Self-Assembly of an alpha-Helical Peptide into a Crystalline Two-Dimensional Nanoporous Framework

• Type of Material: Article
• Authors: Elizabeth L. Magnotti, Emory University; Spencer A. Hughes, Emory University; Rebecca S. Dillard, Emory University; Shengyuan Wang, Emory University; Lillian Hough, Emory University; Arshad Karumbamkandathil, Emory University; Tianquan Lian, Emory University; Joseph S. Wall, Brookhaven National Laboratory; Xiaobing Zuo, Argonne National Laboratory; Elizabeth R. Wright, Emory University; Vincent Conticello, Emory University
• Language: English
• Date: 2016-12-21
• Publisher: American Chemical Society
• Publication Version: Author Accepted Manuscript (After Peer Review)
• Copyright Statement: © 2016 American Chemical Society.
• Final Published Version (URL): http://dx.doi.org/10.1021/jacs.6b06592
• Title of Journal or Parent Work: Journal of the American Chemical Society
• ISSN: 0002-7863
• Volume: 138
• Issue: 50
• Start Page: 16274
• End Page: 16282
• Grant/Funding Information: This study was supported in part by the Robert P. Apkarian Integrated Electron Microscopy Core (RPAIEMC), which is subsidized by the Emory College of Arts and Sciences and the Emory University School of Medicine and is one of the Emory Integrated Core Facilities.; The content is solely the responsibility of the authors and does not necessarily reflect the official views of the National Institutes of Health.; V.P.C. acknowledges financial support from NSF grants CHE-1012620 and CHE-1412580.; T.L. acknowledges the financial support from the National Science Foundation (CHE-1309817).; The electron microscopy data described here were gathered on either a JEOL JEM-2200FS 200 kV TEM (supported by a National Science Foundation Major Research Instrumentation Grant 0923395) or on a JEOL JEM-1400 120 kV TEM (supported by a National Institutes of Health Grant S10 RR025679).; E.R.W. acknowledges support from Emory University, Children’s Healthcare of Atlanta, the Georgia Research Alliance, the Center for AIDS Research at Emory University (P30 AI050409), the James B. Pendleton Charitable Trust, and NIH grant R01GM10454; Additional support was provided by the National Center for Advancing Translational Sciences of the National Institutes of Health under award number UL1TR000454.; This work benefited from the use of the A.P.S. funded by U.S. D.O.E. Office of Basic Energy Sciences, Division of Material Sciences, under contract W-31-109-Eng-38.
• Keywords: COILED-COIL ASSEMBLIES; COMPUTATIONAL DESIGN; COMPLEX NANOSHEET; ATP SYNTHASE; Science & Technology; PROTEIN NANOMATERIALS; SHEETS; Chemistry; Physical Sciences; DIMERIZATION DOMAIN; Chemistry, Multidisciplinary; ANGSTROM RESOLUTION STRUCTURE; PACKING ANGLE PREFERENCES; SUPRAMOLECULAR ORGANIC FRAMEWORK
• Research Categories: Chemistry, Biochemistry; Chemistry, General

Abstract

Sequence-specific peptides have been demonstrated to self-assemble into structurally defined nanoscale objects including nanofibers, nanotubes, and nanosheets. The latter structures display significant promise for the construction of hybrid materials for functional devices due to their extended planar geometry. Realization of this objective necessitates the ability to control the structural features of the resultant assemblies through the peptide sequence. The design of a amphiphilic peptide, 3FD-IL, is described that comprises two repeats of a canonical 18 amino acid sequence associated with straight α-helical structures. Peptide 3FD-IL displays 3-fold screw symmetry in a helical conformation and self-assembles into nanosheets based on hexagonal packing of helices. Biophysical evidence from TEM, cryo-TEM, SAXS, AFM, and STEM measurements on the 3FD-IL nanosheets support a structural model based on a honeycomb lattice, in which the length of the peptide determines the thickness of the nanosheet and the packing of helices defines the presence of nanoscale channels that permeate the sheet. The honeycomb structure can be rationalized on the basis of geometrical packing frustration in which the channels occupy defect sites that define a periodic superlat tice. The resultant 2D materials may have potential as materials for nanoscale transport and controlled release applications.