NR AXVY
AU Schmerr,M.J.; Baker,E.S.; Tang,K.; Bigelow,D.J.
TI Analysis of Monomer-Dimer Transition of Prion Peptides by ESI-IMS Mass Spectrometry
QU International Conference - Prion 2007 (26.-28.9.2007) Edinburgh International Conference Centre, Edinburgh, Scotland, UK - Book of Abstracts: Protein Misfolding P01.06
IA http://www.prion2007.com/pdf/Prion Book of Abstracts.pdf
PT Konferenz-Poster
AB
Progress in understanding the conformation changes that lead to refolding of the normal prion protein into the abnormal form has been elusive. Several regions within the prion protein have been suggested as possible sites responsible for the misfolding that occurs in the abnormal protein; these include regions near the amino terminus, the neurotoxic palindromic sequence, and helix 1. The conformation in these regions may be altered by changes in their micro environment. A new ESI-IMS-TOF mass spectrometer with enhanced sensitivity was used to detect these changes at the molecular level. This instrumentation combines electrophospray ionization (ESI) which allows the direct sampling of biomolecules out of a solution, ion mobility spectrometry (IMS) which is capable of separation of each biomolecule by shape, and mass spectrometry (MS) which determines the mass to charge (m/z) ratio for each. Synthetic prion peptides from the regions 89-1-3, 106-126 and 141-152 were analyzed by this instrument to examine structural changes occurring at different pHs.
Each prion peptide was dissolved in 1:1 (v/v) MeOH/H2O and directly infused into the ESI-IMS-TOF MS at a flow rate of 0.3µL/min and ionized in a positive ESI mode. The
ions were focused by a high pressure hourglass ion funnel and pulsed into an 88cm long drift cell filler with 4 Torr ultra pure N2 gas for the IMS separations. The ions were gently pulled through the N2 gas at a contant drift velocity by a weak electric field and allowed to separate based on the number of collisions they made with the drift gas.
After exiting the drift cell, the diffused ions were refocused by a secondary ion funnel and further analyzed by an orthogonal time-of-flight (TOF) MS to determine the m/z ratio of each.
We found that : i) peptide 89-103 exists in solution at all pHs as monomer only; ii) peptide 141-152 exists as dimer only; iii) peptide 106-126 exhibits both dimer and monomer species with a loss of monomer occurring at pH 9.0. The neurotoxic peptide 106-126 is the most sensitive to solution conditions that may be an early event in the refolding of the prion protein into the abnormal form.
AD M.J. Schmerr, Iowa State University, Ames Laboratory, USA; E.S. Baker, K. Tang, Pacific Northwest National Laboratories, Biological Sciences Division, USA; D.J. Bigelow, Pacific Northwest National Laboratories, Cell Biology and Biochemistry Group, USA
SP englisch
PO Schottland
EA pdf-Datei und Poster, das eine geänderte Autorenliste aufweist