Assembly of π-Stacking Helical Peptides into a Porous and Multivariable Proteomimetic Framework

Abstract

The evolution of proteins from simpler, selfassembled peptides provides a powerful blueprint for the design of complex synthetic materials. Previously, peptide−metal frameworks using short sequences (≤3 residues) have shown great promise as proteomimetic materials that exhibit sophisticated capabilities. However, their development has been hindered due to few variable residues and restricted choice of side-chains that are compatible with metal ions. Herein, we developed a noncovalent strategy featuring π-stacking bipyridyl residues to assemble much longer peptides into crystalline frameworks that tolerate even previously incompatible acidic and basic functionalities and allow an unprecedented level of pore variations. Single-crystal X-ray structures are provided for all variants to guide and validate rational design. These materials exhibit hallmark proteomimetic behaviors such as guest-selective induced fit and assembly of multimetallic units. Significantly, we demonstrate facile optimization of the framework design to substantially increase affinity toward a complex organic molecule.

Porous Supramolecular Assembly of Pentiptycene-Containing Gold(I) Complexes: Persistent Excited-State Aurophilicity and Inclusion-Induced Emission Enhancement

“…The emission quantum yield (Φ em ) is 2%, and the microsecond emission lifetime (τ em = 3.93 μs) reveals a phosphorescence character, attributable to the Au heavy atom effect. As indicated by the time-dependent density functional theory (TDDFT) calculations (Table S1), the long-wavelength absorption possesses a mixed character of the ligand-to-metal charge transfer (LMCT) 1 [π (PhCC) → 6s/6p­(Au)] and interligand charge-transfer (LLCT) 1 [π (PhCC) → π*­(Ph ip NC)] transitions, but the triplet-state emission is ascribed to the more localized intraligand (IL) phenylacetylide ππ*] state with mixing of the LMCT state. The latter is consistent with the ∼1020, ∼1570, and ∼2100 cm –1 vibrational spacing, attributable to the phenyl ring deformation, phenyl ring stretching, and ethynylene stretching, respectively .…”

“…Supramolecular assembly is a powerful strategy for generating new collective properties (e.g., helicity and porosity) beyond the characteristics of individual molecules. − To construct a specific supramolecular entity, a predictable molecular assembly behavior based on the molecular structure is essential. However, the design of an extrinsic porous supramolecular framework remains to be a challenging task because the intermolecular interactions are much weaker than the coordination or covalent bonds in the well-established porous frameworks such as metal–organic frameworks and covalent organic frameworks .…”

Influence of Lipidation Pattern of the KR12 Fragment of Peptide LL-37 on Its Antibacterial and Hemolytic Activities

“…In PBS, the high salt concentration reduced the electrostatic repulsion between the peptide monomers by screening the positive charges on the amino acid side chains and facilitated the self-assembly. In the case of peptides XX and XXI , the higher tendency to self-assemble can be also attributed to the presence of the additional aromatic ring(s) and π-π stacking interactions [ 29 , 30 ]. However, taking into account that not all of the aromatic counterparts showed a tendency to self-assemble at a concentration of 0.15 mg/mL, it can be assumed that the increase in aromatic acid rigidity was additionally conducive to self-assembly.…”

Surfactant-Assisted Assembly of Dipeptide Forming a Broom-like Structure

“…The behavior of peptides, which can self-assemble into various nanostructures, has attracted much attention because of their applications in biomedical, bioengineering and drug production [ 4 , 5 , 6 , 7 , 8 ]. In contrast to other supramolecular structural motifs, the unique and desirable features of peptides include their chemical diversity, sequence-specific secondary structures, biomolecular recognition, high biocompatibility, and ease of synthesis [ 9 , 10 , 11 , 12 , 13 , 14 , 15 ]. As a minimal-recognition module, the dipeptide Phe-Phe (FF), which can easily assemble into various ordered structures, is the most studied because of its mechanical, electrical and optical properties [ 16 , 17 , 18 , 19 , 20 , 21 ].…”