Two Dimensional Oblique Molecular Packing within a Model Peptide Ribbon Aggregate. Issue 14 (23rd June 2020)

• Record Type: Journal Article
• Authors: Kuczera, Stefan; Rüter, Axel; Roger, Kevin; Olsson, Ulf
• Is Part Of: Chemphyschem. Volume 21:Issue 14(2020)
• Page Start: 1519
• Page End: 1523
• Publication Date: 2020-06-23
• Subjects: aggregation -- flow alignment -- peptides -- structure elucidation -- X-ray diffraction; Chemistry, Physical and theoretical -- Periodicals; 541.05
• DOI: 10.1002/cphc.201901126
• Languages: English
• ISSNs: 1439-4235

Abstract

Abstract: A10 K (A=alanine, K=lysine) model peptides self‐assemble into ribbon‐like β ‐sheet aggregates. Here, we report an X‐ray diffraction investigation on a flow‐aligned dispersion of these self‐assembly structures. The two‐dimensional wide‐angle X‐ray scattering pattern suggests that peptide pack in a two‐dimensional oblique lattice, essentially identical to the crystalline packing of polyalanine, An (for n >4). One side of the oblique unit cell, corresponding to the anti‐parallel β ‐sheet, is oriented along the ribbon's axis. Together with recently published small angle X‐ray scattering data of the same system, this work thus yields a detailed description of the self‐assembled ribbon aggregates, down to the molecular length scale. Notably, our results highlight the importance of the crystalline peptide packing within its self‐assembly aggregates, which is often neglected. Abstract : X‐ray diffraction of flow aligned A10 K ribbon aggregates (alignment indi‐ cated by birefringence) results in an oriented diffraction pattern. Based on this pattern a 2D oblique lattice as the internal crystalline structure is proposed for the aggregates.