Elementary Building Blocks of Self-Assembled Peptide Nanotubes

Abstract

In the world of biology, "self-assembly" is the ability of biological entities to interact with one another to form supramolecular structures. One basic group of self-assembled structures is peptide nanotubes (PNTs). However, the self-assembly mechanism, with its special characteristics, is not yet fully understood. An exceptional quantum-confined approach is shown here for the self-assembly mechanism in bio-inspired materials. We found the elementary building block of the studied PNT, which is self-assembled from short peptides composed of two phenylalanine residues, to be 0D-quantum-confined (can be related to confinement in 3D), also called a quantum dot (QD). This elementary building block can further self-assemble to a PNT formation. It has been observed that the assembly process of dots to tubes and the disassembly process of tubes to dots are reversible. We further show that a similar dipeptide can also self-assemble to a QD-like structure, with different dimensions. The presented peptide QD structures are nanometer-sized structures, with pronounced exciton effects, which may promote the use of an entirely new kind of organic QDs.

Could tyrosine and tryptophan serve multiple roles in biological redox processes?

“…The UniProtKB/Swiss-Prot database indicates that P450s are rich in aromatic amino acids: 90% of the sequences in the P450 family (956 sequences) have above-average occurrence of Phe residues; and 68% of the sequences have more Trp residues than average. Phe residues are unlikely to participate as real intermediates in ET reactions, but their role in enhanced superexchange coupling for long-range ET remains unresolved [46][47][48]. Cytochrome P450 BM3 (CYP102A1) is frequently used as a soluble surrogate for human microsomal P450 s [44].…”

Bioorganic nanodots for non-volatile memory devices

“…These d-spacings are consistent with the crystalline structure of the FF tube formation 26 and coincide with XRD of the PND (this latter XRD were obtained by powder-XRD of PNDs aggregates and not from single PND as in here). 12 The lateral size distribution of the FF PND that was estimated from the TEM images is 2.4 ± 0.6 nm (Fig. 1(c)).…”

“…Recently we have found that in anhydrous conditions the tubes can disassemble into stable building blocks of peptide nanodots (PNDs). 12 Thus, the nm-scaled (∼2 nm in diameter) PND architecture opens new opportunities for the integration of FF-based structures in bio-electronics devices.…”

“…The size distribution is similar to what we previously found for the FF PNDs (of 2.1 nm). 12 Though earlier mass-and secondary ion mass-spectrometries suggested that the PND is composed from a dimer of FF, 12 there is no purposed structure for the FF PND yet. An upper bound estimate for the number of molecules in a PND can be obtained by taking the crystalline molecular density as a limit.…”

Low-molecular-weight metabolite systems chemistry

“…Recently, nanotechnology research revealed that peptides can self-assemble into peptide nanotubes by a mechanism that is not yet understood fully. These peptide nanotubes can be components of metallic/semiconductor-organic frameworks (BioMOFs) ( Figure 6C) (Amdursky et al, 2010). Consequently, we may assume that peptides can form biosemiconductors in vivo too.…”