Gas-phase conformation can have an influence on peptide fragmentation

International audienceIn the context of proteome analysis, matrix-assisted laser desorption/ionization mass spectrometry (MALDI-MS) can fulfil the two tasks of primary structure verification and protein identification. As an illustration of the first of these tasks, the sequence of Eschericha coli isoleucyl-tRNA synthetase, a protein with 15 reported sequence conflicts, has been established by means of MALDI mass mapping. The identification of mitochondrial proteins participating in a yeast supramolecular complex exhibiting NADH dehydrogenase activity highlights the performances of MALDI-MS for the second task. The spectral suppression phenomenon occurring for complex peptide mixtures analysed by MALDI is discussed, as well as the role of post-source decay analysis for confident protein identification

Analysis of the solidification and microstructure of two aluminium alloys reinforced with TiB₂ particles

Two aluminium alloys with 6 wt% TiB2 particles are studied for applications where increased wear resistance and mechanical strength at high temperature are required. The incorporation of hard ceramic particles has a strong influence on the microstructure and properties of the alloys. TiB2 particles play an important role in the nucleation of the different phases of the alloys during solidification, and in the reduction of grain size and porosity. The solidification patterns of Al-Si7Mg0.3 + TiB2 (6 wt%) and Al-Cu5MgTi + TiB2 (6 wt%) materials are compared to their corresponding non-reinforced alloys, and the microstructures are analyzed