scholarly journals Glycoblocks: a schematic three-dimensional representation for glycans and their interactions

2016 ◽  
Vol 73 (2) ◽  
pp. 187-194 ◽  
Author(s):  
Stuart McNicholas ◽  
Jon Agirre

The close-range interactions provided by covalently linked glycans are essential for the correct folding of glycoproteins and also play a pivotal role in recognition processes. Being able to visualise protein–glycan and glycan–glycan contacts in a clear way is thus of great importance for the understanding of these biological processes. In structural terms, glycosylation sugars glue the protein together via hydrogen bonds, whereas non-covalently bound glycans frequently harness additional stacking interactions. Finding an unobscured molecular view of these multipartite scenarios is usually far from trivial; in addition to the need to show the interacting protein residues, glycans may contain many branched sugars, each composed of more than ten non-H atoms and offering more than three potential bonding partners. With structural glycoscience finally gaining popularity and steadily increasing the deposition rate of three-dimensional structures of glycoproteins, the need for a clear way of depicting these interactions is more pressing than ever. Here a schematic representation, named Glycoblocks, is introduced which combines a simplified bonding-network depiction (covering hydrogen bonds and stacking interactions) with the familiar two-dimensional glycan notation used by the glycobiology community, brought into three dimensions by the CCP4 molecular graphics project (CCP4mg).

2006 ◽  
Vol 62 (4) ◽  
pp. 651-665 ◽  
Author(s):  
Silvia Cuffini ◽  
Christopher Glidewell ◽  
John N. Low ◽  
Aline G. de Oliveira ◽  
Marcus V. N. de Souza ◽  
...  

Structures are reported here for eight further substituted N-aryl-2-chloronicotinamides, 2-ClC5H3NCONHC6H4 X-4′. When X = H, compound (I) (C12H9ClN2O), the molecules are linked into sheets by N—H...N, C—H...π(pyridyl) and C—H...π(arene) hydrogen bonds. For X = CH3, compound (II) (C13H11ClN2O, triclinic P\bar 1 with Z′ = 2), the molecules are linked into sheets by N—H...O, C—H...O and C—H...π(arene) hydrogen bonds. Compound (III), where X = F, crystallizes as a monohydrate (C12H8ClFN2O·H2O) and sheets are formed by N—H...O, O—H...O and O—H...N hydrogen bonds and aromatic π...π stacking interactions. Crystals of compound (IV), where X = Cl (C12H8Cl2N2O, monoclinic P21 with Z′ = 4) exhibit inversion twinning: the molecules are linked by N—H...O hydrogen bonds into four independent chains, linked in pairs by C—H...π(arene) hydrogen bonds. When X = Br, compound (V) (C12H8BrClN2O), the molecules are linked into sheets by N—H...O and C—H...N hydrogen bonds, while in compound (VI), where X = I (C12H8ClIN2O), the molecules are linked into a three-dimensional framework by N—H...O and C—H...π(arene) hydrogen bonds and an iodo...N(pyridyl) interaction. For X = CH3O, compound (VII) (C13H11ClN2O2), the molecules are linked into chains by a single N—H...O hydrogen bond. Compound (VIII) (C13H8ClN3O, triclinic P\bar 1 with Z′ = 2), where X = CN, forms a complex three-dimensional framework by N—H...N, C—H...N and C—H...O hydrogen bonds and two independent aromatic π...π stacking interactions.


2014 ◽  
Vol 70 (10) ◽  
pp. o1130-o1130 ◽  
Author(s):  
Wataru Furukawa ◽  
Munenori Takehara ◽  
Yoshinori Inoue ◽  
Chitoshi Kitamura

In an attempt to brominate 1,4-dipropoxy-9,10-anthraquinone, a mixture of products, including the title compound, C14H7BrO4, was obtained. The molecule is essentially planar (r.m.s. deviation = 0.029 Å) and two intramolecular O—H...O hydrogen bonds occur. In the crystal, the molecules are linked by weak C—H...O hydrogen bonds, Br...O contacts [3.240 (5) Å], and π–π stacking interactions [shortest centroid–centroid separation = 3.562 (4) Å], generating a three-dimensional network.


2001 ◽  
Vol 58 (1) ◽  
pp. 94-108 ◽  
Author(s):  
Craig J. Kelly ◽  
Janet M. S. Skakle ◽  
James L. Wardell ◽  
Solange M. S. V. Wardell ◽  
John N. Low ◽  
...  

Molecules of N-(4′-iodophenylsulfonyl)-4-nitroaniline, 4-O2NC6H4NHSO2C6H4I-4′ (1), are linked by three-centre I...O2N interactions into chains and these chains are linked into a three-dimensional framework by C—H...O hydrogen bonds. In the isomeric N-(4′-nitrophenylsulfonyl)-4-iodoaniline, 4-IC6H4NHSO2C6H4NO2-4′ (2), the chains generated by the I...O2N interactions are again linked into a three-dimensional framework by C—H...O hydrogen bonds. Molecules of N,N-bis(3′-nitrophenylsulfonyl)-4-iodoaniline, 4-IC6H4N(SO2C6H4NO2-3′)2 (3), lie across twofold rotation axes in space group C2/c and they are linked into chains by paired I...O=S interactions: these chains are linked into sheets by a C—H...O hydrogen bond, and the sheets are linked into a three-dimensional framework by aromatic π...π stacking interactions. In N-(4′-iodophenylsulfonyl)-3-nitroaniline, 3-O2NC6H4NHSO2C6H4I-4′ (4), there are R^2_2(8) rings formed by hard N—H...O=S hydrogen bonds and R^2_2(24) rings formed by two-centre I...nitro interactions, which together generate a chain of fused rings: the combination of a C—H...O hydrogen bond and aromatic π...π stacking interactions links the chains into sheets. Molecules of N-(4′-iodophenylsulfonyl)-4-methyl-2-nitroaniline, 4-CH3-2-O2NC6H3NHSO2C6H4I-4′ (5), are linked by N—H...O=S and C—H...O(nitro) hydrogen bonds into a chain containing alternating R^2_2(8) and R^2_2(10) rings, but there are no I...O interactions of either type. There are two molecules in the asymmetric unit of N-(4′-iodophenylsulfonyl)-2-nitroaniline, 2-O2NC6H4NHSO2C6H4I-4′ (6), and the combination of an I...O=S interaction and a hard N—H...O(nitro) hydrogen bond links the two types of molecule to form a cyclic, centrosymmetric four-component aggregate. C—H...O hydrogen bonds link these four-molecule aggregates to form a molecular ladder. Comparisons are made with structures retrieved from the Cambridge Structural Database.


2017 ◽  
Vol 73 (11) ◽  
pp. 1700-1703 ◽  
Author(s):  
Suk-Hee Moon ◽  
Joobeom Seo ◽  
Ki-Min Park

The asymmetric unit of the title compound, [Co(NO3)2(C12H12N2S)2]n, contains a bis(pyridin-3-ylmethyl)sulfane (L) ligand, an NO3−anion and half a CoIIcation, which lies on an inversion centre. The CoIIcation is six-coordinated, being bound to four pyridine N atoms from four symmetry-relatedLligands. The remaining coordination sites are occupied by two O atoms from two symmetry-related nitrate anions in a monodentate manner. Thus, the CoIIcentre adopts a distorted octahedral geometry. Two symmetry-relatedLligands are connected by two symmetry-related CoIIcations, forming a 20-membered cyclic dimer, in which the CoIIatoms are separated by 10.2922 (7) Å. The cyclic dimers are connected to each other by sharing CoIIatoms, giving rise to the formation of an infinite looped chain propagating along the [101] direction. Intermolecular C—H...π (H...ring centroid = 2.89 Å) interactions between one pair of correspondingLligands and C—H...O hydrogen bonds between theLligands and the nitrate anions occur in the looped chain. In the crystal, adjacent looped chains are connected by intermolecular π–π stacking interactions [centroid-to-centroid distance = 3.8859 (14) Å] and C—H...π hydrogen bonds (H...ring centroid = 2.65 Å), leading to the formation of layers parallel to (101). These layers are further connected through C—H...O hydrogen bonds between the layers, resulting in the formation of a three-dimensional supramolecular architecture.


2006 ◽  
Vol 62 (4) ◽  
pp. 666-675 ◽  
Author(s):  
Christopher Glidewell ◽  
John N. Low ◽  
Janet M. S. Skakle ◽  
James L. Wardell

The structures of five of the possible six isomers of (E,E)-1,4-bis(nitrophenyl)-2,3-diaza-1,3-butadiene are reported, including two polymorphs of one of the isomers. (E,E)-1,4-Bis(2-nitrophenyl)-2,3-diaza-1,3-butadiene, C14H10N4O4 (I), crystallizes in two polymorphic forms (Ia) and (Ib) in which the molecules lie across centres of inversion in space groups P21/n and P21/c, respectively: the molecules in (Ia) and (Ib) are linked into chains by aromatic π...π stacking interactions and C—H...π(arene) hydrogen bonds, respectively. Molecules of (E,E)-1-(2-nitrophenyl)-4-(3-nitrophenyl)-2,3-diaza-1,3-butadiene (II) are linked into sheets by two independent C—H...O hydrogen bonds. The molecules of (E,E)-1,4-bis(3-nitrophenyl)-2,3-diaza-1,3-butadiene (III) lie across inversion centres in the space group P21/n, and a combination of a C—H...O hydrogen bond and a π...π stacking interaction links the molecules into sheets. A total of four independent C—H...O hydrogen bonds link the molecules of (E,E)-1-(3-nitrophenyl)-4-(4-nitrophenyl)-2,3-diaza-1,3-butadiene (IV) into sheets. In (E,E)-1,4-bis(4-nitrophenyl)-2,3-diaza-1,3-butadiene (V) the molecules, which lie across centres of inversion in the space group P21/n, are linked by just two independent C—H...O hydrogen bonds into a three-dimensional framework.


2014 ◽  
Vol 70 (5) ◽  
pp. o583-o583 ◽  
Author(s):  
Yoshinobu Ishikawa

In the title compound, C10H5FO3, the non-H atoms are essentially coplanar (r.m.s. deviation = 0.0071 Å), with the largest deviation from the mean plane [0.0203 (15) Å] being found for the ring C atom in the 2-position. In the crystal, molecules are linked into a three-dimensional architectureviaC—H...O hydrogen bonds and π–π stacking interactions between the chromone units along thea-axis direction [centroid–centroid distance between the benzene and pyran rings = 3.707 (2) Å].


2014 ◽  
Vol 70 (6) ◽  
pp. 562-565 ◽  
Author(s):  
Wei Zhang ◽  
Yu-Quan Feng

A novel dinuclear bismuth(III) coordination compound, [Bi2(C7H3NO4)2(N3)2(C12H8N2)2]·4H2O, has been synthesized by an ionothermal method and characterized by elemental analysis, energy-dispersive X-ray spectroscopy, IR, X-ray photoelectron spectroscopy and single-crystal X-ray diffraction. The molecular structure consists of one centrosymmetric dinuclear neutral fragment and four water molecules. Within the dinuclear fragment, each BiIIIcentre is seven-coordinated by three O atoms and four N atoms. The coordination geometry of each BiIIIatom is distorted pentagonal–bipyramidal (BiO3N4), with one azide N atom and one bridging carboxylate O atom located in axial positions. The carboxylate O atoms and water molecules are assembledviaO—H...O hydrogen bonds, resulting in the formation of a three-dimensional supramolecular structure. Two types of π–π stacking interactions are found, with centroid-to-centroid distances of 3.461 (4) and 3.641 (4) Å.


2007 ◽  
Vol 63 (1) ◽  
pp. 101-110 ◽  
Author(s):  
Solange M. S. V. Wardell ◽  
Marcus V. N. de Souza ◽  
James L. Wardell ◽  
John N. Low ◽  
Christopher Glidewell

1-(2-Chloronicotinoyl)-2-(2-nitrophenyl)hydrazine, C12H9ClN4O3, crystallizes in three polymorphic forms, two monoclinic forms in space groups Cc (Ia) and P21 (Ib), and an orthorhombic form in space group Pbcn (Ic). In the Cc polymorph (Ia) the molecules are linked into sheets by combinations of one N—H...O and two C—H...O hydrogen bonds, while in the P21 polymorph (Ib) the molecules are linked into sheets by combinations of three hydrogen bonds, one each of N—H...O, C—H...N and C—H...O types. In the orthorhombic polymorph (Ic) the molecules are linked into a complex three-dimensional framework structure by a combination of one N—H...O, one N—H...N and three C—H...O hydrogen bonds, and an aromatic π...π stacking interaction. In the isomeric compound 1-(2-chloronicotinoyl)-2-(3-nitrophenyl)hydrazine (II) the molecules are again linked into a three-dimensional framework, this time by a combination of three hydrogen bonds, one each of N—H...O, N—H...N and C—H...O types, weakly augmented by a π...π stacking interaction. The molecules of 1-(2-chloronicotinoyl)-2-(4-nitrophenyl)hydrazine (III) are linked into sheets by a combination of three hydrogen bonds, one each of N—H...O, N—H...N and C—H...O types.


2012 ◽  
Vol 68 (11) ◽  
pp. o439-o442 ◽  
Author(s):  
Jairo Quiroga ◽  
Jaime Gálvez ◽  
Justo Cobo ◽  
Christopher Glidewell

The racemic title dipyrrolopyrrolizine compound crystallizes from dimethylformamide as a disolvate, C55H39Cl2N7O6·2C3H7NO. None of the four fused heterocyclic rings is planar; one adopts an envelope conformation, two others adopt half-chair conformations and the fourth adopts a conformation intermediate between an envelope and a half-chair. The arrangement of the ring fusions is such as to preclude the possibility of internal mirror symmetry. The three independent molecular components are weakly linked by C—H...O hydrogen bonds, and the dipyrrolopyrrolizine molecules are linked by a combination of four C—H...O and one C—H...π(arene) hydrogen bond to form a three-dimensional framework, from which the dimethylformamide solvent molecules are pendent. However, aromatic π–π stacking interactions are absent in the structure.


2014 ◽  
Vol 70 (7) ◽  
pp. 718-721
Author(s):  
Zhengliang Lu ◽  
Yuanchao Zhao ◽  
Baolian Chen ◽  
Ximing Huang ◽  
Chunhua Fan

The title compound, [MnCl2(C24H20N6)], has been synthesized and characterized based on the multifunctional ligand 2,5-bis(2,2′-bipyridyl-6-yl)-3,4-diazahexa-2,4-diene (L). The MnIIcentre is five-coordinate with an approximately square-pyramidal geometry. TheLligand acts as a tridendate chelating ligand. The mononuclear molecules are bridged into a one-dimensional chain by two C—H...Cl hydrogen bonds. These chains are assembled into a two-dimensional layer through π–π stacking interactions between adjacent uncoordinated bipyridyl groups. Furthermore, a three-dimensional supramolecular framework is attained through π–π stacking interactions between adjacent coordinated bipyridyl groups.


Sign in / Sign up

Export Citation Format

Share Document