Influence of End-Capping on the Self-Assembly of Model Amyloid Peptide Fragments
(2011) In The Journal of Physical Chemistry Part B 115(9). p.2107-2116- Abstract
- The influence of charge and aromatic stacking interactions on the self-assembly of a series of four model amyloid peptides has been examined. The four model peptides are based on the KLVFF motif from the amyloid beta peptide, A beta(16-20) extended at the N terminus with two P-alanine residues. We have studied NH2-beta A beta AKLVFF-COOH (FF), NH2-beta A beta AKLVF-COOH (F), CH3CONH-beta A beta AKLVFF-CONH2 (CapF), and CH3CONH-beta A beta AKLVFF-CONH2 (CapFF). The former two are uncapped (net charge +2) and differ by one hydrophobic phenylalanine residue; the latter two are the analogous capped peptides (net charge +1). The self-assembly characteristics of these peptides are remarkably different and strongly dependent on concentration. NMR... (More)
- The influence of charge and aromatic stacking interactions on the self-assembly of a series of four model amyloid peptides has been examined. The four model peptides are based on the KLVFF motif from the amyloid beta peptide, A beta(16-20) extended at the N terminus with two P-alanine residues. We have studied NH2-beta A beta AKLVFF-COOH (FF), NH2-beta A beta AKLVF-COOH (F), CH3CONH-beta A beta AKLVFF-CONH2 (CapF), and CH3CONH-beta A beta AKLVFF-CONH2 (CapFF). The former two are uncapped (net charge +2) and differ by one hydrophobic phenylalanine residue; the latter two are the analogous capped peptides (net charge +1). The self-assembly characteristics of these peptides are remarkably different and strongly dependent on concentration. NMR shows a shift from carboxylate to carboxylic acid forms upon increasing concentration. Saturation transfer measurements of solvent molecules indicate selective involvement of phenylalanine residues in driving the self-assembly process of CapFF due presumably to the effect of aromatic stacking interactions. FTIR spectroscopy reveals beta-sheet features for the two peptides containing two phenylalanine residues but not the single phenylalanine residue, pointing again to the driving force for self-assembly. Circular dichroism (CD) in dilute solution reveals the polyproline II conformation, except for F which is disordered. We discuss the relationship of this observation to the significant pH shift observed for this peptide when compared the calculated value. Atomic force microscopy and cryogenic-TEM reveals the formation of twisted fibrils for CapFF, as previously also observed for FF. The influence of salt on the self-assembly of the model beta-sheet forming capped peptide CapFF was investigated by FTIR Cryo-TEM reveals that the extent of twisting decreases with increased salt concentration, leading to the formation of flat ribbon structures. These results highlight the important role of aggregation-induced pK(a) shifts in the self-assembly of model beta-sheet peptides. (Less)
Please use this url to cite or link to this publication:
https://lup.lub.lu.se/record/1869149
- author
- Castelletto, Valeria ; Hamley, Ian W. ; Cenker, Celen LU ; Olsson, Ulf LU ; Adamcik, Jozef ; Mezzenga, Raffaele ; Miravet, Juan F. ; Escuder, Beatriu and Rodriguez-Llansola, Francisco
- organization
- publishing date
- 2011
- type
- Contribution to journal
- publication status
- published
- subject
- in
- The Journal of Physical Chemistry Part B
- volume
- 115
- issue
- 9
- pages
- 2107 - 2116
- publisher
- The American Chemical Society (ACS)
- external identifiers
-
- wos:000287833000023
- scopus:79952274356
- pmid:21309578
- ISSN
- 1520-5207
- DOI
- 10.1021/jp111168s
- language
- English
- LU publication?
- yes
- id
- 8a6cf878-6362-4349-ae79-a65f6c379e37 (old id 1869149)
- date added to LUP
- 2016-04-01 13:10:13
- date last changed
- 2022-02-19 03:23:54
@article{8a6cf878-6362-4349-ae79-a65f6c379e37,
abstract = {{The influence of charge and aromatic stacking interactions on the self-assembly of a series of four model amyloid peptides has been examined. The four model peptides are based on the KLVFF motif from the amyloid beta peptide, A beta(16-20) extended at the N terminus with two P-alanine residues. We have studied NH2-beta A beta AKLVFF-COOH (FF), NH2-beta A beta AKLVF-COOH (F), CH3CONH-beta A beta AKLVFF-CONH2 (CapF), and CH3CONH-beta A beta AKLVFF-CONH2 (CapFF). The former two are uncapped (net charge +2) and differ by one hydrophobic phenylalanine residue; the latter two are the analogous capped peptides (net charge +1). The self-assembly characteristics of these peptides are remarkably different and strongly dependent on concentration. NMR shows a shift from carboxylate to carboxylic acid forms upon increasing concentration. Saturation transfer measurements of solvent molecules indicate selective involvement of phenylalanine residues in driving the self-assembly process of CapFF due presumably to the effect of aromatic stacking interactions. FTIR spectroscopy reveals beta-sheet features for the two peptides containing two phenylalanine residues but not the single phenylalanine residue, pointing again to the driving force for self-assembly. Circular dichroism (CD) in dilute solution reveals the polyproline II conformation, except for F which is disordered. We discuss the relationship of this observation to the significant pH shift observed for this peptide when compared the calculated value. Atomic force microscopy and cryogenic-TEM reveals the formation of twisted fibrils for CapFF, as previously also observed for FF. The influence of salt on the self-assembly of the model beta-sheet forming capped peptide CapFF was investigated by FTIR Cryo-TEM reveals that the extent of twisting decreases with increased salt concentration, leading to the formation of flat ribbon structures. These results highlight the important role of aggregation-induced pK(a) shifts in the self-assembly of model beta-sheet peptides.}},
author = {{Castelletto, Valeria and Hamley, Ian W. and Cenker, Celen and Olsson, Ulf and Adamcik, Jozef and Mezzenga, Raffaele and Miravet, Juan F. and Escuder, Beatriu and Rodriguez-Llansola, Francisco}},
issn = {{1520-5207}},
language = {{eng}},
number = {{9}},
pages = {{2107--2116}},
publisher = {{The American Chemical Society (ACS)}},
series = {{The Journal of Physical Chemistry Part B}},
title = {{Influence of End-Capping on the Self-Assembly of Model Amyloid Peptide Fragments}},
url = {{http://dx.doi.org/10.1021/jp111168s}},
doi = {{10.1021/jp111168s}},
volume = {{115}},
year = {{2011}},
}