scholarly journals Impact of the isomerism of peptide mimetics on the assembly and properties: quick and onsite gas phase detection of acid and alcohols

2022 ◽  
Author(s):  
Deepta Chattapadhyay ◽  
Sujay Nandi ◽  
Debasish Haldar

The effect of isomerism on the structure, self-assembly and properties of two peptide mimetics has been investigated. The peptide mimetics contain m-aminobenzoic acid, p-aminobenzoic acid and N,N'-dicyclohexylurea. From X-ray crystallography,...

2002 ◽  
Vol 30 (4) ◽  
pp. 521-525 ◽  
Author(s):  
O. S. Makin ◽  
L. C. Serpell

The pathogenesis of the group of diseases known collectively as the amyloidoses is characterized by the deposition of insoluble amyloid fibrils. These are straight, unbranching structures about 70–120 å (1 å = 0.1 nm) in diameter and of indeterminate length formed by the self-assembly of a diverse group of normally soluble proteins. Knowledge of the structure of these fibrils is necessary for the understanding of their abnormal assembly and deposition, possibly leading to the rational design of therapeutic agents for their prevention or disaggregation. Structural elucidation is impeded by fibril insolubility and inability to crystallize, thus preventing the use of X-ray crystallography and solution NMR. CD, Fourier-transform infrared spectroscopy and light scattering have been used in the study of the mechanism of fibril formation. This review concentrates on the structural information about the final, mature fibril and in particular the complementary techniques of cryo-electron microscopy, solid-state NMR and X-ray fibre diffraction.


1997 ◽  
Vol 50 (10) ◽  
pp. 977 ◽  
Author(s):  
Daniel E. Lynch ◽  
Graham Smith ◽  
Karl A. Byriel ◽  
Colin H. L. Kennard

A series of molecular adducts of the isomeric aminobenzoic acids with the nitro-substituted Lewis bases 2-chloro-5-nitropyridine, 5-nitroquinoline and 5-nitroisoquinoline has been prepared and characterized by using infrared spectroscopy and X-ray powder diffraction, and in four cases by single-crystal X-ray diffraction methods. These four compounds are the adducts of 3-aminobenzoic acid with 5-nitroquinoline [(C7H7NO2)(C9H6N2O2)], 4-aminobenzoic acid with 5-nitroquinoline [(C7H7NO2)2(C9H6N2O2)], 2-aminobenzoic acid with 5-nitroisoquinoline [(C7H7NO2)(C9H6N2O2)] and 4-aminobenzoic acid with 5-nitroisoquinoline [(C7H7N2O2)(C9H6N2O2)]. Other compounds described are the (1 : 1) adducts of 4-aminobenzoic acid with 2-chloro-5-nitropyridine, and 2-aminobenzoic acid with 5-nitroquinoline. All adducts involve hydrogen-bonding network associations while in none of the examples is any proton transfer involved.


Nanoscale ◽  
2019 ◽  
Vol 11 (47) ◽  
pp. 22880-22889 ◽  
Author(s):  
Howard Z. Ma ◽  
Alasdair I. McKay ◽  
Antonija Mravak ◽  
Michael S. Scholz ◽  
Jonathan M. White ◽  
...  

The structure of a large dicationic silver hydride nanocluster was determined by X-ray crystallography. Pathways to the gas-phase liberation of hydrogen have been identified.


2013 ◽  
Vol 9 ◽  
pp. 2202-2215 ◽  
Author(s):  
Catalin V Maftei ◽  
Elena Fodor ◽  
Peter G Jones ◽  
M Heiko Franz ◽  
Gerhard Kelter ◽  
...  

Taking into consideration the biological activity of the only natural products containing a 1,2,4-oxadiazole ring in their structure (quisqualic acid and phidianidines A and B), the natural product analogs 1-(4-(3-tert-butyl-1,2,4-oxadiazol-5-yl)phenyl)pyrrolidine-2,5-dione (4) and 1-(4-(3-tert-butyl-1,2,4-oxadiazol-5-yl)phenyl)-1H-pyrrole-2,5-dione (7) were synthesized starting from 4-(3-tert-butyl-1,2,4-oxadiazol-5-yl)aniline (1) in two steps by isolating the intermediates 4-(4-(3-tert-butyl-1,2,4-oxadiazol-5-yl)phenylamino)-4-oxobutanoic acid (3) and (Z)-4-(4-(3-tert-butyl-1,2,4-oxadiazol-5-yl)phenylamino)-4-oxobut-2-enoic acid (6). The two natural product analogs 4 and 7 were then tested for antitumor activity toward a panel of 11 cell lines in vitro by using a monolayer cell-survival and proliferation assay. Compound 7 was the most potent and exhibited a mean IC50 value of approximately 9.4 µM. Aniline 1 was synthesized by two routes in one-pot reactions starting from tert-butylamidoxime and 4-aminobenzoic acid or 4-nitrobenzonitrile. The structures of compounds 1, 2, 4, 5 and 6 were confirmed by X-ray crystallography.


2020 ◽  
Vol 19 (3) ◽  
pp. 199-206
Author(s):  
Xin-Jing Liu ◽  
Xiu-Ying Qiao ◽  
Yun-Yin Niu

A novel supramolecular compound {(L1) [CdI4]} (L1 = 1-(3-(((1 s,3R,5S)-1,3,5,7,tetraazaadamantan-1-ium-1-yl)methyl)benzyl)-1,3,5,7,-tetraazaadamantan-1-ium) was synthesized from CdI2 and L1 by self-assembly reaction in solution. Its structure was analyzed by X-ray diffraction, and X-ray crystallography showed that the crystal was mononuclear. The compound was characterized by UV, TG, photocatalysis and adsorption.


Science ◽  
2015 ◽  
Vol 349 (6243) ◽  
pp. 95-98 ◽  
Author(s):  
G. Obal ◽  
F. Trajtenberg ◽  
F. Carrión ◽  
L. Tomé ◽  
N. Larrieux ◽  
...  

Retroviruses depend on self-assembly of their capsid proteins (core particle) to yield infectious mature virions. Despite the essential role of the retroviral core, its high polymorphism has hindered high-resolution structural analyses. Here, we report the x-ray structure of the native capsid (CA) protein from bovine leukemia virus. CA is organized as hexamers that deviate substantially from sixfold symmetry, yet adjust to make two-dimensional pseudohexagonal arrays that mimic mature retroviral cores. Intra- and interhexameric quasi-equivalent contacts are uncovered, with flexible trimeric lateral contacts among hexamers, yet preserving very similar dimeric interfaces making the lattice. The conformation of each capsid subunit in the hexamer is therefore dictated by long-range interactions, revealing how the hexamers can also assemble into closed core particles, a relevant feature of retrovirus biology.


Inorganics ◽  
2019 ◽  
Vol 7 (10) ◽  
pp. 119 ◽  
Author(s):  
Hardin ◽  
Ellington ◽  
Nguyen ◽  
Rheingold ◽  
Tschumper ◽  
...  

Two new aromatic pyrimidine-based derivatives designed specifically for halogen bond directed self-assembly are investigated through a combination of high-resolution Raman spectroscopy, X-ray crystallography, and computational quantum chemistry. The vibrational frequencies of these new molecular building blocks, pyrimidine capped with furan (PrmF) and thiophene (PrmT), are compared to those previously assigned for pyrimidine (Prm). The modifications affect only a select few of the normal modes of Prm, most noticeably its signature ring breathing mode, ν1. Structural analyses afforded by X-ray crystallography, and computed interaction energies from density functional theory computations indicate that, although weak hydrogen bonding (C–H···O or C–H···N interactions) is present in these pyrimidine-based solid-state co-crystals, halogen bonding and π-stacking interactions play more dominant roles in driving their molecular-assembly.


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