[NMR paper] Resolution of Oligomeric Species during the Aggregation of A?1-40 Using 19F NMR.

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Resolution of Oligomeric Species during the Aggregation of A?1-40 Using 19F NMR.

Resolution of Oligomeric Species during the Aggregation of A?1-40 Using 19F NMR.

Biochemistry. 2013 Feb 27;

Authors: Suzuki Y, Brender JR, Soper MT, Krishnamoorthy J, Zhou Y, Ruotolo BT, Kotov NA, Ramamoorthy A, Marsh EN

Abstract
In the commonly used nucleation-dependent model of protein aggregation, aggregation proceeds only after a lag phase in which the concentration of energetically unfavorable nuclei reaches a critical value. The formation of intermediate species prior to aggregation can be difficult to detect by current spectroscopic techniques. By using real-time 19F NMR along with other techniques, we are able to show that multiple oligomeric species can be detected during the lag phase of A?1-40 fiber formation, consistent with a complex mechanism of aggregation. At least 6 types of oligomers can be detected by 19F NMR. These include the reversible formation of large ?-sheet oligomer immediately after solubilization at high peptide concentration; a small oligomer that forms transiently during the early stages of the lag phase; and 4 spectroscopically distinct forms of oligomers with molecular weights between ~30-100 kDa that appear during the later stages of aggregation. The ability to resolve individual oligomers and track their formation in real-time should prove fruitful in understanding the aggregation of amyloidogenic proteins and in isolating potentially toxic non-amyloid oligomers.


PMID: 23445400 [PubMed - as supplied by publisher]



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