Designer cyclopeptides for self-assembled tubular structures

2000 ◽  
Vol 72 (3) ◽  
pp. 365-372 ◽  
Author(s):  
Darshan Ranganathan ◽  
C. Lakshmi ◽  
V. Haridas ◽  
M. Gopikumar
Keyword(s):  
Design Strategy ◽  
Single Step ◽  
Simple Design ◽  
Tubular Structures ◽  
Peptide Nanotubes ◽  
X Ray ◽  
X Ray Crystallography ◽  
Self Assembling ◽  
Direct Condensation ◽  
Hydrogen Bonded

A simple design strategy for a facile and direct entry into hydrogen-bonded peptide nanotubes is delineated with polymethylene-bridged cystine-based macrocycles. The key feature of the design is the placement of a pair of self-complementary hydrogen-bonding (NH–CO or NH–CO–NH) groups at almost opposite poles of the ring. A large variety of cyclobisamides and bisureas prepared in a single step by direct condensation of commercially available 1,ω-alkane dicarbonyl dichloride or diisocyanate with either cystine diOMe or its extended bispeptide were examined by X-ray crystallography and shown to possess an inherent property of self-assembling into hydrogen-bonded, open-ended, hollow tubular structures. The totally hydrophobic interior of the cyclobisamide tubes creates a micro environment capable of solubilizing highly lipophilic substances in water. The cyclic bisurea tubes are demonstrated to act as excellent receptors for selective binding to 1,ω-alkane dicarboxylates. The scope of the design is extended to the creation of tubular structures by stacking of rings through aromatic π-π interactions.

Novel peroxosolvates of tetraalkylammonium halides: the first case of layers containing hydrogen-bonded peroxide molecules

CrystEngComm ◽  
2021 ◽  
Author(s):  
Mger A. Navasardyan ◽  
Stanislav Bezzubov ◽  
Alexander G. Medvedev ◽  
Petr V Prikhodchenko ◽  
Churakov Andrei
Keyword(s):  
Hydrogen Peroxide ◽  
X Ray ◽  
X Ray Crystallography ◽  
First Case ◽  
Tetraalkylammonium Halides ◽  
Hydrogen Bonded

Novel peroxosolvates of tetraalkylammonium halides Et4N+Cl–•2(H2O2) (1), Et4N+Br–•2(H2O2) (2), Me3(ClCH2CH2)N+Cl–•H2O2 (3) and Me3PhN+Cl–•H2O2 (4) were prepared from concentrated hydrogen peroxide and the corresponding structures were determined by X-ray crystallography. Structures...

scholarly journals Molecular Recognition in Proton-Transfer Compounds of Brucine with Achiral Substituted Salicylic Acid Analogues

2006 ◽  
Vol 59 (5) ◽  
pp. 320 ◽  
Author(s):  
Graham Smith ◽  
Urs D. Wermuth ◽  
Peter C. Healy ◽  
Jonathan M. White
Keyword(s):  
Proton Transfer ◽  
Three Dimensional ◽  
Water Molecules ◽  
Sulfosalicylic Acid ◽  
X Ray ◽  
X Ray Crystallography ◽  
Guest Species ◽  
Substituted Benzoic Acids ◽  
Proton Transfer Compounds ◽  
Hydrogen Bonded

The 1:1 proton-transfer brucinium compounds from the reaction of the alkaloid brucine with 5-nitrosalicylic acid, 3,5-dinitrosalicylic acid, and 5-sulfosalicylic acid, namely anhydrous brucinium 5-nitrosalicylate (1), brucinium 3,5-dinitrosalicylate monohydrate (2), and brucinium 5-sulfosalicylate trihydrate (3) have been prepared and their crystal structures determined by X-ray crystallography. All structures further demonstrate the selectivity of brucine for meta-substituted benzoic acids and comprise three-dimensional hydrogen-bonded framework polymers. Two of the compounds (1 and 3) have the previously described undulating brucine sheet host-substructures which incorporate interstitially hydrogen-bonded salicylate anion guest species and additionally in 3 the water molecules of solvation. The structure of 2 differs in having a three-centre brucinium–salicylate anion bidentate N+–H···O(carboxyl) hydrogen-bonding association linking the species through interstitial associations involving also the water molecules of solvation. A review of the crystallographic structural literature on strychnine and brucine is also given.

Molecular tectonics — Use of urethanes and ureas derived from tetraphenylmethane and tetraphenylsilane to build porous chiral hydrogen-bonded networks

2004 ◽  
Vol 82 (2) ◽  
pp. 386-398 ◽  
Author(s):  
Dominic Laliberté ◽  
Thierry Maris ◽  
James D Wuest
Keyword(s):  
Hydrogen Bonding ◽  
Asymmetric Catalysis ◽  
Crystal Engineering ◽  
Three Dimensional ◽  
Enantiomerically Pure ◽  
X Ray ◽  
Molecular Tectonics ◽  
X Ray Crystallography ◽  
Open Networks ◽  
Hydrogen Bonded

Tetraphenylmethane, tetraphenylsilane, and simple derivatives with substituents that do not engage in hydrogen bonding typically crystallize as close-packed structures with essentially no space available for the inclusion of guests. In contrast, derivatives with hydrogen-bonding groups are known to favor the formation of open networks that include significant amounts of guests. To explore this phenomenon, we synthesized six new derivatives 5a–5e and 6a of tetraphenylmethane and tetraphenylsilane with urethane and urea groups at the para positions, crystallized the compounds, and determined their structures by X-ray crystallography. As expected, all six compounds crystallize to form porous three-dimensional hydrogen-bonded networks. In the case of tetraurea 5e, 66% of the volume of the crystals is accessible to guests, and guests can be exchanged in single crystals without loss of crystallinity. Of special note are: (i) the use of tetrakis(4-isocyanatophenyl)methane (1f) as a precursor for making enantiomerically pure tetraurethanes and tetraureas, including compounds 5b, 5c; and (ii) their subsequent crystallization to give porous chiral hydrogen-bonded networks. Such materials promise to include chiral guests enantioselectively and to be useful in the separation of racemates, asymmetric catalysis, and other applications.Key words: crystal engineering, molecular tectonics, hydrogen bonding, networks, porosity, urethanes, ureas, tetraphenylmethane, tetraphenylsilane.

scholarly journals The S-Layer Glycome—Adding to the Sugar Coat of Bacteria

2011 ◽  
Vol 2011 ◽  
pp. 1-16 ◽  
Author(s):  
Robin Ristl ◽  
Kerstin Steiner ◽  
Kristof Zarschler ◽  
Sonja Zayni ◽  
Paul Messner ◽  
...  
Keyword(s):  
Unique Feature ◽  
Nanometer Scale ◽  
Capsular Polysaccharides ◽  
Glycosidic Linkage ◽  
Cell Surfaces ◽  
X Ray ◽  
Tyrosine Residues ◽  
X Ray Crystallography ◽  
Gram Positive Bacteria ◽  
Self Assembling

The amazing repertoire of glycoconjugates present on bacterial cell surfaces includes lipopolysaccharides, capsular polysaccharides, lipooligosaccharides, exopolysaccharides, and glycoproteins. While the former are constituents of Gram-negative cells, we review here the cell surface S-layer glycoproteins of Gram-positive bacteria. S-layer glycoproteins have the unique feature of self-assembling into 2D lattices providing a display matrix for glycans with periodicity at the nanometer scale. Typically, bacterial S-layer glycans are O-glycosidically linked to serine, threonine, or tyrosine residues, and they rely on a much wider variety of constituents, glycosidic linkage types, and structures than their eukaryotic counterparts. As the S-layer glycome of several bacteria is unravelling, a picture of how S-layer glycoproteins are biosynthesized is evolving. X-ray crystallography experiments allowed first insights into the catalysis mechanism of selected enzymes. In the future, it will be exciting to fully exploit the S-layer glycome for glycoengineering purposes and to link it to the bacterial interactome.

scholarly journals Polymorphic G:G mismatches act as hotspots for inducing right-handed Z DNA by DNA intercalation

2019 ◽  
Vol 47 (16) ◽  
pp. 8899-8912 ◽  
Author(s):  
Roshan Satange ◽  
Chien-Ying Chuang ◽  
Stephen Neidle ◽  
Ming-Hon Hou
Keyword(s):  
Actinomycin D ◽  
Single Step ◽  
Dna Intercalation ◽  
Chromomycin A3 ◽  
Dna Structures ◽  
X Ray ◽  
X Ray Crystallography ◽  
Dna Mismatches ◽  
Z Dna ◽  
First Time

Abstract DNA mismatches are highly polymorphic and dynamic in nature, albeit poorly characterized structurally. We utilized the antitumour antibiotic CoII(Chro)2 (Chro = chromomycin A3) to stabilize the palindromic duplex d(TTGGCGAA) DNA with two G:G mismatches, allowing X-ray crystallography-based monitoring of mismatch polymorphism. For the first time, the unusual geometry of several G:G mismatches including syn–syn, water mediated anti–syn and syn–syn-like conformations can be simultaneously observed in the crystal structure. The G:G mismatch sites of the d(TTGGCGAA) duplex can also act as a hotspot for the formation of alternative DNA structures with a GC/GA-5′ intercalation site for binding by the GC-selective intercalator actinomycin D (ActiD). Direct intercalation of two ActiD molecules to G:G mismatch sites causes DNA rearrangements, resulting in backbone distortion to form right-handed Z-DNA structures with a single-step sharp kink. Our study provides insights on intercalators-mismatch DNA interactions and a rationale for mismatch interrogation and detection via DNA intercalation.

Preparation of Rhenium Diamino Dithiolate Complexes. The X-Ray Crystal Structure of Oxo(1,1,8,8-tetraethyl-3,6-diazaoctane-1,8-dithiolato)rhenium

1993 ◽  
Vol 46 (7) ◽  
pp. 1093 ◽  
Author(s):  
TW Jackson ◽  
M Kojima ◽  
RM Lambrecht
Keyword(s):  
Crystal Structure ◽  
Hydrogen Bonding ◽  
Intermolecular Hydrogen Bonding ◽  
X Ray ◽  
X Ray Crystallography ◽  
Dithiolate Complexes ◽  
Hydrogen Bonded

The complexes oxo (1,1,8,8-tetraethyl-3,6-diazaoctane-1,8-dithiolato)rhenium[ ReO ( tedadt )], oxo (1,1,8,8-tetraethyl-4,4-dimethyl-3,6-diazaoctane-1,8-dithiolato)rhenium [ ReO ( tedmdadt )] and (1,1,4,4,8,8-hexamethyl-3,6-diazaoctane-1,8-dithiolato) oxorhenium [ ReO ( hmdadt )] were prepared. The crystal structure of the complex ReO ( tedadt ) was determined by X-ray crystallography to be a hydrogen-bonded dimer . This is the first example of intermolecular hydrogen bonding in rhenium diamino dithiolate ( dadt ) complexes.

Notizen: Preparation and Crystal Structure of the Hydrogen-Bonded Cyclic Dimer of PhP(S)[N(CH2Ph)2]OH, HN(CH2Ph)2+

1976 ◽  
Vol 31 (10) ◽  
pp. 1421-1422 ◽  
Author(s):  
T. Stanley Cameron ◽  
James D. Healy ◽  
Robert A. Shaw ◽  
Michael Woods
Keyword(s):  
Crystal Structure ◽  
Title Compound ◽  
Cyclic Dimer ◽  
X Ray ◽  
X Ray Crystallography ◽  
Hydrogen Bonded

The structure of the title compound was determined by X-ray crystallography. The compound is a cyclic dimer with short N···O and N···S contacts.

A novel tubular hydrogen-bond pattern in a new diazaphosphole oxide: a combination of X-ray crystallography and theoretical study of hydrogen bonds

2017 ◽  
Vol 73 (7) ◽  
pp. 508-516 ◽  
Author(s):  
Fahimeh Sabbaghi ◽  
Mehrdad Pourayoubi ◽  
Abolghasem Farhadipour ◽  
Nazila Ghorbanian ◽  
Pavel V. Andreev
Keyword(s):  
Hydrogen Bond ◽  
Hydrogen Bonds ◽  
Coupling Constant ◽  
X Ray ◽  
X Ray Crystallography ◽  
H Nmr ◽  
Hydrogen Bond Pattern ◽  
Orbital Analysis ◽  
Tubular Array ◽  
Hydrogen Bonded

In the structure of 2-(4-chloroanilino)-1,3,2λ4-diazaphosphol-2-one, C12H11ClN3OP, each molecule is connected with four neighbouring molecules through (N—H)2...O hydrogen bonds. These hydrogen bonds form a tubular arrangement along the [001] direction built from R 3 3(12) and R 4 3(14) hydrogen-bond ring motifs, combined with a C(4) chain motif. The hole constructed in the tubular architecture includes a 12-atom arrangement (three P, three N, three O and three H atoms) belonging to three adjacent molecules hydrogen bonded to each other. One of the N—H groups of the diazaphosphole ring, not co-operating in classical hydrogen bonding, takes part in an N—H...π interaction. This interaction occurs within the tubular array and does not change the dimension of the hydrogen-bond pattern. The energies of the N—H...O and N—H...π hydrogen bonds were studied by NBO (natural bond orbital) analysis, using the experimental hydrogen-bonded cluster of molecules as the input file for the chemical calculations. In the 1H NMR experiment, the nitrogen-bound proton of the diazaphosphole ring has a high value of 17.2 Hz for the 2 J H–P coupling constant.

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