Pseudocyclic Form of 4-Hydroxypyrrolidine-2-carboxanilide Podands with Trioxyethylene Chain: Modeling, Conformational Search, and NMR Analysis

Glucosylation of the cis- and trans-isomers of 2-(4-methoxybenzyl)cyclohexan-1-ol (1a/1b, 2a/2b, 1a or 2a) was performed to prepare the corresponding alkyl β-D-glucopyranosides, mainly to get analytical data of pure enantiomers of the glucosides (3a-6b), required for subsequent investigations of related compounds with biological activity. One of the employed modifications of the Koenigs-Knorr synthesis resulted in achieving 85-95% yields of pure β-anomers 3a/3b, 4a/4b, 3a or 4a of protected intermediates, with several promoters and toluene as solvent, yielding finally the deprotected products 5a/5b, 6a/6b, 5a or 6a as pure β-anomers. To obtain enantiomerically pure β-anomers of the target structure (3a, 4a, 5a and 6a) for unambiguous structure assignment, an enzymic reduction of 2-(4-methoxybenzyl)cyclohexan-1-one by Saccharomyces cerevisiae whole cells was performed to get (1S,2S)- and (1S,2R)-enantiomers (1a and 2a) of 2-(4-methoxybenzyl)cyclohexan-1-ol. The opposite enantiomers of alkyl β-D-glucopyranosides (5b and 6b) were obtained by separation of the diastereoisomeric mixtures 5a/5b and 6a/6b by chiral HPLC. All stereoisomers of the products (3a-6b) were subjected to a detailed 1H NMR and 13C NMR analysis.

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High Resolution NMR Analysis of the Composition of Copolymer and Mixture of 6-Nylon and 66-Nylon

The Journal of the Society of Chemical Industry Japan ◽

10.1246/nikkashi1898.70.4_460 ◽

1967 ◽

Vol 70 (4) ◽

pp. 460-465

Author(s):

Mitsuru YAMAZAKI ◽

Tsugio TAKEUCHI

Keyword(s):

High Resolution ◽

Nmr Analysis ◽

High Resolution Nmr

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Analysis of the Structural Mechanism of ATP Inhibition at the AAA1 Subunit of Cytoplasmic Dynein-1 Using a Chemical “Toolkit”

International Journal of Molecular Sciences ◽

10.3390/ijms22147704 ◽

2021 ◽

Vol 22 (14) ◽

pp. 7704

Author(s):

Sayi’Mone Tati ◽

Laleh Alisaraie

Keyword(s):

Binding Affinity ◽

Atp Hydrolysis ◽

Critical Role ◽

Motor Protein ◽

Structural Data ◽

Retrograde Transport ◽

Cytoplasmic Dynein ◽

Motor Domain ◽

Conformational Search ◽

Structural Mechanism

Dynein is a ~1.2 MDa cytoskeletal motor protein that carries organelles via retrograde transport in eukaryotic cells. The motor protein belongs to the ATPase family of proteins associated with diverse cellular activities and plays a critical role in transporting cargoes to the minus end of the microtubules. The motor domain of dynein possesses a hexameric head, where ATP hydrolysis occurs. The presented work analyzes the structure–activity relationship (SAR) of dynapyrazole A and B, as well as ciliobrevin A and D, in their various protonated states and their 46 analogues for their binding in the AAA1 subunit, the leading ATP hydrolytic site of the motor domain. This study exploits in silico methods to look at the analogues’ effects on the functionally essential subsites of the motor domain of dynein 1, since no similar experimental structural data are available. Ciliobrevin and its analogues bind to the ATP motifs of the AAA1, namely, the walker-A (W-A) or P-loop, the walker-B (W-B), and the sensor I and II. Ciliobrevin A shows a better binding affinity than its D analogue. Although the double bond in ciliobrevin A and D was expected to decrease the ligand potency, they show a better affinity to the AAA1 binding site than dynapyrazole A and B, lacking the bond. In addition, protonation of the nitrogen atom in ciliobrevin A and D, as well as dynapyrazole A and B, at the N9 site of ciliobrevin and the N7 of the latter increased their binding affinity. Exploring ciliobrevin A geometrical configuration suggests the E isomer has a superior binding profile over the Z due to binding at the critical ATP motifs. Utilizing the refined structure of the motor domain obtained through protein conformational search in this study exhibits that Arg1852 of the yeast cytoplasmic dynein could involve in the “glutamate switch” mechanism in cytoplasmic dynein 1 in lieu of the conserved Asn in AAA+ protein family.

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Structural Characterization of a Polysaccharide from Gastrodia elata and Its Bioactivity on Gut Microbiota

Molecules ◽

10.3390/molecules26154443 ◽

2021 ◽

Vol 26 (15) ◽

pp. 4443

Author(s):

Jiangyan Huo ◽

Min Lei ◽

Feifei Li ◽

Jinjun Hou ◽

Zijia Zhang ◽

...

Keyword(s):

Molecular Weight ◽

Citric Acid ◽

Gut Microbiota ◽

Structural Characterization ◽

Hot Water ◽

Nmr Analysis ◽

Gastrodia Elata ◽

Hot Water Extraction ◽

Hydroxybenzyl Alcohol

A novel homogeneous polysaccharide named GEP-1 was isolated and purified from Gastrodia elata (G. elata) by hot-water extraction, ethanol precipitation, and membrane separator. GEP-1, which has a molecular weight of 20.1 kDa, contains a polysaccharide framework comprised of only glucose. Methylation and NMR analysis showed that GEP-1 contained 1,3,6-linked-α-Glcp, 1,4-linked-α-Glcp, 1,4-linked-β-Glcp and 1,4,6-linked-α-Glcp. Interestingly, GEP-1 contained citric acid and repeating p-hydroxybenzyl alcohol as one branch. Furthermore, a bioactivity test showed that GEP-1 could significantly promote the growth of Akkermansia muciniphila (A. muciniphila) and Lacticaseibacillus paracasei (L.paracasei) strains. These results implied that GEP-1 might be useful for human by modulating gut microbiota.

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Mono- and Dinitro-BN-Naphthalenes: Formation and Characterization

Molecules ◽

10.3390/molecules26144209 ◽

2021 ◽

Vol 26 (14) ◽

pp. 4209

Author(s):

Mao-Xi Zhang ◽

Nathaniel B. Zuckerman ◽

Philip F. Pagoria ◽

Bradley A. Steele ◽

I-Feng Kuo ◽

...

Keyword(s):

Electron Density ◽

Nmr Analysis ◽

X Ray ◽

Boron Nitrogen

Mono- and dinitro-BN-naphthalenes, i.e., 1-nitro-, 3-nitro-, 1,6-dinitro-, 3,6-dinitro-, and 1,8-dinitro-BNN, were generated in the nitration of 9,10-BN-naphthalene (BNN), a boron–nitrogen (BN) bond-embedded naphthalene, with AcONO2 and NO2BF4 in acetonitrile. The nitrated products were isolated and characterized by NMR, GC-MS, IR, and X-ray single crystallography. The effects of the nitration on the electron density and aromaticity of BNN were evaluated by B-11 NMR analysis and HOMA calculations.

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