Secondary structure of rhBMP-2 in a protective biopolymeric carrier material

Efficient delivery of growth factors is one of the great challenges of tissue engineering. Polyelectrolyte multilayer films (PEM) made of biopolymers have recently emerged as an interesting carrier for delivering recombinant human bone morphogenetic protein 2 (rhBMP-2 noted here BMP-2) to cells in a matrix-bound manner. We recently showed that PEM made of poly(l-lysine) and hyaluronan (PLL/HA) can retain high and tunable quantities of BMP-2 and can deliver it to cells to induce their differentiation in osteoblasts. Here, we investigate quantitatively by Fourier transform infrared spectroscopy (FTIR) the secondary structure of BMP-2 in solution as well as trapped in a biopolymeric thin film. We reveal that the major structural elements of BMP-2 in solution are intramolecular β-sheets and unordered structures as well as α-helices. Furthermore, we studied the secondary structure of rhBMP-2 trapped in hydrated films and in dry films since drying is an important step for future applications of these bioactive films onto orthopedic biomaterials. We demonstrate that the structural elements were preserved when BMP-2 was trapped in the biopolymeric film in hydrated conditions and, to a lesser extent, in dry state. Importantly, its bioactivity was maintained after drying of the film. Our results appear highly promising for future applications of these films as coatings of biomedical materials, to deliver bioactive proteins while preserving their bioactivity upon storage in dry state.This work was supported by the French Ministry of Research through an ANR-EmergenceBIO grant (ANR-09-EBIO-012-01), by the European Commission (FP7 program) via a European Research Council starting grant (BIOMIM, GA 259370), and by GRAVIT (081012_FIBIOS). C.P. is grafetul to IUF for financial support

Tethered Bilayer lipid membranes (tBLMs) : interest and applications for biological membrane investigations.

International audienceBiological membranes play a central role in the biology of the cell. They are not only the hydrophobic barrier allowing separation between two water soluble compartments but also a supra-molecular entity that has vital structural functions. Notably, they are involved in many exchange processes between the outside and inside cellular spaces. Accounting for the complexity of cell membranes, reliable models are needed to acquire current knowledge of the molecular processes occurring in membranes. To simplify the investigation of lipid/protein interactions, the use of biomimetic membranes is an approach that allows manipulation of the lipid composition of specific domains and/or the protein composition, and the evaluation of the reciprocal effects. Since the middle of the 80's, lipid bilayer membranes have been constantly developed as models of biological membranes with the ultimate goal to reincorporate membrane proteins for their functional investigation. In this review, after a brief description of the planar lipid bilayers as biomimetic membrane models, we will focus on the construction of the tethered Bilayer Lipid Membranes, the most promising model for efficient membrane protein reconstitution and investigation of molecular processes occurring in cell membranes

Model membranes to shed light on the biochemical and physical properties of ezrin/radixin/moesin.

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Mitochondrial creatin kinase interaction with heterogeneous monolayers : Effect on lipid lateral organization

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Mitochondrial creatine kinase adsorption to biomimetic membranes : a Langmuir monolayer study.

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A new functional membrane protein microarray based on tethered phospholipid bilayers

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Mitochondrial creatine kinase binding to phospholipid monolayers induces cardiolipin segregation

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Design of glycosyltransferase inhibitors targeting human O-GlcNAc transferase (OGT)

International audienceInhibition of glycosyltransferases requires the design of neutral inhibitors to allow cell permeation in contrast to their natural dianionic substrates. O-GlcNAc transferase (OGT) is a key enzyme involved in dynamic glycosylation of cytosolic and nuclear proteins in competition with phosphorylation. Designing OGT inhibitors is of prime interest for the better understanding of its biological implications. Introduction of a pyridine moiety as a pyrophosphate surrogate was evaluated, which provided moderate in vitro inhibition of OGT. Docking studies highlighted some key features for the binding of the designed inhibitors to the catalytic site of OGT where the carbohydrate moiety did not occupy its natural position but rather turned away and pointed to the solvent outside the catalytic pocket. Further investigation with cellular assays did not provide inhibition of OGT. This lack of OGT inhibition was rationalized with a permeation assay which revealed the sequestration of the inhibitors at the membrane