Rational Design of a Porous Supramolecular Peptide Framework (SPF): A Crystalline Tetraproline in the Polyproline II Conformation

Herein, we present the first high resolution single crystal structure of an unfunctionalized tetrameric proline in the poly-proline II conformation. This rationally designed oligoproline tetramer, self-assembles to form a permanently porous crys-talline supramolecular peptide framework (SPF). Thermal activation, guest inclusion and thermally induced release of chemical guests have been demonstrated for this novel system. This discovery provides a conclusive insight into the pre-viously ambiguous conformation of short oligoprolines and will allow for the further development of proline-based pep-tide linkers in the rational design of SPFs and metal-peptide frameworks.

Download Full-text

Bond catastrophes in rhodium complexes: experimental charge-density studies of [Rh(C7H8)(P t Bu3)Cl] and [Rh(C7H8)(PCy3)Cl]

Acta Crystallographica Section B Structural Science ◽

10.1107/s0108768110031496 ◽

2010 ◽

Vol 66 (5) ◽

pp. 503-514 ◽

Cited By ~ 12

Author(s):

Hazel A. Sparkes ◽

Adrian B. Chaplin ◽

Andrew S. Weller ◽

Judith A. K. Howard

Keyword(s):

High Resolution ◽

Transition Metal ◽

Single Crystal ◽

Charge Density ◽

Rhodium Complexes ◽

Metal Compounds ◽

Potential Applications ◽

Resolution Single ◽

Experimental Charge Density ◽

Insight Into

Rhodium complexes have potential uses in both catalysis and promoting the cleavage of C—C bonds. In order to further our understanding of these species and their potential applications, it is vital to obtain insight into the bonding within the species, particularly the Rh—C interactions, and to this end experimental charge-density studies have been undertaken on the title complexes. High-resolution single-crystal datasets to sin θ/λ = 1.06 Å−1 were obtained at 100 K and analysed using Bader's `Atoms in Molecules' (AIM) approach. The results of the studies have provided unique insights into the bonding involving rhodium and highlight the importance of undertaking such investigations for transition metal compounds.

Download Full-text

Arrangements of Fe-Centered Zn12 Icosahedra in Fe-Zn Intermetallic Compounds Determined by Ultra-High Resolution Scanning Transmission Electron Microscopy

MRS Proceedings ◽

10.1557/opl.2015.10 ◽

2015 ◽

Vol 1760 ◽

Cited By ~ 4

Author(s):

Norihiko L. Okamoto ◽

Akira Yasuhara ◽

Katsushi Tanaka ◽

Haruyuki Inui

Keyword(s):

Crystal Structure ◽

Electron Microscopy ◽

Transmission Electron Microscopy ◽

High Resolution ◽

Single Crystal ◽

Scanning Transmission Electron Microscopy ◽

Scanning Transmission Electron ◽

Transmission Electron ◽

Deformation Properties ◽

Scanning Transmission

ABSTRACTThe crystal structure of the δ1p phase in the Fe-Zn system has been refined by single-crystal synchrotron X-ray diffraction combined with ultra-high resolution scanning transmission electron microscopy. The crystal structure can be described to build up with Fe-centered Zn12 icosahedra. The deformation properties obtained by single-crystal micropillar compression tests of the δ1p phase is discussed in terms of the arrangement of the Fe-centered Zn12 icosahedra in contrast with the ζ phase in the Fe-Zn system.

Download Full-text

Carborane-Based Carbonic Anhydrase Inhibitors: Insight into CAII/CAIX Specificity from a High-Resolution Crystal Structure, Modeling, and Quantum Chemical Calculations

BioMed Research International ◽

10.1155/2014/389869 ◽

2014 ◽

Vol 2014 ◽

pp. 1-9 ◽

Cited By ~ 11

Author(s):

Pavel Mader ◽

Adam Pecina ◽

Petr Cígler ◽

Martin Lepšík ◽

Václav Šícha ◽

...

Keyword(s):

Crystal Structure ◽

High Resolution ◽

Carbonic Anhydrase ◽

Quantum Chemical Calculations ◽

Quantum Chemical ◽

Computational Analysis ◽

Structure Modeling ◽

Carbonic Anhydrases ◽

Carbonic Anhydrase Inhibitors ◽

Insight Into

Carborane-based compounds are promising lead structures for development of inhibitors of carbonic anhydrases (CAs). Here, we report structural and computational analysis applicable to structure-based design of carborane compounds with selectivity toward the cancer-specific CAIX isoenzyme. We determined the crystal structure of CAII in complex with 1-methylenesulfamide-1,2-dicarba-closo-dodecaborane at 1.0 Å resolution and used this structure to model the 1-methylenesulfamide-1,2-dicarba-closo-dodecaborane interactions with CAIX. A virtual glycine scan revealed the contributions of individual residues to the energy of binding of 1-methylenesulfamide-1,2-dicarba-closo-dodecaborane to CAII and CAIX, respectively.

Download Full-text

Structure of fluorite-like compound based on Nd5Mo3O16with lead partly substituting for neodymium

Acta Crystallographica Section B Structural Science Crystal Engineering and Materials ◽

10.1107/s2052520615003315 ◽

2015 ◽

Vol 71 (2) ◽

pp. 186-193 ◽

Cited By ~ 7

Author(s):

Alexander M. Antipin ◽

Natalia I. Sorokina ◽

Olga A. Alekseeva ◽

Alexandra N. Kuskova ◽

Elena P. Kharitonova ◽

...

Keyword(s):

Crystal Structure ◽

High Resolution ◽

Single Crystal ◽

Experimental Verification ◽

X Ray Diffraction ◽

Transmission Microscopy ◽

X Ray ◽

Oxygen Ion ◽

First Time ◽

Edx Microanalysis

A single crystal of Nd5Mo3O16with lead partly substituting for neodymium, which has a fluorite-like structure, was studied by precision X-ray diffraction, high-resolution transmission microscopy and EDX microanalysis. The crystal structure is determined in the space group Pn\bar 3n. It was found that the Pb atoms substitute in part for Nd atoms in the structure and are located in the vicinity of Nd2 positions. Partial substitutions of Mo cations for Nd positions and of Nd for Mo positions in crystals of theLn5Mo3O16oxide family are corroborated by X-ray diffraction for the first time. The first experimental verification of the location of an additional oxygen ion in the voids abutting MoO4tetrahedra was obtained.

Download Full-text

Combined Rietveld and stereochemical restraint refinement of a protein crystal structure

Journal of Applied Crystallography ◽

10.1107/s002188989901064x ◽

1999 ◽

Vol 32 (6) ◽

pp. 1084-1089 ◽

Cited By ~ 44

Author(s):

R. B. Von Dreele

Keyword(s):

Crystal Structure ◽

High Resolution ◽

Single Crystal ◽

Powder Diffraction ◽

Diffraction Data ◽

Tertiary Structure ◽

Protein Crystal ◽

Powder Diffraction Data ◽

X Ray ◽

Protein Crystal Structure

By combining high-resolution X-ray powder diffraction data and stereochemical restraints, Rietveld refinement of protein crystal structures has been shown to be feasible. A refinement of the 1261-atom protein metmyoglobin was achieved by combining 5338 stereochemical restraints with a 4648-step (dmin= 3.3 Å) powder diffraction pattern to give the residualsRwp= 2.32%,Rp= 1.66%,R(F2) = 3.10%. The resulting tertiary structure of the protein is essentially identical to that obtained from previous single-crystal studies.

Download Full-text

Tuning of crystallization method and ligand conformation to give a mononuclear compound or two-dimensional SCO coordination polymer based on a new semi-rigid V-shaped bis-pyridyl bis-amide ligand

Acta Crystallographica Section C Structural Chemistry ◽

10.1107/s2053229620004854 ◽

2020 ◽

Vol 76 (5) ◽

pp. 412-418

Author(s):

Xiaoyun Hao ◽

Yong Dou ◽

Tong Cao ◽

Lan Qin ◽

Lu Yang ◽

...

Keyword(s):

Coordination Polymer ◽

Single Crystal ◽

Rational Design ◽

High Spin State ◽

Structure Type ◽

Two Dimensional ◽

Thermally Induced ◽

X Ray ◽

X Ray Crystallography ◽

Ligand Conformation

With the new semi-rigid V-shaped bidentate pyridyl amide compound 5-methyl-N,N′-bis(pyridin-4-yl)benzene-1,3-dicarboxamide (L) as an auxiliary ligand and the FeII ion as the metal centre, one mononuclear complex, bis(methanol-κO)bis[5-methyl-N,N′-bis(pyridin-4-yl)benzene-1,3-dicarboxamide-κN]bis(thiocyanato-κN)iron(II), [Fe(SCN)2(C19H16N4O2)2(CH3OH)2] (1), and one two-dimensional coordination polymer, catena-poly[[[bis(thiocyanato-κN)iron(II)]-bis[μ-5-methyl-N,N′-bis(pyridin-4-yl)benzene-1,3-dicarboxamide-κ2 N:N′]] methanol disolvate dihydrate], {[Fe(SCN)2(C19H16N4O2)2]·2CH3OH·2H2O} n (2), were prepared by slow evaporation and H-tube diffusion methods, respectively, indicating the effect of the method of crystallization on the structure type of the target product. Both complexes have been structurally characterized by elemental analysis, IR spectroscopy and single-crystal X-ray crystallography. The single-crystal X-ray diffraction analysis shows that L functions as a monodentate ligand in mononuclear 1, while it coordinates in a bidentate manner to two independent Fe(SCN)2 units in complex 2, with a different conformation from that in 1 and the ligands point in two almost orthogonal directions, therefore leading to a two-dimensional grid-like network. Investigation of the magnetic properties reveals the always high-spin state of the FeII centre over the whole temperature range in 1 and a gradual thermally-induced incomplete spin crossover (SCO) behaviour below 150 K in 2, demonstrating the influence of the different coordination fields on the spin properties of the metal ions. The current results provide useful information for the rational design of functional complexes with different structure dimensionalities by employing different conformations of the ligand and different crystallization methods.

Download Full-text