This Article Full Text Full Text (PDF) Supplemental A correction has been published All Versions of this Article: biophysj.105.063875v1 89/6/4139    most recent Alert me when this article is cited Alert me if a correction is posted Services Similar articles in this journal Similar articles in PubMed Alert me to new issues of the journal Download to citation manager Citing Articles Citing Articles via Google Scholar Google Scholar Articles by Goncharov, V. A. Search for Related Content PubMed PubMed Citation Articles by Goncharov, V. A.

Mass Spectroscopic Analysis of Sup35NM Prion Polymerization

Whitehead Institute for Biomedical Research, Cambridge, Massachusetts 02142

Correspondence: Address reprint requests to Vladimir A. Goncharov, Tel.: 617-452-2632; Fax: 617-258-1966; E-mail: goncharov{at}wi.mit.edu.

Sup35NM, the prion determining domain of the protein responsible for the yeast prion phenomenon [], has become a powerful model for studying key processes in amyloid-related human diseases. One of these processes is a conformational conversion of soluble precursor protein into insoluble fibrillar structures. In this study, we created a set of Sup35NM mutants and used proteolytic digestion coupled with mass spectroscopy to monitor local structure of the protein during polymerization. Experimental data were compared to a network model and showed that during the conformational conversion residue Arg-28 became highly protected from cleavage, residue Arg-98 remained partially solvent exposed, and residues between 28 and 98 showed an intermediate degree of protection. In addition, we found that a distinct subset of proteolytic polypeptides spanning 28–98 residues segment spontaneously formed stable dimers. This finding suggests that the [29–98] region is the key interacting region of Sup35NM responsible for amyloid conversion.