Crystal Structure of Bovine Alpha-Chymotrypsin in Space Group P65

Chymotrypsin is a protease that is commonly used as a standard for protein crystallization and as a model system for studying serine proteases. Unliganded bovine α-chymotrypsin was crystallized at neutral pH using ammonium sulphate as the precipitant, resulting in crystals that conform to P65 symmetry with unit cell parameters that have not been reported previously. Inspection of crystallographic interfaces revealed that the major interface between any two molecules in the crystal lattice represents the interface of the biological dimer, as previously observed for crystals of unliganded α-chymotrypsin grown at low pH in space group P21.

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The crystal structure of alstonite, BaCa(CO3)2: an extraordinary example of ‘hidden’ complex twinning in large single crystals

Mineralogical Magazine ◽

10.1180/mgm.2020.61 ◽

2020 ◽

Vol 84 (5) ◽

pp. 699-704

Author(s):

Luca Bindi ◽

Andrew C. Roberts ◽

Cristian Biagioni

Keyword(s):

Crystal Structure ◽

Single Crystals ◽

Structure Determination ◽

Unit Cell ◽

Crystal Structure Determination ◽

Unit Cell Parameters ◽

Space Group ◽

Cell Parameters ◽

Structure Determinations

AbstractAlstonite, BaCa(CO3)2, is a mineral described almost two centuries ago. It is widespread in Nature and forms magnificent cm-sized crystals. Notwithstanding, its crystal structure was still unknown. Here, we report the crystal-structure determination of the mineral and discuss it in relationship to other polymorphs of BaCa(CO3)2. Alstonite is trigonal, space group P31m, with unit-cell parameters a = 17.4360(6), c = 6.1295(2) Å, V = 1613.80(9) Å3 and Z = 12. The crystal structure was solved and refined to R1 = 0.0727 on the basis of 4515 reflections with Fo > 4σ(Fo) and 195 refined parameters. Alstonite is formed by the alternation, along c, of Ba-dominant and Ca-dominant layers, separated by CO3 groups parallel to {0001}. The main take-home message is to show that not all structure determinations of minerals/compounds can be solved routinely. Some crystals, even large ones displaying excellent diffraction quality, can be twinned in complex ways, thus making their study a crystallographic challenge.

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Crystal Chemistry and High-Temperature Behaviour of Ammonium Phases NH4MgCl3·6H2O and (NH4)2Fe3+Cl5·H2O from the Burned Dumps of the Chelyabinsk Coal Basin

Minerals ◽

10.3390/min9080486 ◽

2019 ◽

Vol 9 (8) ◽

pp. 486 ◽

Cited By ~ 2

Author(s):

Andrey A. Zolotarev ◽

Elena S. Zhitova ◽

Maria G. Krzhizhanovskaya ◽

Mikhail A. Rassomakhin ◽

Vladimir V. Shilovskikh ◽

...

Keyword(s):

Crystal Structure ◽

High Temperature ◽

Unit Cell ◽

X Ray Diffraction ◽

Coal Basin ◽

Unit Cell Parameters ◽

Space Group ◽

X Ray ◽

Cell Parameters ◽

Mineral Phases

The technogenic mineral phases NH4MgCl3·6H2O and (NH4)2Fe3+Cl5·H2O from the burned dumps of the Chelyabinsk coal basin have been investigated by single-crystal X-ray diffraction, scanning electron microscopy and high-temperature powder X-ray diffraction. The NH4MgCl3·6H2O phase is monoclinic, space group C2/c, unit cell parameters a = 9.3091(9), b = 9.5353(7), c = 13.2941(12) Å, β = 90.089(8)° and V = 1180.05(18) Å3. The crystal structure of NH4MgCl3·6H2O was refined to R1 = 0.078 (wR2 = 0.185) on the basis of 1678 unique reflections. The (NH4)2Fe3+Cl5·H2O phase is orthorhombic, space group Pnma, unit cell parameters a = 13.725(2), b = 9.9365(16), c = 7.0370(11) Å and V = 959.7(3) Å3. The crystal structure of (NH4)2Fe3+Cl5·H2O was refined to R1 = 0.023 (wR2 = 0.066) on the basis of 2256 unique reflections. NH4MgCl3·6H2O is stable up to 90 °C and then transforms to the less hydrated phase isotypic to β-Rb(MnCl3)(H2O)2 (i.e., NH4MgCl3·2H2O), the latter phase being stable up to 150 °C. (NH4)2Fe3+Cl5·H2O is stable up to 120 °C and then transforms to an X-ray amorphous phase. Hydrogen bonds provide an important linkage between the main structural units and play the key role in determining structural stability and physical properties of the studied phases. The mineral phases NH4MgCl3·6H2O and (NH4)2Fe3+Cl5·H2O are isostructural with natural minerals novograblenovite and kremersite, respectively.

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Structural characterization of a novel monotreme-specific protein with antimicrobial activity from the milk of the platypus

Acta Crystallographica Section F Structural Biology Communications ◽

10.1107/s2053230x17017708 ◽

2018 ◽

Vol 74 (1) ◽

pp. 39-45 ◽

Cited By ~ 3

Author(s):

Janet Newman ◽

Julie A. Sharp ◽

Ashwantha Kumar Enjapoori ◽

John Bentley ◽

Kevin R. Nicholas ◽

...

Keyword(s):

Crystal Structure ◽

Antimicrobial Activity ◽

Mammalian Cells ◽

Unit Cell ◽

Protein Crystal ◽

Unit Cell Parameters ◽

Flag Epitope ◽

Data Set ◽

Space Group ◽

Cell Parameters

Monotreme lactation protein (MLP) is a recently identified protein with antimicrobial activity. It is present in the milk of monotremes and is unique to this lineage. To characterize MLP and to gain insight into the potential role of this protein in the evolution of lactation, the crystal structure of duck-billed platypus (Ornithorhynchus anatinus) MLP was determined at 1.82 Å resolution. This is the first structure to be reported for this novel, mammalian antibacterial protein. MLP was expressed as a FLAG epitope-tagged protein in mammalian cells and crystallized readily, with at least three space groups being observed (P1,C2 andP21). A 1.82 Å resolution native data set was collected from a crystal in space groupP1, with unit-cell parametersa= 51.2,b= 59.7,c= 63.1 Å, α = 80.15, β = 82.98, γ = 89.27°. The structure was solved by SAD phasing using a protein crystal derivatized with mercury in space groupC2, with unit-cell parametersa= 92.7,b = 73.2,c= 56.5 Å, β = 90.28°. MLP comprises a monomer of 12 helices and two short β-strands, with much of the N-terminus composed of loop regions. The crystal structure of MLP reveals no three-dimensional similarity to any known structures and reveals a heretofore unseen fold, supporting the idea that monotremes may be a rich source for the identification of novel proteins. It is hypothesized that MLP in monotreme milk has evolved to specifically support the unusual lactation strategy of this lineage and may have played a central role in the evolution of these mammals.

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Crystal structure of Ca2Zn2(V4O14) and Pb2Cd2(V3O10)(VO4) double vanadates

Powder Diffraction ◽

10.1017/s0885715618000441 ◽

2018 ◽

Vol 33 (3) ◽

pp. 216-224 ◽

Cited By ~ 1

Author(s):

V. D. Zhuravlev ◽

A. P. Tyutyunnik ◽

A. Y. Chufarov ◽

N. I. Lobachevskaya ◽

A. A. Velikodnyi

Keyword(s):

Crystal Structure ◽

Unit Cell ◽

Powder Diffraction Data ◽

Structural Refinement ◽

Unit Cell Parameters ◽

Monoclinic Symmetry ◽

Conventional Solid State Reaction ◽

Space Group ◽

X Ray ◽

Cell Parameters

Polycrystalline samples of Ca2Zn2(V4O14) (I) and Pb2Cd2(V3O10)(VO4) (II) were synthesized using the nitrate–citrate method (I) and conventional solid state reaction (II). The structural refinement based on X-ray powder diffraction data showed that the crystal structure of (I) is characterized by monoclinic symmetry with unit-cell parameters a = 6.8044(1) Å, b = 14.4876(3) Å, c = 11.2367(2) Å, β = 99.647(1)° [space group P21/c (No. 14), Z = 4], and the crystal structure of (II) is triclinic with unit-cell parameters a = 7.03813(6) Å, b = 12.9085(1) Å, c = 6.99961(5) Å, α = 90.7265(5)°, β = 96.3789(5)°, γ = 94.9530(6)°, V = 629.470(8) Å3 [space group P$\bar 1$ (No. 2), Z = 2].

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Tetra-n-butylammonium iodide: a space-group revision

Acta Crystallographica Section E Structure Reports Online ◽

10.1107/s1600536807008446 ◽

2007 ◽

Vol 63 (3) ◽

pp. o1464-o1466 ◽

Cited By ~ 7

Author(s):

Wiesław Prukała ◽

Bogdan Marciniec ◽

Maciej Kubicki

Keyword(s):

Crystal Structure ◽

Room Temperature ◽

Unit Cell ◽

Unit Cell Parameters ◽

Space Group ◽

Cell Parameters ◽

Temperature Determination

The crystal structure of tetra-n-butylammonium iodide, C16H36N+·I−, has been redetermined at room temperature and at 100 (1) K. In the low-quality (R = 0.142) room-temperature determination by Wang, Habenschuss, Xenopoulos & Wunderlich [Mol. Cryst. Liq. Cryst. Sci. Technol. Sect. A (1995), 264, 115–129], this structure was described as crystallizing in the space group C2 with Z′ = 2. Our results prove that the correct space group is C2/c (with the same unit-cell parameters as in the original determination) at both temperatures. In the crystal structure, the iodide anions fill the voids in the grid-like cationic structure. Weak C—H...I interactions (eight per anion) strengthen this packing.

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The crystal structure of cyanotrichite

Mineralogical Magazine ◽

10.1180/minmag.2015.079.2.10 ◽

2015 ◽

Vol 79 (2) ◽

pp. 321-335 ◽

Cited By ~ 4

Author(s):

Stuart J. Mills ◽

Andrew G. Christy ◽

Fernando Colombo ◽

Jason R. Price

Keyword(s):

Crystal Structure ◽

Hydrogen Bonding ◽

Local Structure ◽

Unit Cell ◽

Group Symmetry ◽

Hydrogen Atoms ◽

Unit Cell Parameters ◽

Space Group ◽

Cell Parameters ◽

Bonding Scheme

AbstractWe report the single-crystal average structure of cyanotrichite, Cu4Al2[SO4](OH)12(H2O)2, from the Maid of Sunshine mine, Arizona, USA. Cyanotrichite crystallizes in space group C2/m, with the unit-cell parameters a = 12.625(3), b = 2.8950(6), c = 10.153(2) Å and β = 92.17(3)o. All non-hydrogen atoms were located and refined to R1 = 0.0394 for all 584 observed reflections [Fo > 4σFo] and 0.0424 for all 622 unique reflections. The cyanotrichite structure consists of a principal building unit of a three-wide [Cu2Al(OH)6] ribbon of edge-sharing Cu and Al polyhedra || b, similar to that found for camerolaite. The ribbons lie in layers || (001) and between these layers, while SO4 tetrahedra and H2O molecules form rods running || b. A hydrogen-bonding scheme is also proposed.A sample of cyanotrichite from the Cap Garonne mine, Le Pradet, France, showed a 4b superstructure with the following unit cell: space group P2/m, a = 12.611(2) Å, b = 11.584(16) = 4 × 2.896(4) Å, c = 10.190(1) Å and β = 92.29(6)o. The supercell could not be refined in detail, but nevertheless imposes constraints on the local structure in that while the space-group symmetry prevents full order of SO4 and H2O in the 4b supercell, it requires that the sequence of species along any given rod is [-SO4-SO4-(H2O)2-(H2O)2-] rather than [-SO4-(H2O)2-SO4-(H2O)2-].

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The crystal structure of trisodium hexachlororhodate (Na3RhCl6)

Powder Diffraction ◽

10.1017/s0885715618000155 ◽

2018 ◽

Vol 33 (1) ◽

pp. 62-65

Author(s):

Martin Etter

Keyword(s):

Crystal Structure ◽

Powder Diffraction ◽

Structure Type ◽

Unit Cell ◽

Unit Cell Parameters ◽

Space Group ◽

X Ray ◽

Cell Parameters

Commercially available trisodium hexachlororhodate (Na3RhCl6) was dehydrated and characterized by laboratory X-ray powder diffraction. The crystal structure is isostructural to the Na3CrCl6 structure type with space group P$\bar 31$c. Unit-cell parameters are a = 6.8116(1) Å, c = 11.9196(2) Å, V = 478.95(2) Å3, and Z = 2.

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Crystal structure and powder data of davidite-type La2Ti10.27Ga9.63O38

Powder Diffraction ◽

10.1017/s0885715600010289 ◽

1999 ◽

Vol 14 (1) ◽

pp. 36-41 ◽

Cited By ~ 1

Author(s):

A. Meden ◽

D. Kolar ◽

S. Škapin

Keyword(s):

Crystal Structure ◽

Rietveld Refinement ◽

Structure Type ◽

Unit Cell ◽

Unit Cell Parameters ◽

Space Group ◽

Cell Parameters

The structure type of La2Ti10.27Ga9.63O38 was revealed by a search-match using the PDF. A successful Rietveld refinement (Rp=8.9, Rwp=13.3, RB=4.20) confirmed the structure to be rhombohedral (space group R3¯, No. 148) with the refined unit cell parameters a=9.1878(1) Å, α=68.458(1)°, and V=646.374(1) Å3. The structure is compared to other compounds of the davidite type, and the observed and calculated powder data are given.

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Crystal structure and topological affinities of magbasite, KBaFe3+Mg7Si8O22(OH)2F6: a trellis structure related to amphibole and carpholite

Mineralogical Magazine ◽

10.1180/minmag.2014.078.1.03 ◽

2014 ◽

Vol 78 (1) ◽

pp. 29-45 ◽

Cited By ~ 3

Author(s):

M. D. Welch ◽

R. H. Mitchell ◽

A. R. Kampf ◽

A. R. Chakhmouradian ◽

D. Smith ◽

...

Keyword(s):

Crystal Structure ◽

Unit Cell ◽

Unit Cell Parameters ◽

Carbonatite Complex ◽

Orthorhombic Space Group ◽

Space Group ◽

Cell Parameters ◽

Structural Relations ◽

Final Agreement

AbstractThe crystal structure of magbasite from the Eldor carbonatite complex, Quebec, Canada, has been determined and indicates that the currently accepted formula should be revised to KBaFe3+Mg7Si8O22(OH)2F6. Magbasite is orthorhombic, space group Cmme (Cmma), with unit-cell parameters a 18.9506(3) Å, b 22.5045(3) Å, c 5.2780(1) Å, V 2250.93(6) Å3 (Z = 4). The structure has been solved and refined to final agreement indices R1 = 0.026, wR2 = 0.052, GooF = 1.116 for a total of 2379 unique reflections, and is a new kind of trellis motif related to amphibole and carpholite topologies. An amphibole-like I-beam ‖(100) of edge-sharing octahedrally-coordinated M(1,2,3) sites, which are filled by Mg, is sandwiched between double-chains of SiO4 tetrahedra ‖c. This I-beam is connected to side-ribbons ‖(010) of edge-sharing (Mg,Fe2+)O4(OH,F)2 and Fe3+O4(OH)2 octahedra to form a tunnelled box or trellis structure very like that of carpholite, for which the I-beams are pyroxene-like. K occupies a tunnel site analogous to the A site of amphibole. Ba occupies a cavity site at the corners where the I-beam and side-ribbon meet, and corresponds to the A site of carpholite. The structural relations between magbasite and carpholite are discussed.

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Preparation and crystal structure of SbV1.50InIII0.50(PO4)3 and (SbV0.50InIII0.50)P2O7

Powder Diffraction ◽

10.1154/1.2955583 ◽

2008 ◽

Vol 23 (3) ◽

pp. 232-240

Author(s):

Abderrahim Aatiq ◽

Rachid Bakri ◽

Aaron Richard Sakulich

Keyword(s):

Crystal Structure ◽

Solid State ◽

Room Temperature ◽

Rietveld Method ◽

Monoclinic Space Group ◽

Unit Cell Parameters ◽

Orthorhombic System ◽

Space Group ◽

X Ray ◽

Cell Parameters

Synthesis and structure of two phosphates belonging to the ternary Sb2O5–In2O3–P2O5 system are realized. Structures of SbV1.50InIII0.50(PO4)3 and (SbV0.50InIII0.50)P2O7 phases, obtained by solid state reaction in air at 950 °C, were determined at room temperature from X-ray powder diffraction using the Rietveld method. SbV1.50InIII0.50(PO4)3 have a monoclinic (space group P21/n) distortion of the Sc2(W O4)3-type framework. Its structure is constituted by corner-shared SbO6 or InO6 octahedra and PO4 tetrahedra. Monoclinic unit cell parameters are a=11.801(2) Å, b=8.623(1) Å, c=8.372(1) Å, and β=90.93(1)°. (Sb0.50In0.50)P2O7 is isotypic with (Sb0.50Fe0.50)P2O7 and crystallizes in orthorhombic system (space group Pna21) with a=7.9389(1) Å, b=16.0664(2) Å, and c=7.9777(1) Å. Its structure is built up from corner-shared SbO6 or InO6 octahedra and P2O7 groups (two group-types). Each P2O7 group shares its six vertices with three SbO6 and three InO6 octahedra, and each octahedron is connected to six P2O7 groups.

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