X-ray studies on crystalline complexes involving amino acids and peptides. XXXIX. Crystal structures of malonic acid complexes of DL- and L-histidine. Preservation of aggregation pattern on reversal of chirality

2002 ◽  
Vol 58 (4) ◽  
pp. 734-739 ◽  
Author(s):  
N.T. Saraswathi ◽  
M. Vijayan
Keyword(s):  
Amino Acid ◽  
Malonic Acid ◽  
Unit Cell Parameters ◽  
X Ray ◽  
Space Groups ◽  
Cell Parameters ◽  
Aggregation Pattern ◽  
The Cost ◽  
First Time ◽  
Positively Charged

The malonic acid complexes of DL- and L-histidine are made up of zwitterionic positively charged histidinium ions and semimalonate (hydrogen malonate) ions. They crystallise in space groups P21/n and P21, respectively, with nearly the same unit-cell parameters. The molecules aggregate in the two complexes in a remarkably similar manner. The two sets of crystallographically independent molecules are related by a pseudo-glide plane. This pseudo-symmetry is almost exact except in the case of the α-carboxylate group and, to some extent, the α-C and the α-N atoms. Preservation of the aggregation pattern to such an extent on the reversal of chirality of half the amino-acid molecules is observed for the first time in amino-acid complexes. This is achieved at the cost of considerable conformational strain in one of the two histidinium ions in the L-histidine complex.

X-ray studies on crystalline complexes involving amino acids and peptides. XL. Conformational variability, recurring and new features of aggregation, and effect of chirality in the malonic acid complexes of DL- and L-arginine

2002 ◽  
Vol 58 (6) ◽  
pp. 1051-1056 ◽  
Author(s):  
N. T. Saraswathi ◽  
M. Vijayan
Keyword(s):  
Amino Acids ◽  
Hydrogen Bonding ◽  
Amino Acid ◽  
Crystal Structures ◽  
Malonic Acid ◽  
Conformational Flexibility ◽  
X Ray ◽  
Conformational Variability ◽  
Aggregation Pattern ◽  
Positively Charged

The crystal structures of the complexes of malonic acid with DL- and L-arginine, which contain positively charged argininium ions and negatively charged semimalonate ions, further demonstrate the conformational flexibility of amino acids. A larger proportion of folded conformations than would be expected on the basis of steric consideration appears to occur in arginine, presumably because of the requirements of hydrogen bonding. The aggregation pattern in the DL-arginine complex bears varying degrees of resemblance to patterns observed in other similar structures. An antiparallel hydrogen-bonded dimeric arrangement of arginine, and to a lesser extent lysine, is a recurring motif. Similarities also exist among the structures in the interactions with this motif and its assembly into larger features of aggregation. However, the aggregation pattern observed in the L-arginine complex differs from any observed so far, which demonstrates that all the general patterns of amino-acid aggregation have not yet been elucidated. The two complexes represent cases where the reversal of the chirality of half the amino-acid molecules leads to a fundamentally different aggregation pattern.

The structures of marialite (Me6) and meionite (Me93) in space groups P42/n and I4/m, and the absence of phase transitions in the scapolite series

2011 ◽  
Vol 26 (2) ◽  
pp. 119-125 ◽  
Author(s):  
Sytle M. Antao ◽  
Ishmael Hassan
Keyword(s):  
Phase Transitions ◽  
High Resolution ◽  
Crystal Structures ◽  
Unit Cell ◽  
X Ray Diffraction ◽  
Unit Cell Parameters ◽  
X Ray ◽  
Space Groups ◽  
Cell Parameters ◽  
The Mean

The crystal structures of marialite (Me6) from Badakhshan, Afghanistan and meionite (Me93) from Mt. Vesuvius, Italy were obtained using synchrotron high-resolution powder X-ray diffraction (HRPXRD) data and Rietveld structure refinements. Their structures were refined in space groups I4/m and P42/n, and similar results were obtained. The Me6 sample has a formula Ca0.24Na3.37K0.24[Al3.16Si8.84O24]Cl0.84(CO3)0.15, and its unit-cell parameters are a=12.047555(7), c=7.563210(6) Å, and V=1097.751(1) Å3. The average ⟨T1-O⟩ distances are 1.599(1) Å in I4/m and 1.600(2) Å in P42/n, indicating that the T1 site contains only Si atoms. In P42/n, the average distances of ⟨T2-O⟩=1.655(2) and ⟨T3-O⟩=1.664(2) Å are distinct and are not equal to each other. However, the mean ⟨T2,3-O⟩=1.659(2) Å in P42/n and is identical to the ⟨T2′-O⟩=1.659(1) Å in I4/m. The ⟨M-O⟩ [7]=2.754(1) Å (M site is coordinated to seven framework O atoms) and M-A=2.914(1) Å; these distances are identical in both space groups. The Me93 sample has a formula of Na0.29Ca3.76[Al5.54Si6.46O24]Cl0.05(SO4)0.02(CO3)0.93, and its unit-cell parameters are a=12.19882(1), c=7.576954(8) Å, and V=1127.535(2) Å3. A similar examination of the Me93 sample also shows that both space groups give similar results; however, the C–O distance is more reasonable in P42/n than in I4/m. Refining the scapolite structure near Me0 or Me100 in I4/m forces the T2 and T3 sites (both with multiplicity 8 in P42/n) to be equivalent and form the T2′ site (with multiplicity 16 in I4/m), but ⟨T2-O⟩ is not equal to ⟨T3-O⟩ in P42/n. Using different space groups for different regions across the series implies phase transitions, which do not occur in the scapolite series.

scholarly journals Synthesis, Crystal Structure, and Solubility Analysis of a Famotidine Cocrystal

Crystals ◽  
2019 ◽  
Vol 9 (7) ◽  
pp. 360 ◽  
Author(s):  
Yan Zhang ◽  
Zhao Yang ◽  
Shuaihua Zhang ◽  
Xingtong Zhou
Keyword(s):  
Crystal Structure ◽  
Malonic Acid ◽  
X Ray Diffraction ◽  
Unit Cell Parameters ◽  
H2 Receptor Antagonist ◽  
Single Crystal Diffraction ◽  
Intermolecular Hydrogen Bonds ◽  
X Ray ◽  
Cell Parameters ◽  
Cocrystal Structure

A novel cocrystal of the potent H2 receptor antagonist famotidine (FMT) was synthesized with malonic acid (MAL) to enhance its solubility. The cocrystal structure was characterized by X-ray single crystal diffraction, and the asymmetry unit contains one FMT and one MAL connected via intermolecular hydrogen bonds. The crystal structure is monoclinic with a P21/n space group and unit cell parameters a = 7.0748 (3) Å, b = 26.6502 (9) Å, c = 9.9823 (4) Å, α = 90, β = 104.2228 (12), γ = 90, V = 1824.42 (12) Å3, and Z = 4. The cocrystal had unique thermal, spectroscopic, and powder X-ray diffraction (PXRD) properties that differed from FMT. The solubility of the famotidine-malonic acid cocrystal (FMT-MAL) was 4.2-fold higher than FMT; the FAM-MAL had no change in FMT stability at high temperature, high humidity, or with illumination.

scholarly journals Crystallization and preliminary X-ray diffraction analysis ofBacillus subtilisYwfE, anL-amino-acid ligase

2012 ◽  
Vol 68 (2) ◽  
pp. 203-206 ◽  
Author(s):  
Takeo Tsuda ◽  
Tomomi Suzuki ◽  
Shuichi Kojima
Keyword(s):  
Amino Acid ◽  
Diffusion Method ◽  
Dependent Manner ◽  
Asymmetric Unit ◽  
X Ray Diffraction ◽  
Hanging Drop ◽  
Unit Cell Parameters ◽  
Data Set ◽  
X Ray ◽  
Cell Parameters

Bacillus subtilisYwfE, an L-amino-acid ligase, catalyzes the formation of an α-dipeptide from L-amino acids in an ATP-dependent manner. In order to elucidate the substrate-recognition mode and the reaction mechanism of this ligase, native and selenomethionine-derivatized (SeMet) crystals of YwfE in the presence of ADP, MgCl2and the dipeptide L-Ala-L-Gln were obtained using the hanging-drop vapour-diffusion method. These crystals diffracted to 1.9 and 2.8 Å resolution, respectively. Preliminary SAD phase calculations using the data set from the SeMet crystal suggested that the crystal belonged to the hexagonal space groupP6522, with unit-cell parametersa=b= 90.85,c = 250.31 Å, and contained one molecule in the asymmetric unit with a solvent content of 57.3%.

The crystal structure of veenite

2017 ◽  
Vol 81 (2) ◽  
pp. 355-368 ◽  
Author(s):  
Dan Topa ◽  
Emil Makovicky
Keyword(s):  
Crystal Structure ◽  
Single Crystal ◽  
Type Locality ◽  
Double Layers ◽  
Unit Cell Parameters ◽  
Single Crystal Diffraction ◽  
X Ray ◽  
Cell Parameters ◽  
First Time ◽  
Pb Substitution

AbstractThe crystal structure of veenite is reported for the first time from a sample from the type locality of Madoc (Ontario, Canada). It has been solved and refined by X-ray single-crystal diffraction on the basis of 4973 observed reflections (with Fo > 4σ(Fo)) with a final R1 = 0.0396. Veenite is monoclinic P21, with unit-cell parameters a = 8.429(2), b = 26.069(5), c = 8.962(2) Å, β = 117.447(2)o. The bulk veenite composition is Ag0.15Pb16.029Sb8.836As6.99S39.95 (for Z = 1) corresponding to N = 4.09 (Me8NS8N + 8, theoretical value is 4.0), with the percentage of the Ag-(As,Sb) substituted end-member only equal to 3.51 mol.%, i.e., a nearly pure Pb-Sb-As sulfosalt. The crystal structure is typical for the N = 4 sartorite homologue, with zig-zag walls of trigonal coordination prisms of Pb which separate slabs of diagonally oriented double-layers populated by Sb and As with partial Pb substitution. Orientation of three-membered crankshaft chains formed by strong (As,Sb) – S bonds on the two surfaces of double-layers differs substantially from that in dufrénoysite, which is a pure Pb-As (N = 4) sulfosalt.

scholarly journals Structural Reassignment of Koetjapic Acid following X-ray Crystallography and NMR Spectroscopy

2017 ◽  
Vol 12 (7) ◽  
pp. 1934578X1701200 ◽  
Author(s):  
Saifullah Abubakar ◽  
Vikneswaran Murugaiyah ◽  
Chin-Hoe Teh ◽  
Kit-Lam Chan
Keyword(s):  
Spectroscopic Data ◽  
Strong Support ◽  
Chair Conformation ◽  
Unit Cell Parameters ◽  
Orthorhombic Crystal ◽  
Dioic Acid ◽  
X Ray ◽  
Cell Parameters ◽  
X Ray Crystallography ◽  
First Time

The crystal structure and absolute configuration of koetjapic acid were unambiguously reassigned by X-ray crystallography with strong support from NMR spectroscopic data. The acid contained 9 quaternary carbon atoms existing as an orthorhombic crystal with a space group of P21 21 21 and unit cell parameters of a = 7.6641(2), b = 14.6844(4) and c = 23.9316(6). Ring A adopted a chair conformation, ring B has an envelope conformation, whilst ring C assumed a half-chair and D displayed a chair conformation. The absolute configurations at C1 ( R), C5 ( R), C7 ( S), C10 ( S), C13 ( R), C14 ( R), C17 ( S) and C18 ( S) were assigned for the first time. The X-ray crystal of koetjapic acid was therefore reassigned as 3,4-seco-olean-4(23),12-diene-3,30-dioic acid. A plausible biogenetic synthetic pathway for compound 1 is also proposed.

X-ray powder diffraction data for the N-acylamino acids: ortho, meta, and para-methyl hippuric acids

2016 ◽  
Vol 31 (3) ◽  
pp. 242-247
Author(s):  
Gerzon E. Delgado ◽  
Marilia Guillén ◽  
Jeans W. Ramírez ◽  
Asiloé J. Mora ◽  
Jines E. Contreras ◽  
...  
Keyword(s):  
Powder Diffraction ◽  
Diffraction Data ◽  
Powder Diffraction Data ◽  
Unit Cell Parameters ◽  
Space Group ◽  
X Ray ◽  
Space Groups ◽  
Cell Parameters ◽  
Methylhippuric Acid ◽  
Diffraction Peaks

N-acylamino acid isomers: ortho, meta, and para-methylhippuric acids, are specific xylene metabolites. Here, we report X-ray powder diffraction data, unit-cell parameters, and space groups for the three isomer (C10H11NO3), [ortho-methylhippuric acid 2 mHA, monoclinic P21/n cell, a = 8.522(1), b = 10.443(1), c = 10.734(1) Å, β = 92.43(1)°, V = 954.5(1) Å3; meta-methylhippuric acid 3 mHA, monoclinic C2/c cell a = 20.0951(2), b = 10.485(1), c = 10.074(2) Å, β = 119.08(1)°, V = 1933.9(1) Å3; para-methylhippuric acid 4 mHA, orthorhombic P212121 cell, a = 5.1794(7), b = 8.279(1), c = 22.276(2) Å, V = 955.2(2) Å3], space group. In each case, all measured diffraction peaks were indexed and are consistent with the corresponding space group.

Crystallization and preliminary X-ray diffraction studies of the carboxylesterase EST2 from Alicyclobacillus acidocaldarius

1999 ◽  
Vol 55 (7) ◽  
pp. 1348-1349 ◽  
Author(s):  
Giuseppina De Simone ◽  
Giuseppe Manco ◽  
Stefania Galdiero ◽  
Angela Lombardi ◽  
Mosè Rossi ◽  
...  
Keyword(s):  
Ammonium Sulfate ◽  
Unit Cell ◽  
X Ray Diffraction ◽  
Unit Cell Parameters ◽  
Data Set ◽  
Synchrotron Source ◽  
X Ray ◽  
Cell Parameters ◽  
Alicyclobacillus Acidocaldarius ◽  
First Time

EST2, a thermophilic carboxylesterase from Alicyclobacillus acidocaldarius, belonging to the HSL group of the esterase/lipase superfamily, has been crystallized for the first time. Ammonium sulfate was used as a precipitant and the crystallization proceeded at pH 7.8. The crystals belong to space group P41212 or its enantiomorph P43212, with unit-cell parameters a = b = 78.8, c = 106.4 Å. A complete data set has been collected at the synchrotron source Elettra in Trieste to 2.4 Å resolution, using a single frozen crystal.

Synthesis, Characterization, Fluorescence and Antibacterial Activity of the Re(VII) Complex [ReO3(phen)(H2PO4)]・H2O

2012 ◽  
Vol 67 (11) ◽  
pp. 1178-1184 ◽  
Author(s):  
Ahlem Maalaoui ◽  
Olfa B. Said ◽  
Samah T. Akriche ◽  
Salem S. Al-Deyab ◽  
Mohamed Rzaigui
Keyword(s):  
Thermal Stability ◽  
Spectroscopic Properties ◽  
Monoclinic Space Group ◽  
Coordination Geometry ◽  
Unit Cell Parameters ◽  
Neutral Complex ◽  
X Ray ◽  
Cell Parameters ◽  
Acid Ligand ◽  
First Time

Single crystals of a Re(VII) complex, the dihydrogenophosphato phenanthroline trioxo-rhenium monohydrate of formula [ReO3(phen)(H2PO4)]⋅H2O (phen=1,10-phenanthroline), were prepared in aqueous solution. X-Ray analysis shows that it crystallizes in the monoclinic space group P21/c with the unit cell parameters: a=8.611(2), b=13.881(2), c=14.502(4) Å , β =120:87(2)°, V =1487.9(6) Å3 and Z = 4. In the neutral complex, the rhenium is in the oxidation state +VII, coordinated by two nitrogen atoms of the bidentate phen, three terminal oxygen atoms and, for the first time, one oxygen atom of the mono-deprotonated phosphoric acid ligand H2PO-4 , forming a squarebased bipyramidal coordination geometry. The thermal stability, IR, UV/Vis and fluorescence spectroscopic properties are given. The complex shows antimicrobial activity against five different microbes.

New Occurrence of Clausthalite (PbSe) in the Sudetes (SW Poland)

Mineralogia ◽  
2006 ◽  
Vol 37 (2) ◽  
pp. 123-132 ◽  
Author(s):  
Antoni Muszer ◽  
Adam Szuszkiewicz ◽  
Krzysztof Łobos
Keyword(s):  
X Ray Diffraction ◽  
Unit Cell Parameters ◽  
X Ray ◽  
Cell Parameters ◽  
Rock Fragments ◽  
Mineral Structure ◽  
Sw Poland ◽  
Mining Works ◽  
First Time ◽  
Reflectance Measurements

New Occurrence of Clausthalite (PbSe) in the Sudetes (SW Poland)The presence of clausthalite in the area of old mining works near Dziećmorowice in the Sowie Mts (SW Poland) is reported here for the first time. The identification of the clausthalite is based on macro- and microscopic observations, reflectance measurements, chemical analyses and X-ray diffraction data. The clausthalite, together with uraninite, forms veinlets in a breccia comprising <50% calc-silicate rock fragments. Different polishing hardnesses suggest some variation in the mineral structure of individual clausthalite grains. Chemical spot analyses do not reveal elements other than Pb and Se though calculated unit-cell parameters may suggest minor substitution of S for Se.

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