scholarly journals The interplay of self-assembly and target binding in centrin 1 from Toxoplasma gondii

2021 ◽  
Author(s):  
Carolina Conter ◽  
Luca Bombardi ◽  
Marco Pedretti ◽  
Filippo Favretto ◽  
Adele Di Matteo ◽  
...  
Keyword(s):  
Toxoplasma Gondii ◽  
Self Assembly ◽  
Metal Binding ◽  
Hydrophobic Interactions ◽  
Structural Features ◽  
The Self ◽  
Intact Protein ◽  
Titration Calorimetry ◽  
Self Association ◽  
Target Binding

Centrins are conserved calcium (Ca2+)-binding proteins typically associated with centrosomes that have been implicated in several biological processes. In Toxoplasma gondii, a parasite that causes toxoplasmosis, three centrin isoforms have been recognized. We have recently characterized the metal binding and structural features of isoform 1 (TgCEN1), demonstrating that it possesses properties consistent with a role as a Ca2+ sensor and displays a Ca2+-dependent tendency to self-assemble. Herein, we expanded our studies, focusing on the self-association and target binding properties of TgCEN1 by combining biophysical techniques including dynamic light scattering, isothermal titration calorimetry, nuclear magnetic resonance, circular dichroism, and fluorescence spectroscopy. We found that the self-assembly process of TgCEN1 depends on different physicochemical factors, including Ca2+ concentration, temperature, and protein concentration, and is mediated by both electrostatic and hydrophobic interactions. The process is completely abolished upon removal of the first 21-residues of the protein and is significantly reduced in the presence of a binding target peptide derived from the human XPC protein (P17-XPC). Titration of P17-XPC to the intact protein and isolated domains showed that TgCEN1 possesses two binding sites with distinct affinities and Ca2+ sensitivity; a high-affinity site in the C-lobe which may be constitutively bound to the peptide and a low-affinity site in the N-lobe which is active only upon Ca2+ stimulus. Overall, our results suggest a specific mechanism of TgCEN1 for Ca2+-modulated target binding and support a N-to-C self-assembly mode, in which the first 21-residues of one molecule likely interact with the C-lobe of the other.

scholarly journals Rules for the self-assembly of ESCRT-III on endosomes

2021 ◽  
Author(s):  
Simon Sprenger ◽  
Simona M. Migliano ◽  
Florian Oleschko ◽  
Marvin Kobald ◽  
Michael Hess ◽  
...  
Keyword(s):  
Self Assembly ◽  
Hydrophobic Interactions ◽  
The Self ◽  
Amino Acid Residues ◽  
Lateral Expansion ◽  
Endosomal Sorting ◽  
Aaa Atpase ◽  
Charged Amino Acids ◽  
Membrane Budding ◽  
Positively Charged

ABSTRACTThe endosomal sorting complexes required for transport (ESCRT) mediate various membrane remodeling processes in cells by mechanism that are incompletely understood. Here we combined genetic experiments in budding yeast with site-specific cross-linking to identify rules that govern the self-assembly of individual ESCRT-III proteins into functional ESCRT-III complexes on endosomes. Together with current structural models of ESCRT-III, our findings suggest that, once nucleated, the growing Snf7 protofilament seeds the lateral co-assembly of a Vps24 - Vps2 heterofilament. Both Vps24 and Vps2 use positively charged amino acid residues in their helices α1 to interact with negatively charged amino acids in helix α4 of Snf7 subunits of the protofilament. In the Vps24 - Vps2 heterofilament, the two subunits alternate and interact with each other using hydrophobic interactions between helices α2/α3. The co-assembly of the Vps24 - Vps2 heterofilament restricts the lateral expansion of Snf7 protofilaments and leads the immediate recruitment of the AAA-ATPase Vps4. This self-assembly process of three ESCRT-III subunits results in the formation of a Snf7 protofilament and the co-assembly of a Vps24 - Vps2 heterofilament. This sets the stage for Vps4 recruitment and the subsequent ATP-driven dynamic self-organization of ESCRT-III / Vps4 assemblies and the ensuing membrane budding and scission events.

scholarly journals Self-assembly study of type I collagen extracted from male Wistar Hannover rat tail tendons

2020 ◽  
Vol 24 (1) ◽  
Author(s):  
Jeimmy González-Masís ◽  
Jorge M. Cubero-Sesin ◽  
Simón Guerrero ◽  
Sara González-Camacho ◽  
Yendry Regina Corrales-Ureña ◽  
...  
Keyword(s):  
Regenerative Medicine ◽  
Self Assembly ◽  
Type I Collagen ◽  
Ph Effect ◽  
The Self ◽  
Titration Calorimetry ◽  
Type I ◽  
Self Assembling ◽  
Functional Features ◽  
Rat Tail

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

scholarly journals Controlling the Self-Assembly of Biomolecules into Functional Nanomaterials through Internal Interactions and External Stimulations: A Review

Nanomaterials ◽  
2019 ◽  
Vol 9 (2) ◽  
pp. 285 ◽  
Author(s):  
Li Wang ◽  
Coucong Gong ◽  
Xinzhu Yuan ◽  
Gang Wei
Keyword(s):  
Self Assembly ◽  
Electrostatic Interactions ◽  
Materials Science ◽  
Hydrophobic Interactions ◽  
The Self ◽  
Functional Nanomaterials ◽  
Light Stimulation ◽  
Dna Base ◽  
Wide Range ◽  
Structure And Functions

Biomolecular self-assembly provides a facile way to synthesize functional nanomaterials. Due to the unique structure and functions of biomolecules, the created biological nanomaterials via biomolecular self-assembly have a wide range of applications, from materials science to biomedical engineering, tissue engineering, nanotechnology, and analytical science. In this review, we present recent advances in the synthesis of biological nanomaterials by controlling the biomolecular self-assembly from adjusting internal interactions and external stimulations. The self-assembly mechanisms of biomolecules (DNA, protein, peptide, virus, enzyme, metabolites, lipid, cholesterol, and others) related to various internal interactions, including hydrogen bonds, electrostatic interactions, hydrophobic interactions, π–π stacking, DNA base pairing, and ligand–receptor binding, are discussed by analyzing some recent studies. In addition, some strategies for promoting biomolecular self-assembly via external stimulations, such as adjusting the solution conditions (pH, temperature, ionic strength), adding organics, nanoparticles, or enzymes, and applying external light stimulation to the self-assembly systems, are demonstrated. We hope that this overview will be helpful for readers to understand the self-assembly mechanisms and strategies of biomolecules and to design and develop new biological nanostructures or nanomaterials for desired applications.

scholarly journals Interplay between hydrophilic and hydrophobic interactions in the self-assembly of a gemini amphiphilic pseudopeptide: from nano-spheres to hydrogels

2012 ◽  
Vol 48 (16) ◽  
pp. 2210 ◽  
Author(s):  
Jenifer Rubio ◽  
Ignacio Alfonso ◽  
M. Isabel Burguete ◽  
Santiago V. Luis
Keyword(s):  
Self Assembly ◽  
Hydrophobic Interactions ◽  
The Self

Influence of structural features on the self-assembly of short ionic oligopeptides

2010 ◽  
Vol 48 (4) ◽  
pp. 889-897 ◽  
Author(s):  
Andrea Desii ◽  
Federica Chiellini ◽  
Celia Duce ◽  
Lisa Ghezzi ◽  
Susanna Monti ◽  
...  
Keyword(s):  
Self Assembly ◽  
Structural Features ◽  
The Self

The self-association of the cyclotide kalata B2 in solution is guided by hydrophobic interactions

Biopolymers ◽  
2013 ◽  
Vol 100 (5) ◽  
pp. 453-460 ◽  
Author(s):  
K. Johan Rosengren ◽  
Norelle L. Daly ◽  
Peta J. Harvey ◽  
David J. Craik
Keyword(s):  
Hydrophobic Interactions ◽  
The Self ◽  
Self Association

scholarly journals Erratum: The self-association of the cyclotide kalata B2 in solution is guided by hydrophobic interactions

Biopolymers ◽  
2013 ◽  
Vol 102 (1) ◽  
pp. 136-136
Author(s):  
K. Johan Rosengren ◽  
Norelle L. Daly ◽  
Peta J. Harvey ◽  
David J. Craik
Keyword(s):  
Hydrophobic Interactions ◽  
The Self ◽  
Self Association

scholarly journals Hydrophobic interactions control the self-assembly of DNA and cellulose

2021 ◽  
Vol 54 ◽  
Author(s):  
Björn Lindman ◽  
Bruno Medronho ◽  
Luís Alves ◽  
Magnus Norgren ◽  
Lars Nordenskiöld
Keyword(s):  
Hydrogen Bonding ◽  
Self Assembly ◽  
Hydrophobic Interactions ◽  
Double Helix ◽  
The Self ◽  
Biological Macromolecules ◽  
Helix Formation ◽  
Assembly Features ◽  
Pertinent Information ◽  
Net Charges

Abstract Desoxyribosenucleic acid, DNA, and cellulose molecules self-assemble in aqueous systems. This aggregation is the basis of the important functions of these biological macromolecules. Both DNA and cellulose have significant polar and nonpolar parts and there is a delicate balance between hydrophilic and hydrophobic interactions. The hydrophilic interactions related to net charges have been thoroughly studied and are well understood. On the other hand, the detailed roles of hydrogen bonding and hydrophobic interactions have remained controversial. It is found that the contributions of hydrophobic interactions in driving important processes, like the double-helix formation of DNA and the aqueous dissolution of cellulose, are dominating whereas the net contribution from hydrogen bonding is small. In reviewing the roles of different interactions for DNA and cellulose it is useful to compare with the self-assembly features of surfactants, the simplest case of amphiphilic molecules. Pertinent information on the amphiphilic character of cellulose and DNA can be obtained from the association with surfactants, as well as on modifying the hydrophobic interactions by additives.

scholarly journals Systematic study of the structural parameters affecting the self-assembly of cyclic peptide–poly(ethylene glycol) conjugates

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 ◽  
...  
Keyword(s):  
Amino Acids ◽  
Self Assembly ◽  
Cyclic Peptides ◽  
Cyclic Peptide ◽  
Hydrophobic Interactions ◽  
Structural Parameters ◽  
The Self ◽  
Poly Ethylene Glycol ◽  
Self Assembling ◽  
Poly Ethylene

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.

scholarly journals Determination of the secondary structure of selected melittin analogues with different haemolytic activities

1994 ◽  
Vol 299 (2) ◽  
pp. 587-591 ◽  
Author(s):  
E Pérez-Payá ◽  
R A Houghten ◽  
S E Blondelle
Keyword(s):  
Amino Acid ◽  
Secondary Structure ◽  
Structural Features ◽  
The Self ◽  
Single Amino Acid ◽  
Haemolytic Activity ◽  
Phospholipid Membrane ◽  
Hydrophobic Residues ◽  
Self Association

In earlier studies, we have reported that minor modifications in the amino acid sequence of melittin result in dramatic changes in its biological activity. In the current study, we have investigated the secondary structure of melittin analogues with either increased or decreased haemolytic activity in order to further our understanding of the structural features involved in the binding and/or insertion of peptides into a phospholipid membrane from solution. This was accomplished by analysing the c.d. spectra of the analogues in solutions of various ionic strength and, separately, in the presence of micelles. These studies permit the assessment of the effect of small sequence modifications (i.e. single amino acid omission or substitution) on the self-association-induced secondary structure of melittin in aqueous solution, as well as its binding affinity to micelles. It was found that amphipathicity, as well as interchain distances and the orientation of hydrophobic residues, were involved in the induction of stabilized structures.

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