scholarly journals Conformational Preferences and Antiproliferative Activity of Peptidomimetics Containing Methyl 1′-Aminoferrocene-1-carboxylate and Turn-Forming Homo- and Heterochiral Pro-Ala Motifs

2021 ◽  
Vol 22 (24) ◽  
pp. 13532
Author(s):  
Monika Kovačević ◽  
Mojca Čakić Semenčić ◽  
Kristina Radošević ◽  
Krešimir Molčanov ◽  
Sunčica Roca ◽  
...  
Keyword(s):  
Biological Function ◽  
Clonogenic Assay ◽  
Conformational Flexibility ◽  
Peptide Backbone ◽  
X Ray ◽  
Structural Modifications ◽  
Conformational Preferences ◽  
Biological Potential ◽  
Viability Study ◽  
Natural Peptides

The concept of peptidomimetics is based on structural modifications of natural peptides that aim not only to mimic their 3D shape and biological function, but also to reduce their limitations. The peptidomimetic approach is used in medicinal chemistry to develop drug-like compounds that are more active and selective than natural peptides and have fewer side effects. One of the synthetic strategies for obtaining peptidomimetics involves mimicking peptide α-helices, β-sheets or turns. Turns are usually located on the protein surface where they interact with various receptors and are therefore involved in numerous biological events. Among the various synthetic tools for turn mimetic design reported so far, our group uses an approach based on the insertion of different ferrocene templates into the peptide backbone that both induce turn formation and reduce conformational flexibility. Here, we conjugated methyl 1′-aminoferrocene-carboxylate with homo- and heterochiral Pro-Ala dipeptides to investigate the turn formation potential and antiproliferative properties of the resulting peptidomimetics 2–5. Detailed spectroscopic (IR, NMR, CD), X-ray and DFT studies showed that the heterochiral conjugates 2 and 3 were more suitable for the formation of β-turns. Cell viability study, clonogenic assay and cell death analysis showed the highest biological potential of homochiral peptide 4.

scholarly journals In-depth analysis of subclass-specific conformational preferences of IgG antibodies

IUCrJ ◽  
2015 ◽  
Vol 2 (1) ◽  
pp. 9-18 ◽  
Author(s):  
Xinsheng Tian ◽  
Bente Vestergaard ◽  
Matthias Thorolfsson ◽  
Zhiru Yang ◽  
Hanne B. Rasmussen ◽  
...  
Keyword(s):  
Small Angle ◽  
Rational Design ◽  
Biological Function ◽  
Scattering Data ◽  
Variable Regions ◽  
X Ray ◽  
X Ray Scattering ◽  
Conformational Preferences ◽  
Depth Analysis ◽  
Ray Scattering

IgG subclass-specific differences in biological function andin vitrostability are often referred to variations in the conformational flexibility, while this flexibility has rarely been characterized. Here, small-angle X-ray scattering data from IgG1, IgG2 and IgG4 antibodies, which were designed with identical variable regions, were thoroughly analysed by the ensemble optimization method. The extended analysis of the optimized ensembles through shape clustering reveals distinct subclass-specific conformational preferences, which provide new insights for understanding the variations in physical/chemical stability and biological function of therapeutic antibodies. Importantly, the way that specific differences in the linker region correlate with the solution structure of intact antibodies is revealed, thereby visualizing future potential for the rational design of antibodies with designated physicochemical properties and tailored effector functions. In addition, this advanced computational approach is applicable to other flexible multi-domain systems and extends the potential for investigating flexibility in solutions of macromolecules by small-angle X-ray scattering.

Multi-scale Investigation of Heterogeneous Swift Heavy Ion Tracks in Stannate Pyrochlore

2021 ◽  
Author(s):  
Eric O'Quinn ◽  
Cameron Tracy ◽  
William F. Cureton ◽  
Ritesh Sachan ◽  
Joerg C. Neuefeind ◽  
...  
Keyword(s):  
Electron Microscopy ◽  
Transmission Electron Microscopy ◽  
Heavy Ion ◽  
X Ray Diffraction ◽  
X Ray ◽  
Structural Modifications ◽  
Multi Scale ◽  
Ion Tracks ◽  
Swift Heavy Ion ◽  
Transmission Electron

Er2Sn2O7 pyrochlore was irradiated with swift heavy Au ions (2.2 GeV), and the induced structural modifications were systematically examined using complementary characterization techniques including transmission electron microscopy (TEM), X-ray diffraction...

Spacer conformation in biologically active molecules

2004 ◽  
Vol 76 (5) ◽  
pp. 959-964 ◽  
Author(s):  
J. Karolak-Wojciechowska ◽  
A. Fruzinski
Keyword(s):  
Statistical Data ◽  
Population Analysis ◽  
Cambridge Structural Database ◽  
Biologically Active ◽  
Aliphatic Chain ◽  
X Ray ◽  
Flexible Spacer ◽  
Conformational Preferences ◽  
Structural Database ◽  
The One

Based on our contemporary studies on the structures of biologically active molecules, we focus our attention on the aliphatic chain and its conformation. That flexible spacer definitely influenced the balanced position of all pharmacophoric points in molecules of biological ligands. The one atomic linker and two or three atomic spacers with one heteroatom X =O, S, CH2, NH have been taken into account. The conformational preferences clearly depend on the heteroatom X. In the discussion, we utilize our own X-ray data, computation chemistry methods, population analysis, and statistical data from the Cambridge Structural Database (CSD).

In-Situ Diffraction Studies of Gas Storage Materials on a Laboratory X-Ray System

2013 ◽  
Vol 1544 ◽  
Author(s):  
Marco Sommariva ◽  
Harald van Weeren ◽  
Olga Narygina ◽  
Jan-André Gertenbach ◽  
Christian Resch ◽  
...  
Keyword(s):  
Large Scale ◽  
Fossil Fuels ◽  
Reaction Chamber ◽  
Hydrogen Gas ◽  
Gas Pressure ◽  
X Ray Diffraction ◽  
X Ray ◽  
Structural Modifications ◽  
Model Studies

ABSTRACTThe sorption processes for hydrogen and carbon dioxide are of considerable, and growing interest, particularly due to their relevance to a society that seeks to replace fossil fuels with a more sustainable energy source. X-ray diffraction allows a unique perspective for studying structural modifications and reaction mechanisms that occur when gas and solid interact. The fundamental challenge associated with such a study is that experiments are conducted while the solid sample is held under a gas pressure. To date in-situ high gas pressure studies of this nature have typically been undertaken at large-scale facilities such as synchrotrons or on dedicated laboratory instruments. Here we report high-pressure XRD studies carried out on a multi-purpose diffractometer. To demonstrate the suitability of the equipment, two model studies were carried out, firstly the reversible hydrogen cycling over LaNi5, and secondly the structural change that occurs during the decomposition of ammonia borane that results in the generation of hydrogen gas in the reaction chamber. The results have been finally compared to the literature. The study has been made possible by the combination of rapid X-ray detectors with a reaction chamber capable of withstanding gas pressures up to 100 bar and temperatures up to 900 °C.

Oxygen K-shell spectroscopy of isolated progressively solvated peptide

2020 ◽  
Vol 22 (23) ◽  
pp. 12909-12917
Author(s):  
Aleksandar R. Milosavljević ◽  
Kari Jänkälä ◽  
Miloš Lj. Ranković ◽  
Francis Canon ◽  
John Bozek ◽  
...  
Keyword(s):  
Solvation Shell ◽  
Core Excitation ◽  
Peptide Backbone ◽  
X Ray ◽  
Peptide Core

X-ray spectroscopy of an isolated controllably hydrated peptide: core excitation of the first solvation shell enhances peptide backbone fragmentation.

scholarly journals Effect of Polymers (PEG and PVP) on Sol-Gel Synthesis of Microsized Zinc Oxide

2013 ◽  
Vol 2013 ◽  
pp. 1-7 ◽  
Author(s):  
Thilagavathi Thirugnanam
Keyword(s):  
Sol Gel ◽  
Cost Effective ◽  
X Ray Diffraction ◽  
X Ray ◽  
Structural Modifications ◽  
Phase Pure ◽  
Sol Gel Synthesis ◽  
Polyethylene Glycol 6000 ◽  
Granular Morphology ◽  
Scanning Electron

Fibers irregular and seed-like microcrystalline ZnO were synthesized by using a cost-effective and low temperature aqueous sol-gel method. Various polymers, namely, polyethylene glycol 6000 (PEG 6000) and polyvinyl pyrrolidone (PVP), were used as structure directing agents. The samples were characterized by X-ray diffraction (XRD), Fourier transform infrared spectroscopy (FTIR), and scanning electron microscopy (SEM). The X-ray diffraction pattern revealed the formation of phase-pure ZnO micropowders. It is observed that the polymers play an important role in modifying the surface morphology and the size of the crystallites. A compact granular morphology is observed for the ZnO samples without polymer. The samples exhibit microparticles of size 100 nm for PVP and for PEG-mediated growth, whereas microporous corrugated morphology is observed for added PEG-mediated micropowder. FTIR study is used to confirm the structural modifications occurring in the polymers.

scholarly journals Resolving structural modifications of colloidal glasses by combining x-ray scattering and rheology

2013 ◽  
Vol 3 (1) ◽  
Author(s):  
D. Denisov ◽  
M. T. Dang ◽  
B. Struth ◽  
G. Wegdam ◽  
P. Schall
Keyword(s):  
X Ray ◽  
Structural Modifications ◽  
X Ray Scattering ◽  
Colloidal Glasses ◽  
Ray Scattering

Disordered misfit [Ca2CoO3][CoO2]1.62 structure revisited via a new intrinsic modulation

2008 ◽  
Vol 64 (2) ◽  
pp. 144-153 ◽  
Author(s):  
Hervé Muguerra ◽  
Dominique Grebille ◽  
Françoise Bourée
Keyword(s):  
Electronic Structure ◽  
Single Crystal ◽  
Diffraction Experiment ◽  
X Ray Diffraction ◽  
Neutron Diffraction Experiment ◽  
X Ray ◽  
Structural Modifications ◽  
Local Ordering ◽  
Powder Neutron Diffraction ◽  
Modulation Vector

The structure of the thermoelectric lamellar misfit cobalt oxide [Ca2CoO3][CoO2]1.62 was refined again using single-crystal X-ray diffraction data. A new commensurate intrinsic modulation was observed involving a modulation vector orthogonal to the misfit direction (⅔,0,−⅓). The five-dimensional superspace group is C2/m(1δ0)(α0γ)gm and the structure was solved using a commensurate approximation. A new model is given involving an occupation modulation of the split sites of the [CoO] layer. This [CoO] layer can be described by triple chains running along b. The residual disorder along b can then be explained by the assumption of a local ordering with two types of clusters: CoO2 and Co5O4. A powder neutron diffraction experiment confirmed the ordering evidenced by the single-crystal X-ray diffraction study, but was not sufficient by itself to deal with this double modulated scheme. The new intrinsic modulation is destroyed by partial metal substitutions in the [CoO] layer. The structural modifications of this layer directly influence the physical properties which are related to the electronic structure of the [CoO2] layers.

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