Structures of Helical β-Tapes and Twisted Ribbons:  The Role of Side-Chain Interactions on Twist and Bend Behavior

• Published in: Nano letters Vol. 3; no. 11; pp. 1475 - 1479
• Main Authors: Fishwick, Colin W. G, Beevers, Andrew J, Carrick, Lisa M, Whitehouse, Conor D, Aggeli, Amalia, Boden, Neville
• Format: Journal Article
• Language: English
• Published: Washington, DC American Chemical Society 01.11.2003
• Subjects: Aminoacids, peptides. Hormones. Neuropeptides; Analytical, structural and metabolic biochemistry; Biological and medical sciences; Fundamental and applied biological sciences. Psychology; Proteins
• ISSN: 1530-6984; 1530-6992
• DOI: 10.1021/nl034095p

Molecular Dynamics (MD) simulations have been used to obtain a molecular insight into the origins of the twist, bend, and helix pitch of the tape-like and ribbon (double tape)-like β-sheet aggregates formed by the self-assembling peptides P11-I (CH3CO-QQRQQQQQEQQ-NH2) and P11-II (CH3CO-QQRFQWQFEQQ-NH2). P11-II differs from P11-I in that glutamines at positions 4, 6, and 8 have been substituted for F, W, and F, and this gives rise to left-handed helicoidal tapes having a significantly shorter helix pitch. The presence of these hydrophobic residues also enhances the cross-tape attractive forces in P11-II ribbons, which foreshortens the helix pitch.