scholarly journals Structure of the interleukin-2 tyrosine kinase Src homology 2 domain; comparison between X-ray and NMR-derived structures

Author(s):  
Raji E. Joseph ◽  
Nathaniel D. Ginder ◽  
Julie A. Hoy ◽  
Jay C. Nix ◽  
D. Bruce Fulton ◽  
...  

The crystal structure of the interleukin-2 tyrosine kinase Src homology domain (Itk SH2) is described and it is found that unlike in studies of this domain using NMR spectroscopy,cis–trans-prolyl isomerization is not readily detected in the crystal structure. Based on similarities between the Itk SH2 crystal form and thecisform of the Itk SH2 NMR structure, it is concluded that it is likely that the prolyl imide bond at least in part adopts thecisconformation in the crystal form. However, the lack of high-resolution data and the dynamic nature of the proline-containing loop mean that the precise imide-bond conformation cannot be determined and prolylcis–transisomerization in the crystal cannot be ruled out. Given the preponderance of structures that have been solved by X-ray crystallography in the Protein Data Bank, this result supports the notion that prolyl isomerization in folded proteins has been underestimated among known structures. Interestingly, while the precise status of the proline residue is ambiguous, Itk SH2 crystallizes as a domain-swapped dimer. The domain-swapped structure of Itk SH2 is similar to the domain-swapped SH2 domains of Grb2 and Nck, with domain swapping occurring at the β-meander region of all three SH2 domains. Thus, for Itk SH2 structural analysis by NMR spectroscopy and X-ray crystallography revealed very different structural features: proline isomerizationversusdomain-swapped dimerization, respectively.

2018 ◽  
Vol 74 (12) ◽  
pp. 1629-1634 ◽  
Author(s):  
Abdellah N'ait Ousidi ◽  
Moulay Youssef Ait Itto ◽  
Aziz Auhmani ◽  
Abdelkhalek Riahi ◽  
Anthony Robert ◽  
...  

The synthesis of three new polysubstituted monoterpenic thiazolidin-4-ones, namely (Z)-3-methyl-2-{(E)-[(1R,4R)-1,7,7-trimethylbicyclo[2.2.1]heptan-2-ylidene]hydrazinylidene}thiazolidin-4-one, C14H21N3OS (2), (2Z,5Z)-5-[(dimethylamino)methylidene]-2-{(E)-[(1R,4R)-1,7,7-trimethylbicyclo[2.2.1]heptan-2-ylidene]hydrazinylidene}thiazolidin-4-one, C16H24N4OS (3), and (2Z,5Z)-5-[(dimethylamino)methylidene]-3-methyl-2-{(E)-[(1R,4R)-1,7,7-trimethylbicyclo[2.2.1]heptan-2-ylidene]hydrazinylidene}thiazolidin-4-one, C17H26N4OS (4), is reported, starting from the corresponding thiosemicarbazones obtained from naturally occurring (R)-camphor. All the newly obtained thiazolidin-4-ones have been fully characterized by HRMS and 1H and 13C (1D and 2D) NMR spectroscopy. Two of them, i.e. 2 and 3, were identified by single-crystal X-ray crystallography, confirming the synthetic pathway and the spectroscopic analyses. In 3, there are two roughly identical molecules within the asymmetric unit with the same absolute configuration. These two molecules are linked through N—H...O hydrogen bonds, building an R 2 2(8) graph-set motif.


2020 ◽  
Vol 8 (40) ◽  
pp. 14208-14218
Author(s):  
Hongbo Wang ◽  
Jinnan Huo ◽  
Hongbo Tong ◽  
Xuehong Wei ◽  
Ying Zhang ◽  
...  

A novel electroluminescent material based on pyrrolo[3,2-b]pyrrole as skeleton and donor group and dimesitylborons as accept groups has been synthesized and characterized by elemental analysis, mass spectrometry, NMR spectroscopy and X-ray crystallography.


2010 ◽  
Vol 65 (2) ◽  
pp. 128-134 ◽  
Author(s):  
Farzin Marandi ◽  
Zahra Nikpey ◽  
Jia Hao Goh ◽  
Hoong-Kun Fun

Three substituted 2,2'-bipyridine adducts of lead(II) thenoyltrifluoroacetonate, [Pb(4,4'-dm-2,2’- bpy)(ttfa)2]2, 1, [Pb(5,5' -dm-2,2’-bpy)(ttfa)2]2, 2, and [Pb(4,4'-dmo-2,2’-bpy)(ttfa)2], 3, (4,4’ -dm- 2,2’-bpy, 5,5’-dm-2,2’-bpy, 4,4’-dmo-2,2’-bpy and ttfa are the abbreviations for 4,4’-dimethyl-, 5,5’-dimethyl-, and 4,4’-dimethoxy-2,2’-bipyridine, and thenoyltrifluoroacetonate, respectively) have been synthesized, characterized by elemental and thermal analysis, IR and 1H- and 13C-NMR spectroscopy, and studied by X-ray crystallography. The supramolecular features in these complexes are guided/controlled by weak directional intermolecular interactions.


2004 ◽  
Vol 59 (3) ◽  
pp. 291-297 ◽  
Author(s):  
Andreas Sofetis ◽  
Giannis S. Papaefstathiou ◽  
Aris Terzis ◽  
Catherine P. Raptopoulou ◽  
Theodoros F. Zafiropoulos

The reaction of Ga2(SO4)3·18H2O and excess 2,2′:6′,2″-terpyridine (terpy) in MeOH / H2O leads to [Ga(OH)(SO4)(terpy)(H2O)]·H2O (1·H2O] in good yield. The structure of the complex has been determined by single-crystal X-ray crystallography. The GaIII atom in 1·H2O is 6-coordinate and ligation is provided by one terdentate terpy molecule, one monodentate sulfate, one terminal hydroxide and one terminal H2O molecule; the coodination polyhedron about the metal is described as a distorted octahedron. There is an extensive hydrogen-bonding network in the crystal structure which generates corrugated layers parallel to bc. The new complex was characterized by IR and 1H NMR spectroscopy. The spectroscopic data are discussed in terms of the nature of bonding


2017 ◽  
Vol 72 (7) ◽  
pp. 523-525
Author(s):  
Chang-Jiu Wang ◽  
Xiu-Li Wu ◽  
Xiu-Fang Ma ◽  
Ai-Quan Jia ◽  
Qian-Feng Zhang

AbstractTreatment of [Ru(acac)3] (acac−=acetylacetonate) with (2,4,5-Me3C6H2)MgBr, followed by column chromatography in air, afforded the homoleptic tetraaryl-ruthenium(IV) complex [Ru(2,4,5-Me3C6H2)4] (1) in moderate yield. The product was characterized by proton NMR spectroscopy and microanalyses. Its crystal structure has also been established by X-ray crystallography.


2005 ◽  
Vol 60 (3) ◽  
pp. 289-293 ◽  
Author(s):  
Ali Ramazani ◽  
Ali Morsali ◽  
Leila Dolatyari ◽  
Bijan Ganjeie

The mercury(II) complexes of 2,2′-bipyridine (bpy), [Hg(bpy)(NO2)2], [Hg(bpy)(NO2) (CH3COO)], and [Hg(bpy)(NO2)(NCS)] have been synthesized and characterized by elemental analysis, IR, 1H NMR and 13C NMR spectroscopy. The structure of [Hg(bpy)(NO2)2] has been confirmed by X-ray crystallography. The complex is a monomer and the Hg atom has an unsymmetrical six-coordinate geometry, formed by two nitrogen atoms of the bpy ligand and four oxygen atoms of the two nitrite anions. There is a short intermolecular π-π stacking interaction between parallel aromatic rings


2001 ◽  
Vol 56 (12) ◽  
pp. 1369-1372 ◽  
Author(s):  
Jarkko Pietikäinen ◽  
Risto S. Laitinen ◽  
Jari Konu ◽  
Jussi Valkonen

AbstractThe reaction of hexamethyldisilane with tellu­rium tetrachloride in carbon disulfide afforded polymeric (MeTeCl3)n (1) that was characterized by TOF ES mass spectroscopy, 125Te NMR spectroscopy, and X-ray crystallography. Pale brown, air-and moisture-sensitive crystals of 1 are monoclinic, space group P21/n with a = 1030.69(5), b = 643.61(2), c = 1041.68(5) pm, ß = 119.236(5)°, V = 0.60299(5) nm3, and Z = 4. The crystal structure consists of infinite helical chains of the MeTeCl3 units linked by bridging chlorine atoms. The polymeric chains are linked together by Te···Cl and Cl···Cl close contacts. The pos­sible routes for the formation of (MeTeCl3)n are discussed.


2016 ◽  
Vol 71 (9) ◽  
pp. 959-965 ◽  
Author(s):  
Farzin Marandi ◽  
Keyvan Moeini ◽  
Hadi Amiri Rudbari

AbstractThree new compounds of zinc(II) and cadmium(II) with the ligand 4,4′-dimethoxy-2,2′-bipyridine (4,4′-dmo-2,2′-bpy), including cis-[Zn(4,4′-dmo-2,2′-bpy)2(SCN)2] (1), cis-[Cd(4,4′-dmo-2,2′-bpy)2(SCN)2] (2), and [Cd3(4,4′-dmo-2,2′-bpy)3(N3)5(OAc)]n (3), have been obtained as white single crystals by the branched tube method and characterized by elemental analysis, FT-IR and 1H, 13C NMR spectroscopy, and X-ray crystallography. Single-crystal structure analyses of the isostructural complexes 1 and 2 showed distorted octahedral geometry for zinc(II) and cadmium(II) with ZnN6 and CdN6 environments. Complex 3 reveals a rare coordination polymer containing octahedrally coordinated cadmium(II) expanding to chains by two different bridging modes, including Cd‒O‒C‒O‒Cd and Cd‒N‒Cd.


2017 ◽  
Vol 72 (10) ◽  
pp. 759-762 ◽  
Author(s):  
Marion Graf ◽  
Peter Mayer ◽  
Hans-Christian Böttcher

AbstractTreatment of hydrated ruthenium(III) chloride with tetra-2-pyridyl-1,4-pyrazine (tppz) in refluxing ethoxyethanol afforded the homoleptic dinuclear complex [(tppz)Ru(μ-tppz)Ru(tppz)]4+ (1) besides small amounts of the species [Ru(tppz)2]2+. The title complex 1 was obtained as purple crystals and characterized as its hexafluoridophosphate salt by NMR spectroscopy, mass spectrometry and microanalyses. The molecular structure of 1(PF6)4 has been established by X-ray crystallography.


2020 ◽  
Vol 17 (1(Suppl.)) ◽  
pp. 0272
Author(s):  
Ahmed Shukkur

       Our work included a synthesis of three new imine derivatives—1,3-thiazinan-4-one, 1,3-oxazinan-6-one and 1,3-oxazepin-4,7-dione—which contained an adamantyl fragment. These were produced via the condensation of the Schiff`s base (E)-N-(adamantan-1-yl)-1-(3-aryl)methanimine with 3-mercaptopropanoic acid; 3-chloropropanoic acid; and maleic, citraconic anhydride, respectively. These new imines were prepared via the condensation of adamantan-1-ylamine and 3-nitro-, 3-bromobenzaldehyde in n-BuOH. We obtained a good yield of products. FTIR, 1H NMR spectroscopy and C.H.N.S analysis were used to diagnostic the products. The molecular structure of (E)-N-(adamantan-1-yl)-1-(3-nitrophenyl)methanimine was confirmed by X-ray crystallography analysis.  


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