Matrix-assisted laser desorption ionization hydrogen/deuterium exchange studies to probe peptide conformational changes

AbstractHydrogen/deuterium (H/D) exchange chemistry monitored by matrix-assisted laser desorption ionization time-of-flight (MALDI-TOF) mass spectrometry is used to study solution phase conformational changes of bradykinin, α-melanocyte stimulating hormone, and melittin as water is added to methanol-d4, acetonitrile, and isopropanol-d8 solutions. The results are interpreted in terms of a preference for the peptides to acquire more compact conformations in organic solvents as compared to the random conformations. Our interpretation is supported by circular dichroism spectra of the peptides in the same solvent systems and by previously published structural data for the peptides. These results demonstrate the utility of MALDI-TOF as a method to monitor the H/D exchange chemistry of peptides and investigations of solution-phase conformations of biomolecules

Vibrationally resolved photoelectron-spin-polarization spectroscopy of HI molecules

Böwering N, Salzmann M, Müller M, Klausing H-W, Heinzmann U. Vibrationally resolved photoelectron-spin-polarization spectroscopy of HI molecules. Physical Review, A: Atomic, Molecular and Optical Physics. 1992;45(1):R11-R14

Cloning, expression, characterisation and three-dimensional structure determination of Caenorhabditis elegans spermidine synthase

The polyamine synthesis enzyme spermidine synthase (SPDS) has been cloned from the model nematode Caenorhabditis elegans. Biochemical characterisation of the recombinantly expressed protein revealed a high degree of similarity to other eukaryotic SPDS with the exception of a low affinity towards the substrate decarboxylated S-adenosylmethionine (K-m = 110 mu M) and a less pronounced feedback inhibition by the second reaction product 5 '-methylthioadenosine (IC50 = 430 mu M). The C elegans protein that carries a nematode-specific insertion of 27 amino acids close to its N-terminus was crystallized, leading to the first X-ray structure of a dimeric eukaryotic SPDS. (c) 2005 Federation of European Biochemical Societies. Published by Elsevier B.V. All rights reserved