Self-Assembly Effects of Cyclic Peptide Dimers: Molecular Modeling Study

2007 ◽  
Vol 353-358 ◽  
pp. 2257-2260
Author(s):  
Jing Chuan Zhu ◽  
Jie Cheng ◽  
Bo Liu

The cyclic peptides can self-assemble into β-sheet like antiparallel tubular ensembles through intermolecular hydrogen-bonding interaction. Under the self-assembling effects of the dimer subunits, various aggregate properties may alter with the change of the structure. The relationship between the property and structure of ensembles is extremely important for designing new nanostructures. Molecular mechanics (MM) and molecular dynamics (MD) were employed to investigate the structure and property of single dimer and dimer-ensemble from cyclo-[D-Phe-(1R, 3S)-γ-Acc]3. Results reveal that the single dimer cannot adsorb CHCl3 molecule into its cavity, while the two-dimer ensemble can do. It suggests that the self-assembled cyclic peptide nanotube from the dimer-ensemble may act as the transport channel of CHCl3 molecules.

Soft Matter ◽  
2018 ◽  
Vol 14 (30) ◽  
pp. 6320-6326 ◽  
Author(s):  
Edward D. H. Mansfield ◽  
Matthias Hartlieb ◽  
Sylvain Catrouillet ◽  
Julia Y. Rho ◽  
Sophie C. Larnaudie ◽  
...  

Self-assembling cyclic peptides (CP) consisting of amino acids with alternating d- and l-chirality form nanotubes by hydrogen bonding, hydrophobic interactions, and π–π stacking in solution.


Molecules ◽  
2019 ◽  
Vol 24 (6) ◽  
pp. 1084 ◽  
Author(s):  
Shaoming Jin ◽  
Zhongyao Du ◽  
Pengjie Wang ◽  
Huiyuan Guo ◽  
Hao Zhang ◽  
...  

Folic acid has been widely introduced into nano-drug delivery systems to give nanoparticle-targeted characteristics. However, the poor water solubility of folic acid may hinder the exploitation of its ability to load antineoplastic drugs. In the present study, we designed a new folate derivative (FA-2-DG) synthesized from folic acid and 2-Deoxyglucose (2-DG). The aim of this study was to evaluate the self-assembly characteristics of FA-2-DG, and its ability of loading cisplatin. The critical micelle concentration was 7.94 × 10−6 mol L−1. Fourier transform infrared spectroscopy indicated that hydrogen bonding interaction is a main driving force for the self–assembly of FA-2-DG. The particle was stable in pure water or 0.5% bovine serum albumin dispersions. By forming a coordination bond, the particles assembled from FA-2-DG can load cisplatin. The loading efficiency was maximal when the molar ratio of FA-2-DG to cisplatin was 2:1.


2017 ◽  
Vol 19 (29) ◽  
pp. 19032-19042 ◽  
Author(s):  
Z. Faidon Brotzakis ◽  
Mascha Gehre ◽  
Ilja K. Voets ◽  
Peter G. Bolhuis

From right to left: three distinct growth mechanisms of a pentamer to a hexamer putative antifreeze cyclic peptide nanotube.


2015 ◽  
Vol 57 (1) ◽  
pp. 62-78
Author(s):  
N. THAMWATTANA

Recently, organic nanostructures have attracted much attention, and amongst them peptide nanotubes are of interest in many fields of application including medicine and nanobiotechnology. Peptide nanotubes are formed by self-assembly of cyclic peptides with alternating L- and D-amino acids. Due to their biodegradability, flexible design and easy synthesis, many applications have been proposed such as artificial transmembrane ion channels, templates for nanoparticles, mimicking pore structures, nanoscale testing tubes, biosensors and carriers for targeted drug delivery. The mechanisms of an ion, a water molecule and an ion–water cluster entering into a peptide nanotube of structure cyclo[(-D-Ala-L-Ala-)$_{4}$] are explored here. In particular, the Lennard-Jones potential and a continuum approach are employed to determine three entering mechanisms: (i) through the tube open end, (ii) through a region between each cyclic peptide ring and (iii) around the edge of the tube open end. The results show that while entering the nanotube by method (i) is possible, an ion or a molecule requires initial energy to overcome an energetic barrier to be able to enter the nanotube through positions (ii) and (iii). Due to its simple structure, the D-, L-Ala cyclopeptide nanotube is chosen in this model; however, it can be easily extended to include more complicated nanotubes.


2020 ◽  
Vol 27 (9) ◽  
pp. 923-929
Author(s):  
Gaurav Pandey ◽  
Prem Prakash Das ◽  
Vibin Ramakrishnan

Background: RADA-4 (Ac-RADARADARADARADA-NH2) is the most extensively studied and marketed self-assembling peptide, forming hydrogel, used to create defined threedimensional microenvironments for cell culture applications. Objectives: In this work, we use various biophysical techniques to investigate the length dependency of RADA aggregation and assembly. Methods: We synthesized a series of RADA-N peptides, N ranging from 1 to 4, resulting in four peptides having 4, 8, 12, and 16 amino acids in their sequence. Through a combination of various biophysical methods including thioflavin T fluorescence assay, static right angle light scattering assay, Dynamic Light Scattering (DLS), electron microscopy, CD, and IR spectroscopy, we have examined the role of chain-length on the self-assembly of RADA peptide. Results: Our observations show that the aggregation of ionic, charge-complementary RADA motifcontaining peptides is length-dependent, with N less than 3 are not forming spontaneous selfassemblies. Conclusion: The six biophysical experiments discussed in this paper validate the significance of chain-length on the epitaxial growth of RADA peptide self-assembly.


Soft Matter ◽  
2020 ◽  
Vol 16 (28) ◽  
pp. 6599-6607 ◽  
Author(s):  
Pijush Singh ◽  
Souvik Misra ◽  
Nayim Sepay ◽  
Sanjoy Mondal ◽  
Debes Ray ◽  
...  

The self-assembly and photophysical properties of 4-nitrophenylalanine (4NP) are changed with the alteration of solvent and final self-assembly state of 4NP in competitive solvent mixture and are dictated by the solvent ratio.


2021 ◽  
Author(s):  
Bharti Koshti ◽  
Ramesh Singh ◽  
Vivekshinh Kshtriya ◽  
Shanka Walia ◽  
Dhiraj Bhatia ◽  
...  

<p>.<br></p><p>The self-assembly of single amino acids is very important topic of research since there are plethora of diseases like phenylketonuria, tyrosinemia, hypertryptophanemia, hyperglycinemia, cystinuria and maple syrup urine disease to name a few which are caused by the accumulation or excess of amino acids. These are in-born errors of metabolisms (IEM’s) which are caused due to the deficiency of enzymes involved in catabolic pathways of these enzymes. Hence, it is very pertinent to understand the fate of these excess amino acids in the body and their self-assembling behaviour at molecular level. From the previous literature reports it may be surmised that the single amino acids like Phenylalanine, Tyrosine, Tryptophan, Cysteine and Methionine assemble to amyloid like structures, and hence have important implications in the pathophysiology of IEM’s like phenylketonuria, tyrosinemia, hypertryptophanemia, cystinuria and hypermethioninemia respectively. In this manuscript we report the self-assembly of lysine hydrocholride to fiber like structures in deionized water. It could be observed that lysine assemble to globular structures in fresh condition and then gradually changes to fiber like morphologies by self-association over time after 24 hours. These fibers gradually change to tubular morphologies after 3 day followed by fractal irregular morphologies in 10 and 15 days respectively. Notably, lysine exists as positively charged amino acid at physiological pH and the amine groups in lysine remain protonated. Hence, the self-assembling properties of lysine hydrochloride in deionized water is also pertinent and give insights into the fate of this amino acid in body in case it remains unmetabolized. Further, MTT assays were done to analyse the toxicities of these aggregates and the assay suggest their cytotoxic nature on SHSY5Y neural cell lines. Hence, the aggregation of lysine may be attributed to the pathological symptoms caused in diseases like hyperlysinemia which is associated with the neurological problems like seizures and short-term memory as observed in case of amyloid diseases like Parkinson’s and Alzheimer’s to name a few.</p>


RSC Advances ◽  
2014 ◽  
Vol 4 (58) ◽  
pp. 30654-30657 ◽  
Author(s):  
Rie Wakabayashi ◽  
Yuko Abe ◽  
Noriho Kamiya ◽  
Masahiro Goto

New GALA-related peptide amphiphiles were designed and the influence of their self-assembling propensity and the secondary structure on the membrane permeability was studied.


2020 ◽  
Vol 24 (1) ◽  
Author(s):  
Jeimmy González-Masís ◽  
Jorge M. Cubero-Sesin ◽  
Simón Guerrero ◽  
Sara González-Camacho ◽  
Yendry Regina Corrales-Ureña ◽  
...  

Abstract Background Collagen, the most abundant protein in the animal kingdom, represents a promising biomaterial for regenerative medicine applications due to its structural diversity and self-assembling complexity. Despite collagen’s widely known structural and functional features, the thermodynamics behind its fibrillogenic self-assembling process is still to be fully understood. In this work we report on a series of spectroscopic, mechanical, morphological and thermodynamic characterizations of high purity type I collagen (with a D-pattern of 65 nm) extracted from Wistar Hannover rat tail. Our herein reported results can be of help to elucidate differences in self-assembly states of proteins using ITC to improve the design of energy responsive and dynamic materials for applications in tissue engineering and regenerative medicine. Methods Herein we report the systematic study on the self-assembling fibrillogenesis mechanism of type I collagen, we provide morphological and thermodynamic evidence associated to different self-assembly events using ITC titrations. We provide thorough characterization of the effect of pH, effect of salts and protein conformation on self-assembled collagen samples via several complementary biophysical techniques, including circular dichroism (CD), Fourier Transform infrared spectroscopy (FTIR), differential scanning calorimetry (DSC), atomic force microscopy (AFM), scanning electron microscopy (SEM), dynamic mechanical thermal analysis (DMTA) and thermogravimetric analysis (TGA). Results Emphasis was made on the use of isothermal titration calorimetry (ITC) for the thermodynamic monitoring of fibrillogenesis stages of the protein. An overall self-assembly enthalpy value of 3.27 ± 0.85 J/mol was found. Different stages of the self-assembly mechanism were identified, initial stages take place at pH values lower than the protein isoelectric point (pI), however, higher energy release events were recorded at collagen’s pI. Denatured collagen employed as a control exhibited higher energy absorption at its pI, suggesting different energy exchange mechanisms as a consequence of different aggregation routes. Graphical abstract


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