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Improved preparation of amyloid-β peptides using DBU as Nα-Fmoc deprotection reagent

journal contribution
posted on 2001-09-01, 00:00 authored by A K Tickler, Colin BarrowColin Barrow, J D Wade
Previous studies have shown the amyloid peptides, Abeta 1-40/42, to be exceptionally difficult to assemble by Fmoc-solid phase peptide synthesis due to the high hydrophobicity of the C-terminal segment and resulting on-resin aggregation. We found that the use of the stronger and more efficient base, DBU, at a concentration of 2% in DMF for Nalpha-Fmoc deprotection allowed substantially improved continuous flow solid phase assembly of the model peptide Abeta 29-40/42 fragments. This suggested that, at least for these sequences, incomplete deprotection was a greater problem than incomplete amino acid acylation. This base was then used during the synthesis of both Abeta 1-40 and Abeta 1-42, up to and including Ser8, from which point 20% piperidine in DMF was utilized so as to avoid potential aspartimide formation at Asp7. By this means, the deprotection efficiency through the difficult C-terminal portion of the sequence was much improved and resulted in increased availability of terminal amino groups for acylation. This simple strategy that obviates the need for special conditions significantly improved crude peptide quality and allowed considerable facilitation of subsequent purification.

History

Journal

Journal of peptide science

Volume

7

Issue

9

Pagination

488 - 494

Publisher

John Wiley & Sons

Location

Chichester, Eng.

ISSN

1075-2617

Language

eng

Publication classification

C1.1 Refereed article in a scholarly journal

Copyright notice

2001, European Peptide Society & John Wiley & Sons