On-Chip Sample Preparation Using a ChipFilter Coupled to NanoLC-MS/MS for Bottom-Up Proteomics.

Sample preparation is a crucial step in bottom-up proteomics. Analytical performances of bottom-up proteomics can be improved by the miniaturization of sample preparation. Many microfluidic devices have been designed in the field of proteomics, but many of them are not capable of handling complex samples and do not integrate the processing and digestion steps.

DISCO synchrotron-radiation circular-dichroism endstation at SOLEIL.

The new synchrotron-radiation circular-dichroism (SRCD) endstation on the UV-visible synchrotron beamline DISCO has been commissioned at the SOLEIL synchrotron. The design has been focused on preservation of a high degree of linear polarization at high flux and moderate resolving power covering the vacuum ultraviolet to visible spectral range (125-600 nm). The beam dimensions have been set to 4 mm × 4 mm at 1 nm bandwidth for lower sample degradation.

A yeast toxic mutant of HET-s amyloid disrupts membrane integrity.

Many studies have pointed out the interaction between amyloids and membranes, and their potential involvement in amyloid toxicity. Previously, we generated a yeast toxic amyloid mutant (M8) from the harmless amyloid protein by changing a few residues of the Prion Forming Domain of HET-s (PFD HET-s(218-289)) and clearly demonstrated the complete different behaviors of the non-toxic Wild Type (WT) and toxic amyloid (called M8) in terms of fiber morphology, aggregation kinetics and secondary structure. In this study, we compared the interaction of both proteins (WT and M8) with membrane models, as liposomes or supported bilayers.

Orientation of molecular groups of fibers in nonoriented samples determined by polarized ATR-FTIR spectroscopy.

A method based on polarized attenuated total reflection Fourier transform infrared (ATR-FTIR) spectroscopy is proposed for determining the infrared dichroic absorption ratio of a single fiber from a sample deposited flat on a germanium crystal without the requirement of fiber orientation. The method shows its efficiency on cellulose fibers of paper and has been applied to protein fibers (type I collagen and β-amyloid) and polysaccharide fibers (cellulose and starch). The method gives access to the dichroic ratio of strong absorptions bands, which is not easily accessible with conventional absorption techniques.

In vivo and in vitro analyses of toxic mutants of HET-s: FTIR antiparallel signature correlates with amyloid toxicity.

The folding and interactions of amyloid proteins are at the heart of the debate as to how these proteins may or may not become toxic to their host. Although little is known about this issue, the structure seems to be clearly involved with effects on molecular events. To understand how an amyloid may be toxic, we previously generated a yeast toxic amyloid (mutant 8) from the nontoxic HET-s((218-289)) prion domain of Podospora anserina.

Comparative studies of nontoxic and toxic amyloids interacting with membrane models at the air-water interface.

Many in vitro studies have pointed out the interaction between amyloids and membranes, and their potential involvement in amyloid toxicity. In a previous study, we generated a yeast toxic mutant (M8) of the harmless model amyloid protein HET-s((218-289)). In this study, we compared the self-assembling process of the nontoxic wild-type (WT) and toxic (M8) protein at the air-water interface and in interaction with various phospholipid monolayers (DOPE, DOPC, DOPI, DOPS and DOPG).