Structural Characterization of a Pentapeptide Derived from a Novel Carbohydrate α-Amino Acid

2007 ◽  
Vol 60 (2) ◽  
pp. 93 ◽  
Author(s):  
Adrian Scaffidi ◽  
Brian W. Skelton ◽  
Robert V. Stick ◽  
Allan H. White
Keyword(s):  
Amino Acid ◽  
Synchrotron Radiation ◽  
Hydrogen Bonds ◽  
Structural Characterization ◽  
Internal Hydrogen ◽  
Radiation Study ◽  
Independent Molecules

Subsequent to our previous report describing several novel carbohydrate α-amino acid dipeptides (and the structural characterization of one of those), and their extension to higher peptides, a synchrotron radiation study of one of those—a pentapeptide—showing its structure to be a well-defined helical array in each of two independent molecules, stabilized by internal hydrogen bonds, is reported.

scholarly journals Synthesis and structural characterization of glycinatodimethylgallium, (C2H4NO2)Ga(CH3)2

1987 ◽  
Vol 65 (6) ◽  
pp. 1349-1352 ◽  
Author(s):  
Steven J. Rettig ◽  
Alan Storr ◽  
James Trotter
Keyword(s):  
Crystal Structure ◽  
Hydrogen Bonds ◽  
Structural Characterization ◽  
Title Compound ◽  
Heavy Atom ◽  
Coordination Geometry ◽  
Tetrahedral Coordination ◽  
Full Matrix ◽  
Independent Molecules

Details of the preparation and crystal structure of the title compound are given. Crystals of glycinatodimethylgallium are monoclinic, a = 12.502(1), b = 12.023(1), c = 10.732(1) Å, β = 110.05(1)°, Z = 8, space group P21/c. The structure was solved by conventional heavy atom methods and was refined by full-matrix least-squares procedures to R = 0.033 and Rw = 0.039 for 1172 reflections with I ≥ 3σ(I). The structure consists of monomeric (C2H4NO2)GaMe2 molecules which are linked together by an extensive network of [Formula: see text] hydrogen bonds. The Ga atoms have tetrahedral coordination geometry with bond lengths averaged over the two crystallographically independent molecules: Ga—O = 1.958(18), Ga—N = 2.031(5), and Ga—C = 1.937(7) Å.

4-(Piperidin-1-yl)pyridinium hexafluorophosphate at 150 K

2003 ◽  
Vol 59 (11) ◽  
pp. o622-o624 ◽  
Author(s):  
Bruce D. James ◽  
Siti Mutrofin ◽  
Brian W. Skelton ◽  
Allan H. White
Keyword(s):  
Hydrogen Bonds ◽  
Structural Characterization ◽  
Title Compound ◽  
Ion Pairs ◽  
Piperidine Ring ◽  
Torsion Angles ◽  
Compound C ◽  
Counter Ions

Structural characterization of the title compound, C10H15N2 +·PF6 −, shows it to be ionic, with the pyridine rather than the piperidine N atom being protonated and forming hydrogen bonds to the counter-ions, resulting in two independent ion pairs. A number of unusual features are noted, in particular the remarkably close inter-ring hydrogen contacts [1.97 (3)–2.00 (3) Å] and the considerable differences in the pair of cations, in respect of the torsion angles within the piperidine ring involving the bonds to either side of the N atom.

scholarly journals Crystallographic and structural characterization of heterometallic platinum compounds. Part II. Heterobinuclear Pt compounds with Pt⋯M (M = transition or lantanide metal) > 3.0 Å

2012 ◽  
Vol 10 (6) ◽  
pp. 1709-1759 ◽  
Author(s):  
Milan Melnik ◽  
Ondrej Sprusansky ◽  
Clive Holloway
Keyword(s):  
Transition Metal ◽  
Chlorine Atom ◽  
Structural Characterization ◽  
Platinum Compounds ◽  
Factors Affecting ◽  
Bond Lengths ◽  
Trigonal Bipyramidal ◽  
Square Planar ◽  
Independent Molecules

AbstractThis review covers almost two hundred and twenty heterobinuclear platinum compounds in which Pt⋯M separation is over 3.0 Å. The M is a transition metal (Cu, Ag, Au, Ti, V, Cr, Mo, W, Mn, Re, Fe, Ru, Os, Co, Rh, Ir, Ni and Pd). There is an example of a lanthanide, Yb and a actinide, U. The Pt atom has oxidation numbers 0, +2 and +4. The Pt coordination geometries include trigonal planar Pt(0); square planar Pt(II); trigonal bipyramidal, and pseudo octahedral Pt(IV), with the most frequent being square planar. The most common ligands for Pt are P and C donor atoms, as well as a chlorine atom. The Pt — Ag distance of 3.002(1) Å is the shortest found in this series. There are examples which contain two crystallographically independent molecules, which differ mostly by degree of distortion and even one unique example, which contains eight such molecules. These are examples of distortion isomerism. Factors affecting bond lengths and angles are discussed and some ambiguities in coordination polyhedral are outlined.

Structural characterization of folded and extended conformations in peptides containing γ amino acids with proteinogenic side chains: crystal structures of γn, (αγ)n and γγδγ sequences

2015 ◽  
Vol 39 (5) ◽  
pp. 3319-3326 ◽  
Author(s):  
Madhusudana M. B. Reddy ◽  
K. Basuroy ◽  
S. Chandrappa ◽  
B. Dinesh ◽  
B. Vasantha ◽  
...  
Keyword(s):  
Amino Acids ◽  
Amino Acid ◽  
Crystal Structures ◽  
Structural Characterization ◽  
Side Chains ◽  
Amino Acid Residues

γn amino acid residues can be incorporated into structures in γn and hybrid sequences containing folded and extended α and δ residues.

Synthesis, crystallization, X-ray structural characterization and solid-state assembly of a cyclic hexapeptoid with propargyl and methoxyethyl side chains

2017 ◽  
Vol 73 (3) ◽  
pp. 399-412 ◽  
Author(s):  
Consiglia Tedesco ◽  
Eleonora Macedi ◽  
Alessandra Meli ◽  
Giovanni Pierri ◽  
Giorgio Della Sala ◽  
...  
Keyword(s):  
Solid State ◽  
Hydrogen Bonds ◽  
Structural Characterization ◽  
Crystal Form ◽  
Side Chains ◽  
Crystal Forms ◽  
Hydrate Crystal ◽  
The Stability ◽  
Efficient Packing

The synthesis and the structural characterization of a cyclic hexapeptoid with four methoxyethyl and two propargyl side chains have disclosed the presence of a hydrate crystal form [form (I)] and an anhydrous crystal form [form (II)]. The relative amounts of form (I) and form (II) in the as-purified product were determined by Rietveld refinement and depend on the purification procedures. In crystal form (I), peptoid molecules assemble in a columnar arrangement by means of side-chain-to-backbone C=CH...OC hydrogen bonds. In the anhydrous crystal form (II), cyclopeptoid molecules form ribbons by means of backbone-to-backbone CH2...OC hydrogen bonds, thus mimicking β-sheet secondary structures in proteins. In both crystal forms side chains act as joints among the columns or the ribbons and contribute to the stability of the whole solid-state assembly. Water molecules in the hydrate crystal form (I) bridge columns of cyclic peptoid molecules, providing a more efficient packing.

scholarly journals Biological and Structural Characterization of a Host-Adapting Amino Acid in Influenza Virus

2010 ◽  
Vol 6 (8) ◽  
pp. e1001034 ◽  
Author(s):  
Shinya Yamada ◽  
Masato Hatta ◽  
Bart L. Staker ◽  
Shinji Watanabe ◽  
Masaki Imai ◽  
...  
Keyword(s):  
Influenza Virus ◽  
Amino Acid ◽  
Structural Characterization

scholarly journals Crystallographic and structural characterization of heterometallic platinum complexes Part V. Heteropentanuclear complexes

2014 ◽  
Vol 12 (3) ◽  
pp. 283-306 ◽  
Author(s):  
Milan Melník ◽  
Peter Mikuš ◽  
Clive Holloway
Keyword(s):  
Structural Characterization ◽  
Structural Parameters ◽  
Bond Distance ◽  
Platinum Complexes ◽  
Trigonal Bipyramidal ◽  
Metal Atoms ◽  
Independent Molecules

AbstractThis review classifies and analyzes over eighty heteropentanuclear Pt complexes. There are eight types of metal combinations: Pt4M, Pt3M2, Pt2M3, PtM4, Pt3MM′, Pt2M2M′, PtM2M′2 and PtM3M′. The five metal atoms are in a wide variety of arrangements: trigonal-bipyramidal (most common), square-pyramidal, spike-triangular, butterfly, cubane, linear and one unique. Platinum bonds to a variety of triad partner metal atoms, soft, through borderline to hard. The shortest Pt-M bond distances for non-transition and transition M are 2.406(4) Å (M = Ge) and 2.30(1) Å (M = Co). The shortest Pt-Pt bond distance is 2.580(1) Å. Several relationships between the structural parameters were found and are discussed. Several complexes exist in two isomeric forms and others contain two crystallographically independent molecules. Both the isomers as well as independent molecules are examples of distortion isomerism.

Structural Characterization of Multi-Quantum Wells in Electroabsorption-Modulated Lasers by using Synchrotron Radiation Micrometer-Beams

2010 ◽  
Vol 22 (18) ◽  
pp. 2050-2054 ◽  
Author(s):  
Lorenzo Mino ◽  
Diego Gianolio ◽  
Giovanni Agostini ◽  
Andrea Piovano ◽  
Marco Truccato ◽  
...  
Keyword(s):  
Synchrotron Radiation ◽  
Quantum Wells ◽  
Structural Characterization
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