<i>cyclo</i>-Bis(paraquat-<i>m</i>-terphenylene) tetrakis(hexafluorophosphate) tetrahydrate

Ravishankar, T.; Chinnakali, K.; Srinivasan, Kannupal; Rajakumar, Perumal; Usman, Anwar; Fun, Hoong‐Kun

doi:10.1107/s1600536802020068

Cited by 2 publications

(5 citation statements)

References 8 publications

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“…The direct and water-mediated proteinligand interactions in the different crystallographic structures are summarized in Tables 2 and 3. Taken all together, our results show that, in all complexes, the -galactoside residues present a highly conserved conformation in the ligand binding pocket, and thus, the lectinglycan interactions are in accordance with those previously reported (Banerjee et al, 1996;Ravishankar et al, 1997Ravishankar et al, , 1999Ravishankar et al, , 2001Kundhavai Natchiar et al, 2004, 2006Goel et al, 2005). Thus, as expected, the β-galactoside moieties present in the synthetic N-and Slinked glycoclusters represent the main recognition elements for lectin binding.…”

Section: Binding Of the Galactose Moiety In The Different Synthetic Gsupporting

confidence: 92%

“…The protein-galactose atomic interactions are nearly identical to those observed in the PNA--galactosides complexes previously reported ( Fig. 4) (Banerjee et al, 1994(Banerjee et al, , 1996Ravishankar et al, 1997Ravishankar et al, , 1999Ravishankar et al, , 2001Kundhavai Natchiar et al, 2006). Briefly, O2gal interacts with two ordered water molecules, W1 and W2 (the latter was not observed in the PNA-STG complex).…”

Section: Binding Of the Galactose Moiety In The Different Synthetic Gsupporting

confidence: 83%

“…Each subunit of PNA complexed with the glycoclusters present the characteristic jelly-roll lectin fold, which consists of a nearly flat six-stranded β-sheet, a curved seven-stranded βsheet, a small five-stranded β-sheet (linking the two larger β-sheets), and a number of loops of differing lengths and conformations, as reported (Banerjee et al, 1994(Banerjee et al, , 1996Ravishankar et al, 1999). The quaternary arrangement is mainly stabilized by contacts between the flat six-stranded β-sheets from chains A-D and chains B-C.…”

Section: Overall Structural Featuresmentioning

confidence: 60%

“…PNA has been widely used as a model lectin to structurally characterize the effects of a variety of β-galactoside and β-lactoside ligands (Banerjee et al, 1994;Ravishankar et al, 1997Ravishankar et al, , 1999Ravishankar et al, , 2001Kundhavai Natchiar et al, 2004, 2006Goel et al, 2005). However, most of the PNA ligands reported to date correspond to O-linked carbohydrates, which are expected to have limited half-life in biological media since they are sensitive to glycosidasemediated hydrolysis.…”

Section: Introductionmentioning

confidence: 99%

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Crystal structures of peanut lectin in the presence of synthetic β-N- and β-S-galactosides disclose evidences for the recognition of different glycomimetic ligands

Cagnoni

Primo

Klinke

et al. 2020

Preprint

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ORCID:https://orcid.org/0000-0002-5448-5483. # equally contributed to this work Keywords Carbohydrate−protein interactions, peanut agglutinin, glycoclusters, multivalent ligands, lectin structure, X-ray crystallography, isothermal titration calorimetry, molecular dynamics. AbstractCarbohydrate−lectin interactions are involved in important cellular recognition processes, including viral and bacterial infections, inflammation, and tumor metastasis. Hence, the structural studies of lectin-synthetic glycan complexes are essential for understanding the lectin recognition processes and the further design of promising chemotherapeutics that interfere with sugar-lectin interactions.Plant lectins are excellent models for the study of the molecular recognition process. Among them, peanut lectin (PNA) is highly relevant in the glycobiology field, because of its specificity for β-galactosides, showing high affinity towards the Thomsen-Friedenreich (TF) antigen, a well-known tumor-associated carbohydrate antigen. Given this specificity, PNA is one of the most frequently used molecular probes for the recognition of tumor cell-surface O-glycans. Thus, it has been extensively used in glycobiology for inhibition studies with a variety of βgalactoside and β-lactoside ligands. Herein, crystal structures of PNA are reported in complex with six novel synthetic hydrolytically stable β-N-and β-S-galactosides. These complexes, along with computational simulations, disclosed key molecular binding interactions of the different sugars to PNA at the atomic level, revealing the role of specific water molecules in the protein-ligand recognition. Furthermore, binding affinity studies measured by isothermal titration calorimetry showed dissociation constant values in the micromolar range, as well as a positive glycoside cluster effect in terms of affinity in the case of the divalent compounds. Taken together, this work provides qualitative structural rationale for the upcoming synthesis of optimized glycoclusters, designed for the study of lectinmediated biological processes. The understanding of the recognition of β-N-and β-Sgalactosides with PNA represents a benchmark in protein-carbohydrate interactions since they are novel synthetic ligands not belonging to the family of O-linked glycosides.

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Section: Binding Of the Galactose Moiety In The Different Synthetic Gsupporting

confidence: 92%

Section: Binding Of the Galactose Moiety In The Different Synthetic Gsupporting

confidence: 83%

Section: Overall Structural Featuresmentioning

confidence: 60%

Section: Introductionmentioning

confidence: 99%

See 2 more Smart Citations

Crystal structures of peanut lectin in the presence of synthetic β-N- and β-S-galactosides disclose evidences for the recognition of different glycomimetic ligands

Cagnoni

Primo

Klinke

et al. 2020

Preprint

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“…[8] The ORTEP plot of the crystal structure of 3a is shown in Figure 1. The centrosymmetric macrocyclic tetracation as a whole assumes a chair-like conformation.…”

Section: Cyclophanes With M-terphenyl Spacersmentioning

confidence: 99%

Novel 4,4′‐Bipyridinium‐Based Cationic Mono‐ and Bicyclic Cyclophanes

Rajakumar

Srinivasan

2003

Eur J Org Chem

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The intra-annularly functionalised tetracationic cyclophanes 3a−b were synthesised from the corresponding m-terphenyl dibromides and 4,4Ј-bipyridine by a simple quaternisation methodology. An intra-annularly linked tetracationic cyclophane 10 was synthesised in three steps and it possesses a concave structure and novel intramolecular CT interactions. Synthesis of the tetracationic cyclophanes 13, 16a and 16b containing carbonyl groups was accomplished from the corresponding carbonyl dibromides and 4,4Ј-bipyridine. Sixfold coupling of a tricarbonyl tribromide with 4,4Ј-bipyridine af-

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cyclo-Bis(paraquat-m-terphenylene) tetrakis(hexafluorophosphate) tetrahydrate

Abstract: Key indicatorsSingle-crystal X-ray study T = 183 K Mean '(C±C) = 0.004 A Ê R factor = 0.062 wR factor = 0.149 Data-to-parameter ratio = 17.0 For details of how these key indicators were automatically derived from the article, see

Cited by 2 publications

References 8 publications

Crystal structures of peanut lectin in the presence of synthetic β-N- and β-S-galactosides disclose evidences for the recognition of different glycomimetic ligands

Crystal structures of peanut lectin in the presence of synthetic β-N- and β-S-galactosides disclose evidences for the recognition of different glycomimetic ligands

Novel 4,4′‐Bipyridinium‐Based Cationic Mono‐ and Bicyclic Cyclophanes

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