scholarly journals Intermolecular Chirality Modulation of Binaphthalene-Bridged Bisporphyrins With Chiral Diamines

2021 ◽  
Vol 8 ◽  
Author(s):  
Wenxin Lu ◽  
Lei Gong ◽  
Chaorui Su ◽  
Qibao Wang ◽  
Qing Ling ◽  
...  
Keyword(s):  
Molecular Modeling ◽  
Optical Sensing ◽  
Supramolecular Interactions ◽  
Chiral Diamine ◽  
Sandwich Type ◽  
Chiral Diamines ◽  
Circular Dichroïsm ◽  
Porphyrin Dimers ◽  
Nmr Titrations

A new pair of 2,2ʹ-diamino-1,1ʹ-binaphthyl linked porphyrin dimers, (R)-/(S)-H, were synthesized to study their supramolecular interactions with a pair of chiral diamines ((R)-/(S)-PPDA) by using UV-Vis absorption, fluorescence and NMR titrations. The spectroscopic titrations indicated that sandwich-type 1:1 complexes were formed at low guest concentration and then transformed to 1:2 open complexes at high guest concentration. The supramolecular interactions afforded sensitive circular dichroism responses, and the CD signs of the 1:1 complexes are decided by the stereostructure of chiral diamine guests. Moreover, due to the shortened linking units, (R)-/(S)-H show more sensitive and predicable CD response than the previously reported hosts (R)-/(S)-H1 and this can be reasonably explained by DFT molecular modeling. The present results suggest (R)-/(S)-H are promising for chiral optical sensing.

Supramolecular Interactions in Aromatic Structures for Non-Optical and Optical Chemosensors of Explosive Chemicals

2021 ◽  
Vol 317 ◽  
pp. 202-207
Author(s):  
Juan Matmin ◽  
Nur Fatiha Ghazalli ◽  
Fazira Ilyana Abdul Razak ◽  
Hendrik O. Lintang ◽  
Mohamad Azani Jalani
Keyword(s):  
Hydrogen Bonding ◽  
High Performance ◽  
Molecular Design ◽  
Optical Sensing ◽  
Green Emission ◽  
Supramolecular Interactions ◽  
Side Chain ◽  
Optical Chemosensors ◽  
Random Aggregate ◽  
Metal Metal

The scientific investigation based on the molecular design of aromatic compounds for high-performance chemosensor is challenging. This is because their multiplex interactions at the molecular level should be precisely determined before the desired compounds can be successfully used as sensing materials. Herein, we report on the molecular design of chemosensors based on aromatic structures of benzene as the organic motif of benzene-1,3,5-tricarboxamides (BTA), as well as the benzene pyrazole complexes (BPz) side chain, respectively. In the case of BTA, the aromatic benzene acts as the centre to allow the formation of π–π stacking for one-dimensional materials having rod-like arrangements that are stabilized by threefold hydrogen bonding. We found that when nitrate was applied, the rod-like BTA spontaneously formed into a random aggregate due to the deformation of its hydrogen bonding to form inactive nitroso groups for non-optical sensing capability. For the optical chemosensor, the aromatic benzene is decorated as a side-chain of BPz to ensure that cage-shaped molecules make maximum use of their centre providing metal-metal interactions for fluorescence-based sensing materials. In particular, when exposed to benzene, Cu-BPz displayed a blue-shift of its original emission band from 616 to 572 nm (Δ = 44 nm) and emitted bright orange to green emission colours. We also observe a different mode of fluorescence-based sensing materials for Au-BPz, which shows a particular quenching mechanism resulting in 81% loss of its original intensity on benzene exposure to give less red-orange emission (λ = 612 nm). The BTA and BPz synthesized are promising high-performance supramolecular chemosensors based on the non-optical and optical sensing capability of a particular interest analyte.

Conformational Analysis and Binding Affinity Determination for Host—Guest Complexation of Alkali Metal Ions with Bis-Crown Ethers by Electrospray Mass Spectrometry and Molecular Modeling

2002 ◽  
Vol 8 (5) ◽  
pp. 375-380 ◽  
Author(s):  
Hui-Fen Wu ◽  
Shun-Min Huan ◽  
Chun-Fu Wu
Keyword(s):  
Mass Spectrometry ◽  
Alkali Metal ◽  
Metal Ions ◽  
Binding Affinity ◽  
Alkali Metal Ions ◽  
Ionization Mass ◽  
Potassium Ions ◽  
Esi Ms ◽  
Sandwich Type

This study presents the application of electrospray ionization mass spectrometry (ESI/MS) to investigate the host–guest complexation phenomenon for an array of alkali metal ions with bis[(benzo-15–crown-5)-15–ylmethyl] pimelate (BBCP). The results have shown that potassium ions possess the best binding affinity with the BBCP, owing to formation of the very stable sandwich-type (1:1) complexes and the strong K+ cation-π electron interactions between the K+ ion and the benzene rings of BBCP. The results of the competition experiments indicate the selectivity for BBCP toward the alkali metal ions is K+ > Rb+ > Cs+ > Na+ > Li+. In addition, combining the results of ESI/MS and molecular mechanics conformational searches reveal that the formation of sandwich-type (1:1) complexes can be observed for larger metal ions including K+, Rb+ and Cs+. As for Na+ ions, both 1:1 and 1:2 complexes can be observed.

scholarly journals Mapping of Epitopes for Autoantibodies to the Type 1 Diabetes Autoantigen IA-2 by Peptide Phage Display and Molecular Modeling: Overlap of Antibody and T Cell Determinants

2004 ◽  
Vol 172 (7) ◽  
pp. 4084-4090 ◽  
Author(s):  
James A. Dromey ◽  
Sarah M. Weenink ◽  
Günther H. Peters ◽  
Josef Endl ◽  
Patrick J. Tighe ◽  
...  
Keyword(s):  
Type 1 Diabetes ◽  
T Cell ◽  
Molecular Modeling ◽  
Phage Display ◽  
Peptide Phage Display

scholarly journals Exploring the binding properties and structural stability of an opsin in the chytrid Spizellomyces punctatus using comparative and molecular modeling

2017 ◽  
Author(s):  
Steven R Ahrendt ◽  
Edgar Mauricio Medina ◽  
Chia-en A Chang ◽  
Jason E Stajich
Keyword(s):  
Molecular Modeling ◽  
Structural Characteristics ◽  
Sequence Similarity ◽  
Ligand Docking ◽  
Binding Properties ◽  
Function Relationship ◽  
Relationship Of ◽  
Future Work

Background. Opsin proteins are seven transmembrane receptor proteins which detect light. Opsins can be classified into two types and share little sequence identity: type 1, typically found in bacteria, and type 2, primarily characterized in metazoa. The type 2 opsins (Rhodopsins) are a subfamily of G-protein coupled receptors (GPCRs), a large and diverse class of seven transmembrane proteins and are generally restricted to metazoan lineages. Fungi use light receptors including opsins to sense the environment and transduce signals for developmental or metabolic changes. Opsins characterized in the Dikarya (Ascomycetes and Basidiomycetes) are of the type 1 bacteriorhodopsin family but the early diverging fungal lineages have not been as well surveyed. We identified by sequence similarity a rhodopsin-like GPCR in genomes of early diverging chytrids and examined the structural characteristics of this protein to assess its likelihood to be homologous to animal rhodopsins and bind similar chromophores. Methods. We used template-based structure modeling, automated ligand docking, and molecular modeling to assess the structural and binding properties of an identified opsin-like protein found in Spizellomyces punctatus, a unicellular, flagellated species belonging to Chytridiomycota, one of the earliest diverging fungal lineages. We tested if sequence and inferred structure were consistent with a solved crystal structure of a type 2 rhodopsin from the squid Todarodes pacificus. Results. Our results indicate that the Spizellomyces opsin has structural characteristics consistent with functional animal type 2 rhodopsins and is capable of maintaining a stable structure when associated with the retinaldehyde chromophore, specifically the 9-cis­-retinal isomer. Together, these results support further the homology of Spizellomyces opsins to animal type 2 rhodopsins. Discussion. This represents the first test of structure/function relationship of a type 2 rhodopsin identified in early branching fungal lineages, and provides a foundation for future work exploring pathways and components of photoreception in early fungi.

scholarly journals Exploring the binding properties and structural stability of an opsin in the chytridSpizellomyces punctatususing comparative and molecular modeling

PeerJ ◽  
2017 ◽  
Vol 5 ◽  
pp. e3206 ◽  
Author(s):  
Steven R. Ahrendt ◽  
Edgar Mauricio Medina ◽  
Chia-en A. Chang ◽  
Jason E. Stajich
Keyword(s):  
Molecular Modeling ◽  
Structural Characteristics ◽  
Sequence Similarity ◽  
Ligand Docking ◽  
Binding Properties ◽  
Function Relationship ◽  
Relationship Of ◽  
Future Work

BackgroundOpsin proteins are seven transmembrane receptor proteins which detect light. Opsins can be classified into two types and share little sequence identity: type 1, typically found in bacteria, and type 2, primarily characterized in metazoa. The type 2 opsins (Rhodopsins) are a subfamily of G-protein coupled receptors (GPCRs), a large and diverse class of seven transmembrane proteins and are generally restricted to metazoan lineages. Fungi use light receptors including opsins to sense the environment and transduce signals for developmental or metabolic changes. Opsins characterized in the Dikarya (Ascomycetes and Basidiomycetes) are of the type 1 bacteriorhodopsin family but the early diverging fungal lineages have not been as well surveyed. We identified by sequence similarity a rhodopsin-like GPCR in genomes of early diverging chytrids and examined the structural characteristics of this protein to assess its likelihood to be homologous to animal rhodopsins and bind similar chromophores.MethodsWe used template-based structure modeling, automated ligand docking, and molecular modeling to assess the structural and binding properties of an identified opsin-like protein found inSpizellomyces punctatus, a unicellular, flagellated species belonging to Chytridiomycota, one of the earliest diverging fungal lineages. We tested if the sequence and inferred structure were consistent with a solved crystal structure of a type 2 rhodopsin from the squidTodarodes pacificus.ResultsOur results indicate that theSpizellomycesopsin has structural characteristics consistent with functional animal type 2 rhodopsins and is capable of maintaining a stable structure when associated with the retinaldehyde chromophore, specifically the 9-cis-retinal isomer. Together, these results support further the homology ofSpizellomycesopsins to animal type 2 rhodopsins.DiscussionThis represents the first test of structure/function relationship of a type 2 rhodopsin identified in early branching fungal lineages, and provides a foundation for future work exploring pathways and components of photoreception in early fungi.

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