Biomaterial Database

Histidyl conformations and short N-H...N hydrogen bonds: structure of D,L-histidyl-L,D-histidine pentahydrate. 1991

J A Krause, and P W Baures, and D S Eggleston

Department of Physical and Structural Chemistry, SmithKline Beecham Pharmaceuticals, King of Prussia, PA 19406.

D,L-Histidyl-L,D-histidine pentahydrate, C12H16-N6O3.5H2O, Mr = 382.38, F(000) = 408, crystallizes in the monoclinic space group Pc with the cell dimensions a = 9.971 (2), b = 4.745 (2), c = 19.572 (3) A and beta = 96.08 (1) degree, V = 920.6 A3, Z = 2, D chi = 1.379 g cm-3. mu = 1.083 cm-1, T = 295 K, Mo K alpha, lambda = 0.71073 A. Final R (on F) = 0.040 for 1658 observed reflections with I greater than or equal to 3 sigma (I). This dipeptide crystallizes in a zwitterionic form with protonation of the C-terminal imidazole ring. Both histidine units exist in the g+ or 'closed' conformation with C alpha-C beta torsion angles of 67.2 (3) and 63.6 (3) degrees. Principal torsion angles, omega = 176.8 (2). psi 1 = 161.8 (3) and phi 2 = -152.1 (3) degrees, are indicative of a highly extended trans conformation. Intramolecular hydrogen bonding occurs between the imidazole rings [N2D-H2D1...N1D = 2.724 (4) A]. Intermolecular hydrogen bonding occurs between symmetry-related histidine molecules forming chains along the gamma axis and includes another short [2.764 (4) A] N-H...N interaction. The five water molecules occupy channels between adjacent histidine layers.

UI	MeSH Term	Description	Entries
D008968	Molecular Conformation	The characteristic three-dimensional shape of a molecule.	Molecular Configuration,3D Molecular Structure,Configuration, Molecular,Molecular Structure, Three Dimensional,Three Dimensional Molecular Structure,3D Molecular Structures,Configurations, Molecular,Conformation, Molecular,Conformations, Molecular,Molecular Configurations,Molecular Conformations,Molecular Structure, 3D,Molecular Structures, 3D,Structure, 3D Molecular,Structures, 3D Molecular
D003460	Crystallization	The formation of crystalline substances from solutions or melts. (McGraw-Hill Dictionary of Scientific and Technical Terms, 4th ed)	Crystalline Polymorphs,Polymorphism, Crystallization,Crystal Growth,Polymorphic Crystals,Crystal, Polymorphic,Crystalline Polymorph,Crystallization Polymorphism,Crystallization Polymorphisms,Crystals, Polymorphic,Growth, Crystal,Polymorph, Crystalline,Polymorphic Crystal,Polymorphisms, Crystallization,Polymorphs, Crystalline
D004151	Dipeptides	Peptides composed of two amino acid units.	Dipeptide
D005583	Fourier Analysis	Analysis based on the mathematical function first formulated by Jean-Baptiste-Joseph Fourier in 1807. The function, known as the Fourier transform, describes the sinusoidal pattern of any fluctuating pattern in the physical world in terms of its amplitude and its phase. It has broad applications in biomedicine, e.g., analysis of the x-ray crystallography data pivotal in identifying the double helical nature of DNA and in analysis of other molecules, including viruses, and the modified back-projection algorithm universally used in computerized tomography imaging, etc. (From Segen, The Dictionary of Modern Medicine, 1992)	Fourier Series,Fourier Transform,Analysis, Cyclic,Analysis, Fourier,Cyclic Analysis,Analyses, Cyclic,Cyclic Analyses,Series, Fourier,Transform, Fourier
D006639	Histidine	An essential amino acid that is required for the production of HISTAMINE.	Histidine, L-isomer,L-Histidine,Histidine, L isomer,L-isomer Histidine
D006860	Hydrogen Bonding	A low-energy attractive force between hydrogen and another element. It plays a major role in determining the properties of water, proteins, and other compounds.	Hydrogen Bonds,Bond, Hydrogen,Hydrogen Bond
D014961	X-Ray Diffraction	The scattering of x-rays by matter, especially crystals, with accompanying variation in intensity due to interference effects. Analysis of the crystal structure of materials is performed by passing x-rays through them and registering the diffraction image of the rays (CRYSTALLOGRAPHY, X-RAY). (From McGraw-Hill Dictionary of Scientific and Technical Terms, 4th ed)	Xray Diffraction,Diffraction, X-Ray,Diffraction, Xray,Diffractions, X-Ray,Diffractions, Xray,X Ray Diffraction,X-Ray Diffractions,Xray Diffractions
D015394	Molecular Structure	The location of the atoms, groups or ions relative to one another in a molecule, as well as the number, type and location of covalent bonds.	Structure, Molecular,Molecular Structures,Structures, Molecular