Liquid chromatography and electron-capture dissociation in Fourier transform ion cyclotron resonance mass spectrometry

Liq. sepn. methods in combination with electrospray mass spectrometry as well as the recently introduced fragmentation method electron capture dissocn. (ECD) have become powerful tools in proteomics research. This paper presents the results of the first successful attempts to combine liq. chromatog. (LC) and Fourier transform ion cyclotron resonance mass spectrometry (FTICRMS) with ECD in the anal. of a mixt. of std. peptides and of a bovine serum albumin tryptic digest. A novel electron injection system provided conditions for ECD sufficient to yield extensive sequence information for the most abundant peptides in the mixts. on the time-scale of the chromatog. sepn. The results suggest that LC/ECD-FTICRMS can be employed in the characterization of peptides in enzymic digests of proteins or protein mixts. and identify and localize posttranslational modifications. [on SciFinder (R)

Localized changes in the structural stability of myoglobin upon adsorption onto silica particles, as studied with hydrogen/deuterium exchange mass spectrometry

A new method is presented for monitoring the conformational stability of various parts of a protein that is physically adsorbed onto nanometer-sized silica particles. The method employs hydrogen/deuterium (H/D) exchange of amide hydrogens, a process that is extremely sensitive to structural features of proteins. The resulting mass increase is analyzed with Fourier transform ion cyclotron resonance (FTICR) mass spectrometry. Higher structural specificity is obtained by enzymatically cleaving the adsorbed proteins prior to mass spectrometric analysis. The mass increases of four peptic fragments of myoglobin are followed as a function of the H/D exchange time. The four peptic fragments cover 90% of the myoglobin structure. Two of the peptic fragments, located in the middle of the myoglobin sequence and close to the heme group, do not show any adsorption-induced changes in their structural stability, whereas the more stable C- and N-terminal fragments are destabilized. Interestingly, for the N-terminal fragment, comprising residues 1-29, two distinct and equally large conformational populations are observed. One of these populations has a stability similar to that in solution (-23 kJ/mol), whereas the other population is highly destabilized upon adsorption (-11 kJ/mol)