Dicarboxylic Oligopeptide Bolaamphiphiles:  Proton-Triggered Self-Assembly of Microtubes with Loose Solid Surfaces

Abstract

A new family of oligopeptide-based bolaamphiphiles, glycylglycine-(1a-h), glycylglycylglycine-(2a-b), sarcosylsarcosine-(3), L-prolyl-L-proline-(4), glycylsarcosylsarcosine-( 5), and glycyl-L-prolyl-L-proline (6)based bolaamphiphiles with a dicarboxylic headgroup at each end, has been synthesized. The oligopeptide fragments were linked via amide bond to a long-chain R,ω-dicarboxylic acid as a hydrocarbon spacer. Self-assembling properties of these bolaamphiphiles in water have been studied by light and cryogenic temperature transmission electron microscopy, infrared spectroscopy, and pH titration. Only sodium or potassium salts (acid soap) of the bolaamphiphiles 1a, 1c, 1e, 2a, and 2b produced well-defined microtubes of 1-3-µm diameter with closed ends. All the tubes encapsulated a number of vesicular assemblies inside the aqueous compartment. The tube formation strongly depends on the connecting alkylene chain length, the alkylene even-odd carbon numbers, and constituent amino acid residues. Vectorial formation of acid-anion dimers and loose interpeptide hydrogen-bond networks are responsible for the microtube self-assembly. The atomic force microscopic observation of the microtube made of 1e revealed a distorted hexagonal arrangement of the headgroups on the surface. A self-assembling model and the tube formation mechanism are also discussed from the viewpoint of proton-triggered self-assembly.

Cu nanocrystal growth on peptide nanotubes by biomineralization: Size control of Cu nanocrystals by tuning peptide conformation

“…Details of this bolaamphiphile peptide monomer synthesis and the nanotube self-assembly have been described (50,54,55). The HG12 peptide was sequenced by Applied Biosystems Peptide Synthesizer 432A and purified by using Beckman 110 HPLC equipped with a C-18 reverse-phase chromatographic column at the Center for Study of Gene Structure and Function, City University of New York.…”

Effect of the side chain of N-acyl amino acid surfactants on micelle formation: An isothermal titration calorimetry study

“…N-Acyl amino acid surfactants, which are anionic amino acid-type surfactants, are useful both from industrial and domestic viewpoints, because of their biodegradability and low toxicity. Further, concern over the effect of the residues on aggregation has been growing since it was reported that some amphiphiles containing peptide groups like N-acyl amino acid, self-assembled to form various highly-organized nanometer-scale structures [20][21][22][23]. Since micelle formation is one of the most basic of aggregation behavior, it is useful to investigate the effect of amino acid residues for the purpose of understanding the higher self-assembly behavior, including that of polypeptides [24][25][26][27].…”

Multifunctional, biocompatible and pH-responsive carbon nanotube- and graphene oxide/tectomer hybrid composites and coatings

“…55 To the contrary, although from the same family, oligoglycine-based bolaamphiphiles that possess carboxylic (instead of amino) head groups do not assemble as tectomers but as vesicles and microtubes, because of the electrostatic repulsion between ionized carboxylic groups. 56,57 Tectomers have the ability to form extensive, surface adaptive, ultrathin coatings and, on top of that, are biocompatible and may act as biointerfaces. This, together with the atomically smooth rigid 2D structure (which is very unique to this system), pH-responsive nature and chemical reactivity of their terminal amino groups are attributes that make tectomers very appealing as platforms for engineering novel functional layered biomaterials.…”