Interaction of a pH-Responsive Designed Nanostructured Peptide with a Model Lipid Membrane (original) (raw)
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2012
fortunate to share good times and discussions with such great people. Also I thank Dr. Lijun Liu for his contributions and suggestions in the initial stages of this research. I am very thankful to Dr. Kenneth Hall for his support and professional recommendations and to Dr. Yin Qin Gao for serving on my committee before leaving Texas A&M University. I would like to thank the Theoretical and Computational Biophysics Group at the University of Illinois for kindly providing excellent open-source documentation and training information in computational biophysics topics through their web site. The greatest appreciation is reserved for my dear friend and mother, Edda Diaz; I am grateful for her sacrifices and for always expecting the best personal and professional achievements from me, while supporting my life with constant motivation. Her encouragement has been essential to be perseverant in pursuing my dreams and goals. Equally, I am grateful to my brother for his love and for always being responsible and caring. His intelligence and character make me proud and happy every day. Special thanks to my beloved best friend and husband, Diego Cristancho, for his unconditional support, patience and understanding. I find myself fortunate to have him in my life, his love and affection have been source of inspiration, strength and happiness. Finally, thanks to our families, friends, colleagues and the department faculty and staff for making my time at Texas A&M University a great experience. The doctoral program has been a rewarding experience in my professional and personal development.
In this tutorial review the process and applications of peptide self-assembly into nanotubes, nanospheres, nanofibrils, nanotapes, and other ordered structures at the nano-scale are discussed. The formation of well-ordered nanostructures by a process of self-association represents the essence of modern nanotechnology. Such self-assembled structures can be formed by a variety of building blocks, both organic and inorganic. Of the organic building blocks, peptides are among the most useful ones. Peptides possess the biocompatibility and chemical diversity that are found in proteins, yet they are much more stable and robust and can be readily synthesized on a large scale. Short peptides can spontaneously associate to form nanotubes, nanospheres, nanofibrils, nanotapes, and other ordered structures at the nano-scale. Peptides can also form macroscopic assemblies such as hydrogels with nano-scale order. The application of peptide building blocks in biosensors, tissue engineering, and the development of antibacterial agents has already been demonstrated.
On the design of supramolecular assemblies made of peptides and lipid bilayers
Journal of Peptide Science, 2014
Peptides confer interesting properties to materials, supramolecular assemblies and to lipid membranes and are used in analytical devices or within delivery vehicles. Their relative ease of production combined with a high degree of versatility make them attractive candidates to design new such products. Here, we review and demonstrate how CD-and solid-state NMR spectroscopic approaches can be used to follow the reconstitution of peptides into membranes and to describe some of their fundamental characteristics. Whereas CD spectroscopy is used to monitor secondary structure in different solvent systems and thereby aggregation properties of the highly hydrophobic domain of p24, a protein involved in vesicle trafficking, solid-state NMR spectroscopy was used to deduce structural information and the membrane topology of a variety of peptide sequences found in nature or designed. 15 N chemical shift solid-state NMR spectroscopy indicates that the hydrophobic domain of p24 as well as a designed sequence of 19 hydrophobic amino acid residues adopt transmembrane alignments in phosphatidylcholine membranes. In contrast, the amphipathic antimicrobial peptide magainin 2 and the designed sequence LK15 align parallel to the bilayer surface. Additional angular information is obtained from deuterium solid-state NMR spectra of peptide sites labelled with 2 H 3 -alanine, whereas 31 P and 2 H solid-state NMR spectra of the lipids furnish valuable information on the macroscopic order and phase properties of the lipid matrix. Using these approaches, peptides and reconstitution protocols can be elaborated in a rational manner, and the analysis of a great number of peptide sequences is reviewed. Finally, a number of polypeptides with membrane topologies that are sensitive to a variety of environmental conditions such as pH, lipid composition and peptide-to-lipid ratio will be presented. /journal/jpepsci 15 N-Leu23]-p24TMD. (F) Deconvolution of the spectra shown in E provides positiondependent quadrupolar splittings and the corresponding deuterium order parameters S CD. The p24TMD peptide causes a small increase in several of the POPC-d 31 order parameters. The estimated error bar is <0.004 for S CD , which fits within the outline of the symbols used in panel E.
Self-assembly of peptides to nanostructures
Organic & Biomolecular Chemistry, 2014
The formation of well-ordered nanostructures through self-assembly of diverse organic and inorganic building blocks has drawn much attention owing to their potential applications in biology and chemistry.
Peptide Self-Assembled Nanostructures: From Models to Therapeutic Peptides
Nanomaterials, 2022
Self-assembly is the most suitable approach to obtaining peptide-based materials on the nano- and mesoscopic scales. Applications span from peptide drugs for personalized therapy to light harvesting and electron conductive media for solar energy production and bioelectronics, respectively. In this study, we will discuss the self-assembly of selected model and bioactive peptides, in particular reviewing our recent work on the formation of peptide architectures of nano- and mesoscopic size in solution and on solid substrates. The hierarchical and cooperative characters of peptide self-assembly will be highlighted, focusing on the structural and dynamical properties of the peptide building blocks and on the nature of the intermolecular interactions driving the aggregation phenomena in a given environment. These results will pave the way for the understanding of the still-debated mechanism of action of an antimicrobial peptide (trichogin GA IV) and the pharmacokinetic properties of a pe...
Trends in Biotechnology, 2007
Self-assembly at the nanoscale is becoming increasingly important for the fabrication of novel supramolecular structures, with applications in the fields of nanobiotechnology and nanomedicine. Peptides represent the most favorable building blocks for the design and synthesis of nanostructures because they offer a great diversity of chemical and physical properties, they can be synthesized in large amounts, and can be modified and decorated with functional elements, which can be used in diverse applications. In this article, we review some of the most recent experimental advances in the use of nanoscale self-assembled peptide structures and the theoretical efforts aimed at understanding the microscopic determinants of their formation, stability and conformational properties. The combination of experimental observations and theoretical advances will be fundamental to fully realizing the biotechnological potential of peptide self-organization.
Control over Multiple Nano‐ and Secondary Structures in Peptide Self‐Assembly
Angewandte Chemie, 2021
Herein, we report the rich morphological and conformational versatility of a biologically active peptide (PEP-1), which follows diverse self-assembly pathways to form up to six distinct nanostructures and up to four different secondary structures through subtle modulation in pH, concentration and temperature. PEP-1 forms twisted b-sheet secondary structures and nanofibers at pH 7.4, which transform into fractal-like structures with strong b-sheet conformations at pH 13.0 or short disorganized elliptical aggregates at pH 5.5. Upon dilution at pH 7.4, the nanofibers with twisted bsheet secondary structural elements convert into nanoparticles with random coil conformations. Interestingly, these two selfassembled states at pH 7.4 and room temperature are kinetically controlled and undergo a further transformation into thermodynamically stable states upon thermal annealing: whereas the twisted b-sheet structures and corresponding nanofibers transform into 2D sheets with well-defined b-sheet domains, the nanoparticles with random coil structures convert into short nanorods with a-helix conformations. Notably, PEP-1 also showed high biocompatibility, low hemolytic activity and marked antibacterial activity, rendering our system a promising candidate for multiple bio-applications.
Symmetry-Directed Self-Organization in Peptide Nanoassemblies through Aromatic π–π Interactions
Journal of Physical Chemistry B, 2017
Almost all biological systems are assemblies of one or more biomolecules from nano to macro dimensions. Unlike inorganic molecules, peptide systems attune with the conceptual framework of aggregation models while they form nano-assemblies. Three significant recent theoretical models indicate that nucleation, end to end association and geometry of growth are determined primarily by size and electrostatics of individual basic building blocks. In this study, we put to test six model systems, differentially modulating the prominence of three design variables, namely aromatic π-π interactions, local electrostatics and overall symmetry of the basic building unit. Our results indicate that the crucial design elements in a peptide based nanoassembly are a) stable extended π-π interaction network b) size and c) overall symmetry of the basic building blocks. The six model systems represent all the design variables in the best way possible considering the complexity of a bio-molecule. The results provide important directives in deciding the morphology and crystallinity of peptide nano-assemblies.
ACS Omega, 2019
Probing the intermolecular interactions and local environments of self-assembled peptide nanostructures (SPNs) is crucial for a better understanding of the underlying molecular details of self-assembling phenomena. In particular, investigation of the hydration state is important to understand the nanoscale structural and functional characteristics of SPNs. In this report, we examined the local hydration environments of SPNs in detail to understand the driving force of the discrete geometric structural self-assembling phenomena for peptide nanostructures. Advanced electron paramagnetic resonance spectroscopy was used to probe the hydrogen bond formation and geometry as well as the hydrophobicity of the local environments at various spinlabeled sites in SPNs. The experimental results supplement the sparse experimental data regarding local structures of SPNs, such as the hydrogen bonding and the hydrophobicity of the local environment, providing important information on the formation of SPNs, which have immense potential for bioactive materials.