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Simultaneous assessment of conformation and aggregation of β‐amyloid peptide using electrospray ionization mass spectrometry
Author(s) -
Chen X. G.,
Brining Sheryl K.,
Nguyen Viet Q.,
Yergey Alfred L.
Publication year - 1997
Publication title -
the faseb journal
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.709
H-Index - 277
eISSN - 1530-6860
pISSN - 0892-6638
DOI - 10.1096/fasebj.11.10.9271367
Subject(s) - chemistry , random coil , electrospray ionization , peptide , monomer , mass spectrometry , ionization , mass spectrum , envelope (radar) , analytical chemistry (journal) , electrospray , ion , crystallography , chromatography , circular dichroism , organic chemistry , polymer , biochemistry , radar , telecommunications , computer science
Electrospray ionization mass spectrometry was used to study conformation and aggregation of the synthetic β‐amyloid peptide, residues 1–40 (βA4), as a function of concentration and sample aging. All mass spectra showed a major envelope of peaks corresponding to charge states of 7–3 of the monomeric form of βA4. In addition, weaker envelopes of peaks corresponding to charge states of dimeric, trimeric, and tetrameric βA4 species were seen under gentle ionization conditions. The average charge state of the envelope associated with the monomeric form decreased by ca. 0.5 z as samples were aged, indicating that the relatively open form (likely random coil) of the peptide was modified into the more compact form (likely β‐sheet) as a function of sample aging. The aggregate forms became weaker and ultimately were absent both in the more dilute solutions and in aged aliquots of the concentrated sample. These aggregates were interpreted as assemblies of the random coil form. We interpret our inability to see an ion envelope that can be associated with aggregates of the β‐sheet form to be a consequence of the presumed very compact nature of this form. A model for the formation of βA4 fibrils is proposed and discussed.—Chen, X. G., Brining, S. K., Nguyen, V. Q., Yergey, A. L. Simultaneous assessment of conformation and aggregation of β‐amyloid peptide using electrospray ionization mass spectrometry. FASEB J. 11, 817–823 (1997)