Exploring the potential of molecular spectroscopy for the detection of post-translational modifications of a stressed biopharmaceutical protein

Background: Proteins are biomolecules that consist of sequences of amino acids (primary structure) which can further interact and cause the backbone to fold into more complex structures (secondary and tertiary structures). Any chemical alterations of the molecules after the translation of the messenger RNA code into a protein primary sequence are known as post-translational modifications (PTMs). PTMs may affect the protein’s functionality; thus it is necessary to identify them. PTMs of particular interest to the pharmaceutical industry include deamidation, oxidation, deglycosylation and isomerization, which may occur due to environmental stressors. However, they have proved challenging to identify quickly. Electronic and vibrational spectroscopies have proved valuable tools for studying higher-order structure and stability of proteins. Materials & Methods: In this work, circular dichroism (CD), infrared absorbance (IR) and Raman spectroscopies were applied to characterize antibody (mAb NIP 228) PTMs as a result of different stressors. Mass spectrometry was used to confirm the identity of modifications including the targeted ones. Room temperature CD showed that the secondary structure was the same after all treatments, and temperature-controlled CD showed how protein stability was affected by modifications. Both Raman and IR analysis detected small differences between the reference and deglycosylated proteins, and clearly indicated the presence of other PTMs. Conclusion: This work required some novel computational approaches to pre–process Raman and IR spectra and a review of the band assignments for proteins existing in the literature.

Synthesis, crystal structure and structure–property relations of strontium orthocarbonate, Sr2CO4

Carbonates containing CO4 groups as building blocks have recently been discovered. A new orthocarbonate, Sr2CO4 is synthesized at 92 GPa and at a temperature of 2500 K. Its crystal structure was determined by in situ synchrotron single-crystal X-ray diffraction, selecting a grain from a polycrystalline sample. Strontium orthocarbonate crystallizes in the orthorhombic crystal system (space group Pnma) with CO4, SrO9 and SrO11 polyhedra as the main building blocks. It is isostructural to Ca2CO4. DFT calculations reproduce the experimental findings very well and have, therefore, been used to predict the equation of state, Raman and IR spectra, and to assist in the discussion of bonding in this compound.

Distortion Induced Structural Characteristics of Ba2R2/3TeO6 (R =Y, Gd, Tb, Dy, Ho, Er, Tm, Yb and Lu) Double Perovskites and its Multifunction Optical Properties in Lighting and Ratiometric Temperature Sensing

Group theoretical predictions obtained from Raman and IR spectra emphasize the structure of B-site ordered double perovskites Ba2R2/3TeO6 (R =Y, Gd, Tb, Dy, Ho, Er, Tm, Yb, Lu) with ubiquitous...

New amorphous nanophosphors obtained by evaporation of silicates and germanates REE

Amorphous nanophosphors have been produced by pulsed electron beam evaporation of bulk phosphors of rare earth elements (REE) silicates and germanates with oxyapatite structure activated with europium. The processes of crystallization of amorphous nanopowders (NP) have been studied by differential scanning calorimetry and thermogravimetry (40–1400°C) methods. A modification of the Raman and IR spectra of the samples was found when the particle size decreased from bulk to nanostate due to insignificant polymerization of Si(Ge)O4 tetrahedra. The spectral and luminescence characteristics of the bulk samples as well as nanoamorphous samples have been examined. It was established that Eu3+ forms two types of optical centers. Upon the transition of Sr2Gd8(SiO4)6O2:Eu3+ phosphor from bulk state to nanostate during laser excitation, the luminescence intensity of Eu3+ ions increases 10 times. Blue and white amorphous nanophosphors have been obtained for the first time by evaporation of Ca2M8(SiO4)6O2:Eu (M=Y, Gd) and Ca2La8(GeO4)O2:Eu phosphors. Radiation reduction of ions Eu3+→Eu2+ in electron beam has been presumably found.