matrix and microstructure of the Ram's Horn squid: Molecular and structural characterization.

2020

20 pages; International audience; Molluscs are one of the most diversified phyla among metazoans. Most of them produce an external calcified shell, resulting from the secretory activity of a specialized epithelium of the calcifying mantle. This biomineralization process is controlled by a set of extracellular macromolecules, the organic matrix. In spite of several studies, these components are mainly known for bivalves and gastropods. In the present study, we investigated the physical and biochemical properties of the internal planispiral shell of the Ram's Horn squid Spirula spirula. Scanning Electron Microscope investigations of the shell reveal a complex microstructural organization. The…

Calcium, calmodulin-dependent protein phosphorylation in Neurospora crassa

1984

Abstract A calcium, calmodulin-dependent protein kinase activity has been partially purified by calmodulin-Sepharose affinity chromatography from the soluble fraction of Neurospora crassa . The phosphorylated peptide has an apparent molecular mass on SDS-polyacrylamide gel of 47 kDa. The apparent half maximal phosphorylation is obtained after 1.5 min at 30° C in the presence of calcium and calmodulin. The apparent half maximal activation of the phosphorylation is obtained at 1 μM calcium, and 0.1 or 0.2 μM calmodulin from bovine brain or Neurospora , respectively. The 32 P incorporation is enhanced about 10-fold by calmodulin.

Characterization of a novel selenium methyltransferase from freshwater bacteria showing strong similarities with the calicheamicin methyltransferase

2004

A novel group of Se-methyltransferases is presented. The genetic determinant, named mmtA, which revealed this group was isolated from selenite and selenate-resistant freshwater bacteria. E. coli expressing mmtA and grown with a Se supplement emitted dimethyl selenide (DMSe) and dimethyl diselenide (DMDSe). Phylogenetic analysis divided MmtA-like bacterial sequences into two clusters, one grouping MmtA with S- and O-methyltransferases, and one grouping UbiE C-methyltransferases. Se methylation by some of these MmtA phyletic neighbours was investigated.

Decoding sweet taste from chemical structures

2019

International audience

New technologies getting informations on repartition, orientation and identification of biomolecules on SPR chip

2008

We present herein an original approach, consisting to lead in parallel a global analysis (SPR) and nanoscale characterizations (AFM, mass spectrometry, TOF-SIMS) of bio-molecules on the biochip surface. The questions we want to answer concern especially the organization, orientation and identification of immobilized and captured biomolecules. In order to characterize the sensing layer in terms of molecular structure and orientation, we engaged a SPR-TOF SIMS first set of experiments (collaboration: Pr Aoyagi, Japan). Our results demonstrated that analysis of orientation of the immobilized cytochrome b5 is possible (ref2&3) and help to optimize and develop our sensing layer. We also recently…

Technological innovation around protein and cell biochip for diagnosis: a translational research from nanoworld to patient

2009

International audience; A great challenge in biosensors and diagnosis devices relies on the way to reconstitute relevant biological mechanisms on surface of the biochips and which analytical tools are convenient to provide accurate and rapid information on the structures and function of molecules attached to this surface. A better control in the realization of biochips can be obtained in combining different complementary approaches while always keeping in mind the biological key point. Researches in CLIPP are focused towards this objective. Conception, realization and characterization of protein and cell chips are presented. We detail different strategies of materials engineering1,2,3, chem…

Cell imaging connected with protein mapping to investigate glyphosate induced toxicity on human keratinocytes

2009

During the skin ageing which is accelerated by environmental factors, the generated reactive oxygen species make unstable the "proliferation/differentiation/apoptosis" coupling of epidermal cells. A biochemical study, previously realized on human keratinocyte cultures treated by a pesticide, glyphosate, allowed the validation of an in vitro model of skin ageing. In this work, we propose to study the loss of HaCaT cell integrity appearing after this chemical induced-oxidative stress. An original approach, combining a micro- to nanoscale cell characterization and analysis of fluctuating protein expression, is proposed: a) the exploration of cell growth and morphology through fluorescence and …