[Abstract Title]. - Society for Neuroscience

Authors: N. NEMIEBOKA 1 , S. THOMAS 2 , Y. WAN 3 , Z. LIAO 2 , J. MCLAURIN 4 , *A.
YANG 3 ;
1 Program in Oncology, 2 Dept. of Radiation Oncology, 3 Greenebaum Cancer Ctr., Univ.
Maryland, Baltimore, Baltimore, MD; 4 Ctr. for Resaech in Neurodegenerative Dis., Univ. of
Toronto, Toronto, ON, Canada
Abstract: In this study, we have developed a novel electrospray ionization mediated high
throughput mass spectrometry-based platform to address the role of various small molecules in
modulating the dynamic assembly of amyloid peptide (Aß). By coupling a capillary ultra high
pressure HPLC system (UPLC) to either a triple quadrupole or a high resolution and high mass
accuracy orbitrap mass spectrometer, we are able to detect the assembly of Aß-ligand complexes
in solution at the low femtomole to attomole range, which provides a drastic improvement in the
sensitivity of our detection in comparison to other traditional solution-based binding and
biophysical approaches. In contrast to most MALDI-TOF mass spectrometry based methods,
examination of the charge distribution of both Aß and Aß-ligand complexes using ESI and gas
phase fractionation mass spectrometry preserves the structure of Aß-ligand complexes in
solution under their physiological condition.
To further determine the specificity of Aß-ligand complexes, we have also implemented topdown
and collision induced dissociation mass spectrometry approaches. Our preliminary study
demonstrates that by introducing several different types of gas phase fragmentation inside the
collision cell of the mass spectrometer we are able to measure the binding stoichiometry of the
Aß1-42-scyllo-inositol complex. Furthermore, we have demonstrated that scyllo-inositol
preferentially binds to Aß1-42 rather than Aß1-40 under our conditions. Finally, by using a series
of newly developed computational tools (both commercial and in-house) coupled with the
sequencing capability of tandem mass spectrometry, we are able to specifically demonstrate the
role of metal ions, such as copper, in modulating both the oxidation and structure of histidine
residues within Aß molecules.
Disclosures: N. Nemieboka, None; S. Thomas, None; Y. Wan, None; Z. Liao, None; J.
McLaurin, None; A. Yang , None.
Poster
243. Abeta Assembly and Deposition
Time: Sunday, November 16, 2008, 1:00 pm - 5:00 pm
Program#/Poster#: 243.11/L1
Topic: C.01.b. Abeta assembly and deposition
Title: Products of amyloid precursor protein metabolism are associated with mitochondria in
synaptic fields