| title: | Further improvement of the acceleration-deceleration negative ion kinetic energy focusing method for registering high-resolution ICR mass spectra of deprotonated biomolecular ions |
|---|---|
| reg no: | ETF5134 |
| project type: | Estonian Science Foundation research grant |
| subject: |
1.3. Physics 1.6. Physical, Analytical and Inorganic Chemistry 2.7. Biotechnology, Food and Drink Technology |
| status: | completed |
| institution: | Institute of Chemical Physics and Biophysics |
| head of project: | Rein Pikver |
| duration: | 01.01.2002 - 31.12.2004 |
| description: | The determination of the structure of biomolecules and the indentification of their fragments by sequencing requires precise determination of molecular weight, which can only be achieved through high isotopic resolution. It is known that minor changes in protein structure can induce major changes in organisms. Isotopic resolution combined with isotopic substitution enables to study minute changes in the structure of biomolecules. ICR MS (ion cyclotron resonance mass spectrometry) together with MALDI (matrix assisted laser desorption ionization) methods are best suited for achieving isotopic resolution for both light and heavy ions. The construction an ICR MS spectrometer, based on our original acceleration-deceleration method for focusing kinetic energies of the MALDI-generated ions together with an original ICR cell design, was finished in the NICPB in 1997 and, from the on, has been used for registering positive ions isotopic high-resolution mass spectra.This year the acceleration-deceleration (AD) method for focusing ion kinetic energies in MALDI-FTICR mass spectrometry has been successfully applied to negative ions. By means of delayed acceleration and deceleration, the initial kinetic energies of the MALDI-produced deprotonated ions distributed over a broad energy range, were equalized and then decelerated to register the negative ion mass spectra with low potentials on the trapping plates. From the study all the available literature about the mass spectra of peptides and proteins we can draw the conclusion that isotopic high-resolution mass spectra of the MALDI-generated deprotonated ions of peptide substance P and protein bovine insulin B-chain were registered for the first time. In our experimentsthe mass resolutions 77 000 and 51 000 respectively for substance P (deprotonated mass 1345.720 Da) and bovine insulin B-chain (deprotonated mass 3492.64 Da) were obtained. The samples were prepared by dried droplet method on a stainless steel sample holder using DHB as a matrix for substance P and DHBs for bovine insulin B-chain. The preliminary experiments have shown the great potentialities our acceleration-deceleration method in registering negative ions isotopic high-resolution mass spectra. Therefore the further improvement of the methodology and apparatus within the framework of this grant would certainly improve the prospects of investigation the structure of biomolecules. |
| project group | ||||
|---|---|---|---|---|
| no | name | institution | position | |
| 1. | Rein Pikver | .National Institute of Chemical Physics and Biophysics | Senior Research Scientist | |
| 2. | Juhan Subbi | NICPB | Sen.Res.Scien. | |